diff --git a/CHANGES.md b/CHANGES.md
index 508fee230a..8e6f79339f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,6 +10,8 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Added
+* Added support for JSON formatting based on [Gson](https://github.com/google/gson) ([#1125](https://github.com/diffplug/spotless/pull/1125)).
 
 ### Changed
 
diff --git a/README.md b/README.md
index 6ace09631d..f95ea7a7ca 100644
--- a/README.md
+++ b/README.md
@@ -30,8 +30,8 @@ It's easy to build such a function, but there are some gotchas and lots of integ
 ## Current feature matrix
 
 <!---freshmark matrix
-function lib(className)   { return '| [`' + className + '`](lib/src/main/java/com/diffplug/spotless/' + className.replace('.', '/') + '.java) | ' }
-function extra(className) { return '| [`' + className + '`](lib-extra/src/main/java/com/diffplug/spotless/extra/' + className.replace('.', '/') + '.java) | ' }
+function lib(className)   { return '| [`' + className + '`](lib/src/main/java/com/diffplug/spotless/' + className.replaceAll('\\.', '/') + '.java) | ' }
+function extra(className) { return '| [`' + className + '`](lib-extra/src/main/java/com/diffplug/spotless/extra/' + className.replaceAll('\\.', '/') + '.java) | ' }
 
 //                                               | GRADLE        | MAVEN        | SBT          | (new)   |
 output = [
@@ -61,6 +61,8 @@ lib('java.ImportOrderStep')                      +'{{yes}}       | {{yes}}
 lib('java.PalantirJavaFormatStep')               +'{{yes}}       | {{yes}}      | {{no}}       | {{no}}  |',
 lib('java.RemoveUnusedImportsStep')              +'{{yes}}       | {{yes}}      | {{yes}}      | {{no}}  |',
 extra('java.EclipseJdtFormatterStep')            +'{{yes}}       | {{yes}}      | {{yes}}      | {{no}}  |',
+lib('json.gson.GsonStep')                        +'{{yes}}       | {{no}}       | {{no}}       | {{no}}  |',
+lib('json.JsonSimpleStep')                       +'{{yes}}       | {{no}}       | {{no}}       | {{no}}  |',
 lib('kotlin.KtLintStep')                         +'{{yes}}       | {{yes}}      | {{yes}}      | {{no}}  |',
 lib('kotlin.KtfmtStep')                          +'{{yes}}       | {{yes}}      | {{no}}       | {{no}}  |',
 lib('kotlin.DiktatStep')                         +'{{yes}}       | {{yes}}      | {{no}}       | {{no}}  |',
@@ -102,6 +104,8 @@ extra('wtp.EclipseWtpFormatterStep')             +'{{yes}}       | {{yes}}
 | [`java.PalantirJavaFormatStep`](lib/src/main/java/com/diffplug/spotless/java/PalantirJavaFormatStep.java) | :+1:       | :+1:      | :white_large_square:       | :white_large_square:  |
 | [`java.RemoveUnusedImportsStep`](lib/src/main/java/com/diffplug/spotless/java/RemoveUnusedImportsStep.java) | :+1:       | :+1:      | :+1:      | :white_large_square:  |
 | [`java.EclipseJdtFormatterStep`](lib-extra/src/main/java/com/diffplug/spotless/extra/java/EclipseJdtFormatterStep.java) | :+1:       | :+1:      | :+1:      | :white_large_square:  |
+| [`json.gson.GsonStep`](lib/src/main/java/com/diffplug/spotless/json/gson/GsonStep.java) | :+1:       | :white_large_square:       | :white_large_square:       | :white_large_square:  |
+| [`json.JsonSimpleStep`](lib/src/main/java/com/diffplug/spotless/json/JsonSimpleStep.java) | :+1:       | :white_large_square:       | :white_large_square:       | :white_large_square:  |
 | [`kotlin.KtLintStep`](lib/src/main/java/com/diffplug/spotless/kotlin/KtLintStep.java) | :+1:       | :+1:      | :+1:      | :white_large_square:  |
 | [`kotlin.KtfmtStep`](lib/src/main/java/com/diffplug/spotless/kotlin/KtfmtStep.java) | :+1:       | :+1:      | :white_large_square:       | :white_large_square:  |
 | [`kotlin.DiktatStep`](lib/src/main/java/com/diffplug/spotless/kotlin/DiktatStep.java) | :+1:       | :+1:      | :white_large_square:       | :white_large_square:  |
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/GsonBuilderWrapper.java b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonBuilderWrapper.java
new file mode 100644
index 0000000000..c2e56f39b8
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonBuilderWrapper.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+import com.diffplug.spotless.JarState;
+
+class GsonBuilderWrapper extends GsonWrapperBase {
+
+	private final Constructor<?> constructor;
+	private final Method serializeNullsMethod;
+	private final Method disableHtmlEscapingMethod;
+	private final Method createMethod;
+
+	GsonBuilderWrapper(JarState jarState) {
+		Class<?> clazz = loadClass(jarState.getClassLoader(), "com.google.gson.GsonBuilder");
+		this.constructor = getConstructor(clazz);
+		this.serializeNullsMethod = getMethod(clazz, "serializeNulls");
+		this.disableHtmlEscapingMethod = getMethod(clazz, "disableHtmlEscaping");
+		this.createMethod = getMethod(clazz, "create");
+	}
+
+	Object createGsonBuilder() {
+		return newInstance(constructor);
+	}
+
+	Object serializeNulls(Object gsonBuilder) {
+		return invoke(serializeNullsMethod, gsonBuilder);
+	}
+
+	Object disableHtmlEscaping(Object gsonBuilder) {
+		return invoke(disableHtmlEscapingMethod, gsonBuilder);
+	}
+
+	Object create(Object gsonBuilder) {
+		return invoke(createMethod, gsonBuilder);
+	}
+
+}
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/GsonStep.java b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonStep.java
new file mode 100644
index 0000000000..06519ae39d
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonStep.java
@@ -0,0 +1,106 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.io.StringWriter;
+import java.util.Collections;
+import java.util.Objects;
+
+import com.diffplug.spotless.FormatterFunc;
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.JarState;
+import com.diffplug.spotless.Provisioner;
+
+public class GsonStep {
+	private static final String MAVEN_COORDINATES = "com.google.code.gson:gson";
+
+	public static FormatterStep create(int indentSpaces, boolean sortByKeys, boolean escapeHtml, String version, Provisioner provisioner) {
+		Objects.requireNonNull(provisioner, "provisioner cannot be null");
+		return FormatterStep.createLazy("gson", () -> new State(indentSpaces, sortByKeys, escapeHtml, version, provisioner), State::toFormatter);
+	}
+
+	private static final class State implements Serializable {
+		private static final long serialVersionUID = -1493479043249379485L;
+
+		private final int indentSpaces;
+		private final boolean sortByKeys;
+		private final boolean escapeHtml;
+		private final JarState jarState;
+
+		private State(int indentSpaces, boolean sortByKeys, boolean escapeHtml, String version, Provisioner provisioner) throws IOException {
+			this.indentSpaces = indentSpaces;
+			this.sortByKeys = sortByKeys;
+			this.escapeHtml = escapeHtml;
+			this.jarState = JarState.from(MAVEN_COORDINATES + ":" + version, provisioner);
+		}
+
+		FormatterFunc toFormatter() {
+			JsonWriterWrapper jsonWriterWrapper = new JsonWriterWrapper(jarState);
+			JsonElementWrapper jsonElementWrapper = new JsonElementWrapper(jarState);
+			JsonObjectWrapper jsonObjectWrapper = new JsonObjectWrapper(jarState, jsonElementWrapper);
+			GsonBuilderWrapper gsonBuilderWrapper = new GsonBuilderWrapper(jarState);
+			GsonWrapper gsonWrapper = new GsonWrapper(jarState, jsonElementWrapper, jsonWriterWrapper);
+
+			Object gsonBuilder = gsonBuilderWrapper.serializeNulls(gsonBuilderWrapper.createGsonBuilder());
+			if (!escapeHtml) {
+				gsonBuilder = gsonBuilderWrapper.disableHtmlEscaping(gsonBuilder);
+			}
+			Object gson = gsonBuilderWrapper.create(gsonBuilder);
+
+			return inputString -> {
+				String result;
+				if (inputString.isEmpty()) {
+					result = "";
+				} else {
+					Object jsonElement = gsonWrapper.fromJson(gson, inputString, jsonElementWrapper.getWrappedClass());
+					if (jsonElement == null) {
+						throw new AssertionError(GsonWrapperBase.FAILED_TO_PARSE_ERROR_MESSAGE);
+					}
+					if (sortByKeys && jsonElementWrapper.isJsonObject(jsonElement)) {
+						jsonElement = sortByKeys(jsonObjectWrapper, jsonElementWrapper, jsonElement);
+					}
+					try (StringWriter stringWriter = new StringWriter()) {
+						Object jsonWriter = jsonWriterWrapper.createJsonWriter(stringWriter);
+						jsonWriterWrapper.setIndent(jsonWriter, generateIndent(indentSpaces));
+						gsonWrapper.toJson(gson, jsonElement, jsonWriter);
+						result = stringWriter + "\n";
+					}
+				}
+				return result;
+			};
+		}
+
+		private Object sortByKeys(JsonObjectWrapper jsonObjectWrapper, JsonElementWrapper jsonElementWrapper, Object jsonObject) {
+			Object result = jsonObjectWrapper.createJsonObject();
+			jsonObjectWrapper.keySet(jsonObject).stream().sorted()
+					.forEach(key -> {
+						Object element = jsonObjectWrapper.get(jsonObject, key);
+						if (jsonElementWrapper.isJsonObject(element)) {
+							element = sortByKeys(jsonObjectWrapper, jsonElementWrapper, element);
+						}
+						jsonObjectWrapper.add(result, key, element);
+					});
+			return result;
+		}
+
+		private String generateIndent(int indentSpaces) {
+			return String.join("", Collections.nCopies(indentSpaces, " "));
+		}
+	}
+
+}
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/GsonWrapper.java b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonWrapper.java
new file mode 100644
index 0000000000..eaca499eed
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonWrapper.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.lang.reflect.Method;
+
+import com.diffplug.spotless.JarState;
+
+class GsonWrapper extends GsonWrapperBase {
+
+	private final Method fromJsonMethod;
+	private final Method toJsonMethod;
+
+	GsonWrapper(JarState jarState, JsonElementWrapper jsonElementWrapper, JsonWriterWrapper jsonWriterWrapper) {
+		Class<?> clazz = loadClass(jarState.getClassLoader(), "com.google.gson.Gson");
+		this.fromJsonMethod = getMethod(clazz, "fromJson", String.class, Class.class);
+		this.toJsonMethod = getMethod(clazz, "toJson", jsonElementWrapper.getWrappedClass(), jsonWriterWrapper.getWrappedClass());
+	}
+
+	Object fromJson(Object gson, String json, Class<?> type) {
+		return invoke(fromJsonMethod, gson, json, type);
+	}
+
+	void toJson(Object gson, Object jsonElement, Object jsonWriter) {
+		invoke(toJsonMethod, gson, jsonElement, jsonWriter);
+	}
+
+}
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/GsonWrapperBase.java b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonWrapperBase.java
new file mode 100644
index 0000000000..24d12a5722
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/GsonWrapperBase.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+abstract class GsonWrapperBase {
+
+	static final String INCOMPATIBLE_ERROR_MESSAGE = "There was a problem interacting with Gson; maybe you set an incompatible version?";
+	static final String FAILED_TO_PARSE_ERROR_MESSAGE = "Unable to format JSON";
+
+	protected final Class<?> loadClass(ClassLoader classLoader, String className) {
+		try {
+			return classLoader.loadClass(className);
+		} catch (ClassNotFoundException cause) {
+			throw new IllegalStateException(INCOMPATIBLE_ERROR_MESSAGE, cause);
+		}
+	}
+
+	protected final Constructor<?> getConstructor(Class<?> clazz, Class<?>... argumentTypes) {
+		try {
+			return clazz.getConstructor(argumentTypes);
+		} catch (NoSuchMethodException cause) {
+			throw new IllegalStateException(INCOMPATIBLE_ERROR_MESSAGE, cause);
+		}
+	}
+
+	protected final Method getMethod(Class<?> clazz, String name, Class<?>... argumentTypes) {
+		try {
+			return clazz.getMethod(name, argumentTypes);
+		} catch (NoSuchMethodException cause) {
+			throw new IllegalStateException(INCOMPATIBLE_ERROR_MESSAGE, cause);
+		}
+	}
+
+	protected final <T> T newInstance(Constructor<T> constructor, Object... args) {
+		try {
+			return constructor.newInstance(args);
+		} catch (InstantiationException | IllegalAccessException cause) {
+			throw new IllegalStateException(INCOMPATIBLE_ERROR_MESSAGE, cause);
+		} catch (InvocationTargetException cause) {
+			throw new AssertionError(FAILED_TO_PARSE_ERROR_MESSAGE, cause.getCause());
+		}
+	}
+
+	protected Object invoke(Method method, Object targetObject, Object... args) {
+		try {
+			return method.invoke(targetObject, args);
+		} catch (IllegalAccessException cause) {
+			throw new IllegalStateException(INCOMPATIBLE_ERROR_MESSAGE, cause);
+		} catch (InvocationTargetException cause) {
+			throw new AssertionError(FAILED_TO_PARSE_ERROR_MESSAGE, cause.getCause());
+		}
+	}
+
+}
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/JsonElementWrapper.java b/lib/src/main/java/com/diffplug/spotless/json/gson/JsonElementWrapper.java
new file mode 100644
index 0000000000..ffdfa649ce
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/JsonElementWrapper.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.lang.reflect.Method;
+
+import com.diffplug.spotless.JarState;
+
+class JsonElementWrapper extends GsonWrapperBase {
+
+	private final Class<?> clazz;
+	private final Method isJsonObjectMethod;
+
+	JsonElementWrapper(JarState jarState) {
+		this.clazz = loadClass(jarState.getClassLoader(), "com.google.gson.JsonElement");
+		this.isJsonObjectMethod = getMethod(clazz, "isJsonObject");
+	}
+
+	boolean isJsonObject(Object jsonElement) {
+		return (boolean) invoke(isJsonObjectMethod, jsonElement);
+	}
+
+	Class<?> getWrappedClass() {
+		return clazz;
+	}
+
+}
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/JsonObjectWrapper.java b/lib/src/main/java/com/diffplug/spotless/json/gson/JsonObjectWrapper.java
new file mode 100644
index 0000000000..35ec0d876b
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/JsonObjectWrapper.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.util.Set;
+
+import com.diffplug.spotless.JarState;
+
+class JsonObjectWrapper extends GsonWrapperBase {
+
+	private final Constructor<?> constructor;
+	private final Method keySetMethod;
+	private final Method getMethod;
+	private final Method addMethod;
+
+	JsonObjectWrapper(JarState jarState, JsonElementWrapper jsonElementWrapper) {
+		Class<?> clazz = loadClass(jarState.getClassLoader(), "com.google.gson.JsonObject");
+		this.constructor = getConstructor(clazz);
+		this.keySetMethod = getMethod(clazz, "keySet");
+		this.getMethod = getMethod(clazz, "get", String.class);
+		this.addMethod = getMethod(clazz, "add", String.class, jsonElementWrapper.getWrappedClass());
+	}
+
+	Object createJsonObject() {
+		return newInstance(constructor);
+	}
+
+	@SuppressWarnings("unchecked")
+	Set<String> keySet(Object jsonObject) {
+		return (Set<String>) invoke(keySetMethod, jsonObject);
+	}
+
+	Object get(Object jsonObject, String key) {
+		return invoke(getMethod, jsonObject, key);
+	}
+
+	void add(Object jsonObject, String key, Object element) {
+		invoke(addMethod, jsonObject, key, element);
+	}
+
+}
diff --git a/lib/src/main/java/com/diffplug/spotless/json/gson/JsonWriterWrapper.java b/lib/src/main/java/com/diffplug/spotless/json/gson/JsonWriterWrapper.java
new file mode 100644
index 0000000000..c9d682e2c2
--- /dev/null
+++ b/lib/src/main/java/com/diffplug/spotless/json/gson/JsonWriterWrapper.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import java.io.Writer;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+import com.diffplug.spotless.JarState;
+
+class JsonWriterWrapper extends GsonWrapperBase {
+
+	private final Class<?> clazz;
+	private final Constructor<?> constructor;
+	private final Method setIndentMethod;
+
+	JsonWriterWrapper(JarState jarState) {
+		this.clazz = loadClass(jarState.getClassLoader(), "com.google.gson.stream.JsonWriter");
+		this.constructor = getConstructor(clazz, Writer.class);
+		this.setIndentMethod = getMethod(clazz, "setIndent", String.class);
+	}
+
+	Object createJsonWriter(Writer writer) {
+		return newInstance(constructor, writer);
+	}
+
+	void setIndent(Object jsonWriter, String indent) {
+		invoke(setIndentMethod, jsonWriter, indent);
+	}
+
+	Class<?> getWrappedClass() {
+		return clazz;
+	}
+
+}
diff --git a/plugin-gradle/CHANGES.md b/plugin-gradle/CHANGES.md
index 3c01b42312..58030e0527 100644
--- a/plugin-gradle/CHANGES.md
+++ b/plugin-gradle/CHANGES.md
@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `3.27.0`).
 
 ## [Unreleased]
+### Added
+* Added support for JSON formatting based on [Gson](https://github.com/google/gson) ([#1125](https://github.com/diffplug/spotless/pull/1125)).
 
 ### Changed
 
diff --git a/plugin-gradle/README.md b/plugin-gradle/README.md
index ffc52bd923..7a6089850c 100644
--- a/plugin-gradle/README.md
+++ b/plugin-gradle/README.md
@@ -595,6 +595,7 @@ spotless {
     simple() // has its own section below
     prettier().config(['parser': 'json']) // see Prettier section below
     eclipseWtp('json') // see Eclipse web tools platform section
+    gson() // has its own section below
   }
 }
 ```
@@ -614,6 +615,30 @@ spotless {
 }
 ```
 
+### Gson
+
+Uses Google Gson to also allow sorting by keys besides custom indentation - useful for i18n files.
+
+```gradle
+spotless {
+  json {
+    target 'src/**/*.json'
+    gson()
+      .indentWithSpaces(6) // optional: specify the number of spaces to use
+      .sortByKeys()        // optional: sort JSON by its keys
+      .escapeHtml()        // optional: escape HTML in values
+      .version('2.8.1')    // optional: specify version
+  }
+}
+```
+
+Notes:
+* There's no option in Gson to leave HTML as-is (i.e. escaped HTML would remain escaped, raw would remain raw). Either
+all HTML characters are written escaped or none. Set `escapeHtml` if you prefer the former.
+* `sortByKeys` will apply lexicographic order on the keys of the input JSON. See the
+[javadoc of String](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/String.html#compareTo(java.lang.String))
+for details.
+
 <a name="applying-prettier-to-javascript--flow--typescript--css--scss--less--jsx--graphql--yaml--etc"></a>
 
 ## Prettier
diff --git a/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JsonExtension.java b/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JsonExtension.java
index e15d395f3b..25182fa4bc 100644
--- a/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JsonExtension.java
+++ b/plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JsonExtension.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2021 DiffPlug
+ * Copyright 2016-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,9 +19,11 @@
 
 import com.diffplug.spotless.FormatterStep;
 import com.diffplug.spotless.json.JsonSimpleStep;
+import com.diffplug.spotless.json.gson.GsonStep;
 
 public class JsonExtension extends FormatExtension {
 	private static final int DEFAULT_INDENTATION = 4;
+	private static final String DEFAULT_GSON_VERSION = "2.8.9";
 	static final String NAME = "json";
 
 	@Inject
@@ -41,6 +43,10 @@ public SimpleConfig simple() {
 		return new SimpleConfig(DEFAULT_INDENTATION);
 	}
 
+	public GsonConfig gson() {
+		return new GsonConfig();
+	}
+
 	public class SimpleConfig {
 		private int indent;
 
@@ -59,4 +65,47 @@ private FormatterStep createStep() {
 		}
 	}
 
+	public class GsonConfig {
+		private int indentSpaces;
+		private boolean sortByKeys;
+		private boolean escapeHtml;
+		private String version;
+
+		public GsonConfig() {
+			this.indentSpaces = DEFAULT_INDENTATION;
+			this.sortByKeys = false;
+			this.escapeHtml = false;
+			this.version = DEFAULT_GSON_VERSION;
+			addStep(createStep());
+		}
+
+		public GsonConfig indentWithSpaces(int indentSpaces) {
+			this.indentSpaces = indentSpaces;
+			replaceStep(createStep());
+			return this;
+		}
+
+		public GsonConfig sortByKeys() {
+			this.sortByKeys = true;
+			replaceStep(createStep());
+			return this;
+		}
+
+		public GsonConfig escapeHtml() {
+			this.escapeHtml = true;
+			replaceStep(createStep());
+			return this;
+		}
+
+		public GsonConfig version(String version) {
+			this.version = version;
+			replaceStep(createStep());
+			return this;
+		}
+
+		private FormatterStep createStep() {
+			return GsonStep.create(indentSpaces, sortByKeys, escapeHtml, version, provisioner());
+		}
+	}
+
 }
diff --git a/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/JsonExtensionTest.java b/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/JsonExtensionTest.java
index edcd4b428f..e2fb9f70aa 100644
--- a/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/JsonExtensionTest.java
+++ b/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/JsonExtensionTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,7 +21,7 @@
 
 class JsonExtensionTest extends GradleIntegrationHarness {
 	@Test
-	void defaultFormatting() throws IOException {
+	void simpleDefaultFormatting() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
 				"    id 'java'",
@@ -42,7 +42,7 @@ void defaultFormatting() throws IOException {
 	}
 
 	@Test
-	void formattingWithCustomNumberOfSpaces() throws IOException {
+	void simpleFormattingWithCustomNumberOfSpaces() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
 				"    id 'java'",
@@ -59,4 +59,83 @@ void formattingWithCustomNumberOfSpaces() throws IOException {
 		gradleRunner().withArguments("spotlessApply").build();
 		assertFile("src/main/resources/example.json").sameAsResource("json/singletonArrayAfter6Spaces.json");
 	}
+
+	@Test
+	void gsonDefaultFormatting() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'java'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    json {",
+				"    target 'examples/**/*.json'",
+				"    gson()",
+				"}",
+				"}");
+		setFile("src/main/resources/example.json").toResource("json/nestedObjectBefore.json");
+		setFile("examples/main/resources/example.json").toResource("json/nestedObjectBefore.json");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/resources/example.json").sameAsResource("json/nestedObjectBefore.json");
+		assertFile("examples/main/resources/example.json").sameAsResource("json/nestedObjectAfter.json");
+	}
+
+	@Test
+	void gsonFormattingWithCustomNumberOfSpaces() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'java'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    json {",
+				"    target 'src/**/*.json'",
+				"    gson().indentWithSpaces(6)",
+				"}",
+				"}");
+		setFile("src/main/resources/example.json").toResource("json/singletonArrayBefore.json");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/resources/example.json").sameAsResource("json/singletonArrayAfter6Spaces.json");
+	}
+
+	@Test
+	void gsonFormattingWithSortingByKeys() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'java'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    json {",
+				"    target 'src/**/*.json'",
+				"    gson().sortByKeys()",
+				"}",
+				"}");
+		setFile("src/main/resources/example.json").toResource("json/sortByKeysBefore.json");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/resources/example.json").sameAsResource("json/sortByKeysAfter.json");
+	}
+
+	@Test
+	void gsonFormattingWithHtmlEscape() throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'java'",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"spotless {",
+				"    json {",
+				"    target 'src/**/*.json'",
+				"    gson().escapeHtml()",
+				"}",
+				"}");
+		setFile("src/main/resources/example.json").toResource("json/escapeHtmlGsonBefore.json");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("src/main/resources/example.json").sameAsResource("json/escapeHtmlGsonAfter.json");
+	}
+
 }
diff --git a/testlib/src/main/resources/json/cucumberJsonSampleGsonAfter.json b/testlib/src/main/resources/json/cucumberJsonSampleGsonAfter.json
new file mode 100644
index 0000000000..07e87bfd38
--- /dev/null
+++ b/testlib/src/main/resources/json/cucumberJsonSampleGsonAfter.json
@@ -0,0 +1,660 @@
+[
+    {
+        "id": "account-holder-withdraws-cash",
+        "tags": [
+            {
+                "name": "@featureTag",
+                "line": 1
+            }
+        ],
+        "description": "This is description of the feature",
+        "name": "1st feature",
+        "keyword": "Feature",
+        "line": 2,
+        "elements": [
+            {
+                "description": "Perfect background",
+                "name": "Activate Credit Card",
+                "keyword": "Background",
+                "line": 7,
+                "steps": [
+                    {
+                        "result": {
+                            "duration": 99107447000,
+                            "status": "passed"
+                        },
+                        "name": "I have a new credit card",
+                        "keyword": "Given ",
+                        "line": 8,
+                        "match": {
+                            "location": "ATMScenario.I_have_a_new_credit_card()"
+                        },
+                        "embeddings": [
+                            {
+                                "mime_type": "image/url",
+                                "data": ""
+                            },
+                            {
+                                "data": "",
+                                "media": {
+                                    "type": "text/plain"
+                                }
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 9520000,
+                            "status": "passed"
+                        },
+                        "name": "My credit card is described as follow:",
+                        "keyword": "And ",
+                        "line": 9,
+                        "match": {
+                            "location": "ATMScenario.My_credit_card_is_described_as_follow"
+                        },
+                        "doc_string": {
+                            "content_type": "",
+                            "line": 10,
+                            "value": "{\n\"issuer\": {\n\"name\": \"Real Bank Inc.\",\n\"isn:\": \"RB55800093842N\"\n},\n\"card_number\": \"4896 0215 8478 6325\",\n\"holder\": \"A guy\"\n}"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 7040000,
+                            "status": "passed"
+                        },
+                        "name": "I confirm my pin number",
+                        "keyword": "When ",
+                        "line": 18,
+                        "match": {
+                            "location": "ATMScenario.I_confirm_my_pin_number()"
+                        },
+                        "rows": [
+                            {
+                                "cells": [
+                                    "Müller",
+                                    "Deutschland"
+                                ],
+                                "line": 2
+                            },
+                            {
+                                "cells": [
+                                    "Nováková",
+                                    "Česko"
+                                ],
+                                "line": 3
+                            },
+                            {
+                                "cells": [
+                                    "Kovačević",
+                                    "Hrvatska"
+                                ],
+                                "line": 4
+                            },
+                            {
+                                "cells": [
+                                    "Παπαδόπουλος",
+                                    "Παπαδόπουλος"
+                                ],
+                                "line": 5
+                            },
+                            {
+                                "cells": [
+                                    "罗/羅",
+                                    "中國"
+                                ],
+                                "line": 6
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 111111,
+                            "status": "passed"
+                        },
+                        "name": "the card should be activated",
+                        "keyword": "Then ",
+                        "line": 19,
+                        "match": {
+                            "location": "ATMScenario.the_card_should_be_activated()"
+                        }
+                    }
+                ],
+                "type": "background"
+            },
+            {
+                "id": "account-holder-withdraws-cash;account-has-'sufficient-funds';;2",
+                "tags": [
+                    {
+                        "name": "@fast",
+                        "line": 21
+                    },
+                    {
+                        "name": "@featureTag",
+                        "line": 1
+                    },
+                    {
+                        "name": "@checkout",
+                        "line": 21
+                    }
+                ],
+                "description": "Account holder withdraws cash",
+                "name": "Account has <sufficient funds>",
+                "keyword": "Scenario Outline",
+                "line": 33,
+                "steps": [
+                    {
+                        "result": {
+                            "duration": 17007000,
+                            "status": "passed"
+                        },
+                        "name": "the account balance is 100",
+                        "keyword": "Given ",
+                        "line": 23,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 23
+                                }
+                            ],
+                            "location": "ATMScenario.createAccount(int)"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 33444444,
+                            "status": "passed"
+                        },
+                        "name": "the card is valid",
+                        "keyword": "And ",
+                        "line": 24,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "",
+                                    "offset": 0
+                                }
+                            ],
+                            "location": "ATMScenario.createCreditCard()"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 44333333,
+                            "status": "passed"
+                        },
+                        "name": "100 is contained in the machine",
+                        "keyword": "And ",
+                        "line": 25,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 0
+                                }
+                            ],
+                            "location": "ATMScenario.createATM(int)"
+                        },
+                        "matchedColumns": [
+                            1
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 11000001,
+                            "status": "passed"
+                        },
+                        "name": "the Account Holder requests 10, entering PIN 1234",
+                        "keyword": "When ",
+                        "line": 26,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "10",
+                                    "offset": 28
+                                },
+                                {
+                                    "val": "1234",
+                                    "offset": 45
+                                }
+                            ],
+                            "location": "ATMScenario.requestMoney(int)"
+                        },
+                        "matchedColumns": [
+                            2
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 3220000,
+                            "status": "passed"
+                        },
+                        "name": "the ATM should dispense 10 monetary units",
+                        "keyword": "Then ",
+                        "line": 27,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "10",
+                                    "offset": 24
+                                },
+                                {
+                                    "val": "",
+                                    "offset": 0
+                                }
+                            ],
+                            "location": "ATMScenario.checkMoney(int)"
+                        },
+                        "matchedColumns": [
+                            3
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 30000000,
+                            "status": "passed"
+                        },
+                        "name": "the account balance should be 90",
+                        "keyword": "And ",
+                        "line": 28,
+                        "arguments": [
+                            {
+                                "rows": [
+                                    {
+                                        "cells": [
+                                            "max",
+                                            "min"
+                                        ]
+                                    },
+                                    {
+                                        "cells": [
+                                            "20",
+                                            "3"
+                                        ]
+                                    }
+                                ]
+                            }
+                        ],
+                        "match": {
+                            "location": "ATMScenario.checkBalance(int)"
+                        },
+                        "matchedColumns": [
+                            2
+                        ]
+                    }
+                ],
+                "type": "scenario",
+                "after": [
+                    {
+                        "result": {
+                            "duration": 60744700,
+                            "status": "passed",
+                            "error_message": "Completed"
+                        },
+                        "match": {
+                            "location": "MachineFactory.timeout()"
+                        }
+                    }
+                ]
+            }
+        ],
+        "uri": "net/masterthought/example(s)/ATM:東京.feature"
+    },
+    {
+        "id": "account-holder-withdraws-more-cash",
+        "description": "As an Account Holder\nI want to withdraw cash from an ATM,<br/>so that I can get money when the bank is closed",
+        "name": "Second feature",
+        "keyword": "Feature",
+        "line": 1,
+        "elements": [
+            {
+                "id": "account-holder-withdraws-more-cash;account-has-sufficient-funds;;2",
+                "tags": [
+                    {
+                        "name": "@checkout",
+                        "line": 101
+                    }
+                ],
+                "before": [
+                    {
+                        "output": [
+                            "System version: beta3"
+                        ],
+                        "result": {
+                            "duration": 10744700,
+                            "status": "passed"
+                        },
+                        "match": {
+                            "location": "MachineFactory.findCashMachine()"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 1000001,
+                            "status": "failed",
+                            "error_message": "   \n"
+                        },
+                        "match": {
+                            "location": "MachineFactory.wait()"
+                        }
+                    }
+                ],
+                "description": "Account holder withdraws more cash",
+                "name": "Account may not have sufficient funds",
+                "keyword": "Scenario Outline",
+                "line": 19,
+                "steps": [
+                    {
+                        "result": {
+                            "status": "undefined"
+                        },
+                        "name": "the account balance is 100",
+                        "keyword": "Given ",
+                        "line": 7,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 23
+                                },
+                                {}
+                            ]
+                        },
+                        "matchedColumns": [
+                            0
+                        ],
+                        "before": [
+                            {
+                                "embeddings": [
+                                    {
+                                        "mime_type": "text/plain",
+                                        "data": ""
+                                    }
+                                ],
+                                "result": {
+                                    "duration": 410802047,
+                                    "status": "failed"
+                                }
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 13000,
+                            "status": "passed"
+                        },
+                        "name": "the card is valid",
+                        "keyword": "And ",
+                        "line": 8,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "",
+                                    "offset": 17
+                                }
+                            ],
+                            "location": "ATMScenario.createCreditCard()"
+                        },
+                        "after": [
+                            {
+                                "result": {
+                                    "duration": 410802048,
+                                    "status": "passed"
+                                },
+                                "match": {
+                                    "location": "StepHook.afterStep()"
+                                }
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 36000,
+                            "status": "passed"
+                        },
+                        "name": "the machine contains 100",
+                        "keyword": "And ",
+                        "line": 9,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 21
+                                }
+                            ],
+                            "location": "ATMScenario.createATM(int)"
+                        },
+                        "matchedColumns": [
+                            1
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 32000,
+                            "status": "passed"
+                        },
+                        "name": "the Account Holder requests 20",
+                        "keyword": "When ",
+                        "line": 10,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "20",
+                                    "offset": 28
+                                }
+                            ],
+                            "location": "ATMScenario.requestMoney(int)"
+                        },
+                        "matchedColumns": [
+                            2
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 36000,
+                            "status": "passed"
+                        },
+                        "name": "the ATM should dispense 20",
+                        "keyword": "Then ",
+                        "line": 11,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "20",
+                                    "offset": 24
+                                }
+                            ],
+                            "location": "ATMScenario.checkMoney(int)"
+                        },
+                        "matchedColumns": [
+                            3
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 1933000,
+                            "status": "skipped",
+                            "error_message": "java.lang.AssertionError: \nExpected: is <80>\n     got: <90>\n\n\tat org.junit.Assert.assertThat(Assert.java:780)\n\tat org.junit.Assert.assertThat(Assert.java:738)\n\tat net.masterthought.example.ATMScenario.checkBalance(ATMScenario.java:69)\n\tat ✽.And the account balance should be 90(net/masterthought/example/ATMK.feature:12)\n"
+                        },
+                        "name": "the account balance should be 90",
+                        "keyword": "And ",
+                        "line": 12,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "90",
+                                    "offset": 30
+                                }
+                            ],
+                            "location": "ATMScenario.checkBalance(int)"
+                        },
+                        "matchedColumns": [
+                            4
+                        ],
+                        "embeddings": [
+                            {
+                                "mime_type": "image/png",
+                                "data": "",
+                                "name": "Some PNG image"
+                            },
+                            {
+                                "mime_type": "image/jpeg",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "text/plain",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "text/html",
+                                "data": "",
+                                "name": "Some HTML embedding"
+                            },
+                            {
+                                "mime_type": "text/xml",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "image/svg+xml",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "js",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "text/plain",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "text/csv",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "video/mp4",
+                                "data": ""
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "status": "pending"
+                        },
+                        "name": "the card should be returned",
+                        "keyword": "And ",
+                        "line": 13,
+                        "match": {
+                            "location": "ATMScenario.cardShouldBeReturned()"
+                        },
+                        "embeddings": [
+                            {
+                                "mime_type": "application/json",
+                                "data": ""
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "status": "skipped"
+                        },
+                        "name": "its not implemented",
+                        "keyword": "And ",
+                        "line": 14,
+                        "match": {
+                            "location": "ATMScenario.its_not_implemented()"
+                        },
+                        "output": [
+                            [
+                                "Could not connect to the server @Rocky@"
+                            ],
+                            [
+                                "Could not connect to the server @Mike@"
+                            ]
+                        ]
+                    },
+                    {
+                        "result": {
+                            "status": "failed"
+                        },
+                        "name": "the card is valid",
+                        "keyword": "And ",
+                        "line": 15,
+                        "match": {
+                            "location": "ATMScenario.createCreditCard()"
+                        },
+                        "output": [
+                            "Checkpoints",
+                            232
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 90000000,
+                            "status": "ambiguous"
+                        },
+                        "name": "the card should be returned",
+                        "keyword": "And ",
+                        "line": 29,
+                        "match": {
+                            "location": "ATMScenario.cardShouldBeReturned()"
+                        }
+                    }
+                ],
+                "type": "scenario",
+                "after": [
+                    {
+                        "result": {
+                            "duration": 64700000,
+                            "status": "undefined",
+                            "error_message": "Undefined step"
+                        },
+                        "match": {
+                            "location": "any.error()"
+                        },
+                        "embeddings": [
+                            {
+                                "mime_type": "image/png",
+                                "data": ""
+                            }
+                        ]
+                    }
+                ]
+            },
+            {
+                "id": "account-holder-withdraws-more-cash;clean-up",
+                "name": "Clean-up",
+                "keyword": "Scenario",
+                "line": 31,
+                "steps": [
+                    {
+                        "result": {
+                            "duration": 560000,
+                            "status": "passed"
+                        },
+                        "name": "Stream closing",
+                        "keyword": "Given ",
+                        "line": 32
+                    }
+                ],
+                "type": "scenario"
+            },
+            {
+                "id": "undefined-result",
+                "name": "This step has no result...",
+                "keyword": "Scenario",
+                "line": 35,
+                "steps": [
+                    {
+                        "name": " - even it should",
+                        "keyword": "Given ",
+                        "line": 36
+                    }
+                ],
+                "type": "scenario"
+            }
+        ],
+        "uri": "net/masterthought/example/ATMK.feature"
+    }
+]
diff --git a/testlib/src/main/resources/json/cucumberJsonSampleGsonBefore.json b/testlib/src/main/resources/json/cucumberJsonSampleGsonBefore.json
new file mode 100644
index 0000000000..8250630cf7
--- /dev/null
+++ b/testlib/src/main/resources/json/cucumberJsonSampleGsonBefore.json
@@ -0,0 +1,660 @@
+[
+    {
+        "id": "account-holder-withdraws-cash",
+        "tags": [
+            {
+                "name": "@featureTag",
+                "line": 1
+            }
+        ],
+        "description": "This is description of the feature",
+        "name": "1st feature",
+        "keyword": "Feature",
+        "line": 2,
+        "elements": [
+            {
+                "description": "Perfect background",
+                "name": "Activate Credit Card",
+                "keyword": "Background",
+                "line": 7,
+                "steps": [
+                    {
+                        "result": {
+                            "duration": 99107447000,
+                            "status": "passed"
+                        },
+                        "name": "I have a new credit card",
+                        "keyword": "Given ",
+                        "line": 8,
+                        "match": {
+                            "location": "ATMScenario.I_have_a_new_credit_card()"
+                        },
+                        "embeddings": [
+                            {
+                                "mime_type": "image/url",
+                                "data": ""
+                            },
+                            {
+                                "data": "",
+                                "media": {
+                                    "type": "text/plain"
+                                }
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 9520000,
+                            "status": "passed"
+                        },
+                        "name": "My credit card is described as follow:",
+                        "keyword": "And ",
+                        "line": 9,
+                        "match": {
+                            "location": "ATMScenario.My_credit_card_is_described_as_follow"
+                        },
+                        "doc_string": {
+                            "content_type": "",
+                            "line": 10,
+                            "value": "{\n\"issuer\": {\n\"name\": \"Real Bank Inc.\",\n\"isn:\": \"RB55800093842N\"\n},\n\"card_number\": \"4896 0215 8478 6325\",\n\"holder\": \"A guy\"\n}"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 7040000,
+                            "status": "passed"
+                        },
+                        "name": "I confirm my pin number",
+                        "keyword": "When ",
+                        "line": 18,
+                        "match": {
+                            "location": "ATMScenario.I_confirm_my_pin_number()"
+                        },
+                        "rows": [
+                            {
+                                "cells": [
+                                    "Müller",
+                                    "Deutschland"
+                                ],
+                                "line": 2
+                            },
+                            {
+                                "cells": [
+                                    "Nováková",
+                                    "Česko"
+                                ],
+                                "line": 3
+                            },
+                            {
+                                "cells": [
+                                    "Kovačević",
+                                    "Hrvatska"
+                                ],
+                                "line": 4
+                            },
+                            {
+                                "cells": [
+                                    "Παπαδόπουλος",
+                                    "Παπαδόπουλος"
+                                ],
+                                "line": 5
+                            },
+                            {
+                                "cells": [
+                                    "罗/羅",
+                                    "中國"
+                                ],
+                                "line": 6
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 111111,
+                            "status": "passed"
+                        },
+                        "name": "the card should be activated",
+                        "keyword": "Then ",
+                        "line": 19,
+                        "match": {
+                            "location": "ATMScenario.the_card_should_be_activated()"
+                        }
+                    }
+                ],
+                "type": "background"
+            },
+            {
+                "id": "account-holder-withdraws-cash;account-has-\u0027sufficient-funds\u0027;;2",
+                "tags": [
+                    {
+                        "name": "@fast",
+                        "line": 21
+                    },
+                    {
+                        "name": "@featureTag",
+                        "line": 1
+                    },
+                    {
+                        "name": "@checkout",
+                        "line": 21
+                    }
+                ],
+                "description": "Account holder withdraws cash",
+                "name": "Account has <sufficient funds>",
+                "keyword": "Scenario Outline",
+                "line": 33,
+                "steps": [
+                    {
+                        "result": {
+                            "duration": 17007000,
+                            "status": "passed"
+                        },
+                        "name": "the account balance is 100",
+                        "keyword": "Given ",
+                        "line": 23,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 23
+                                }
+                            ],
+                            "location": "ATMScenario.createAccount(int)"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 33444444,
+                            "status": "passed"
+                        },
+                        "name": "the card is valid",
+                        "keyword": "And ",
+                        "line": 24,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "",
+                                    "offset": 0
+                                }
+                            ],
+                            "location": "ATMScenario.createCreditCard()"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 44333333,
+                            "status": "passed"
+                        },
+                        "name": "100 is contained in the machine",
+                        "keyword": "And ",
+                        "line": 25,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 0
+                                }
+                            ],
+                            "location": "ATMScenario.createATM(int)"
+                        },
+                        "matchedColumns": [
+                            1
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 11000001,
+                            "status": "passed"
+                        },
+                        "name": "the Account Holder requests 10, entering PIN 1234",
+                        "keyword": "When ",
+                        "line": 26,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "10",
+                                    "offset": 28
+                                },
+                                {
+                                    "val": "1234",
+                                    "offset": 45
+                                }
+                            ],
+                            "location": "ATMScenario.requestMoney(int)"
+                        },
+                        "matchedColumns": [
+                            2
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 3220000,
+                            "status": "passed"
+                        },
+                        "name": "the ATM should dispense 10 monetary units",
+                        "keyword": "Then ",
+                        "line": 27,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "10",
+                                    "offset": 24
+                                },
+                                {
+                                    "val": "",
+                                    "offset": 0
+                                }
+                            ],
+                            "location": "ATMScenario.checkMoney(int)"
+                        },
+                        "matchedColumns": [
+                            3
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 30000000,
+                            "status": "passed"
+                        },
+                        "name": "the account balance should be 90",
+                        "keyword": "And ",
+                        "line": 28,
+                        "arguments": [
+                            {
+                                "rows": [
+                                    {
+                                        "cells": [
+                                            "max",
+                                            "min"
+                                        ]
+                                    },
+                                    {
+                                        "cells": [
+                                            "20",
+                                            "3"
+                                        ]
+                                    }
+                                ]
+                            }
+                        ],
+                        "match": {
+                            "location": "ATMScenario.checkBalance(int)"
+                        },
+                        "matchedColumns": [
+                            2
+                        ]
+                    }
+                ],
+                "type": "scenario",
+                "after": [
+                    {
+                        "result": {
+                            "duration": 60744700,
+                            "status": "passed",
+                            "error_message": "Completed"
+                        },
+                        "match": {
+                            "location": "MachineFactory.timeout()"
+                        }
+                    }
+                ]
+            }
+        ],
+        "uri": "net/masterthought/example(s)/ATM:東京.feature"
+    },
+    {
+        "id": "account-holder-withdraws-more-cash",
+        "description": "As an Account Holder\nI want to withdraw cash from an ATM,<br/>so that I can get money when the bank is closed",
+        "name": "Second feature",
+        "keyword": "Feature",
+        "line": 1,
+        "elements": [
+            {
+                "id": "account-holder-withdraws-more-cash;account-has-sufficient-funds;;2",
+                "tags": [
+                    {
+                        "name": "@checkout",
+                        "line": 101
+                    }
+                ],
+                "before": [
+                    {
+                        "output": [
+                            "System version: beta3"
+                        ],
+                        "result": {
+                            "duration": 10744700,
+                            "status": "passed"
+                        },
+                        "match": {
+                            "location": "MachineFactory.findCashMachine()"
+                        }
+                    },
+                    {
+                        "result": {
+                            "duration": 1000001,
+                            "status": "failed",
+                            "error_message": "   \n"
+                        },
+                        "match": {
+                            "location": "MachineFactory.wait()"
+                        }
+                    }
+                ],
+                "description": "Account holder withdraws more cash",
+                "name": "Account may not have sufficient funds",
+                "keyword": "Scenario Outline",
+                "line": 19,
+                "steps": [
+                    {
+                        "result": {
+                            "status": "undefined"
+                        },
+                        "name": "the account balance is 100",
+                        "keyword": "Given ",
+                        "line": 7,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 23
+                                },
+                                {}
+                            ]
+                        },
+                        "matchedColumns": [
+                            0
+                        ],
+                        "before": [
+                            {
+                                "embeddings": [
+                                    {
+                                        "mime_type": "text/plain",
+                                        "data": ""
+                                    }
+                                ],
+                                "result": {
+                                    "duration": 410802047,
+                                    "status": "failed"
+                                }
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 13000,
+                            "status": "passed"
+                        },
+                        "name": "the card is valid",
+                        "keyword": "And ",
+                        "line": 8,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "",
+                                    "offset": 17
+                                }
+                            ],
+                            "location": "ATMScenario.createCreditCard()"
+                        },
+                        "after": [
+                            {
+                                "result": {
+                                    "duration": 410802048,
+                                    "status": "passed"
+                                },
+                                "match": {
+                                    "location": "StepHook.afterStep()"
+                                }
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 36000,
+                            "status": "passed"
+                        },
+                        "name": "the machine contains 100",
+                        "keyword": "And ",
+                        "line": 9,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "100",
+                                    "offset": 21
+                                }
+                            ],
+                            "location": "ATMScenario.createATM(int)"
+                        },
+                        "matchedColumns": [
+                            1
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 32000,
+                            "status": "passed"
+                        },
+                        "name": "the Account Holder requests 20",
+                        "keyword": "When ",
+                        "line": 10,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "20",
+                                    "offset": 28
+                                }
+                            ],
+                            "location": "ATMScenario.requestMoney(int)"
+                        },
+                        "matchedColumns": [
+                            2
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 36000,
+                            "status": "passed"
+                        },
+                        "name": "the ATM should dispense 20",
+                        "keyword": "Then ",
+                        "line": 11,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "20",
+                                    "offset": 24
+                                }
+                            ],
+                            "location": "ATMScenario.checkMoney(int)"
+                        },
+                        "matchedColumns": [
+                            3
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 1933000,
+                            "status": "skipped",
+                            "error_message": "java.lang.AssertionError: \nExpected: is \u003c80\u003e\n     got: \u003c90\u003e\n\n\tat org.junit.Assert.assertThat(Assert.java:780)\n\tat org.junit.Assert.assertThat(Assert.java:738)\n\tat net.masterthought.example.ATMScenario.checkBalance(ATMScenario.java:69)\n\tat ✽.And the account balance should be 90(net/masterthought/example/ATMK.feature:12)\n"
+                        },
+                        "name": "the account balance should be 90",
+                        "keyword": "And ",
+                        "line": 12,
+                        "match": {
+                            "arguments": [
+                                {
+                                    "val": "90",
+                                    "offset": 30
+                                }
+                            ],
+                            "location": "ATMScenario.checkBalance(int)"
+                        },
+                        "matchedColumns": [
+                            4
+                        ],
+                        "embeddings": [
+                            {
+                                "mime_type": "image/png",
+                                "data": "",
+                                "name": "Some PNG image"
+                            },
+                            {
+                                "mime_type": "image/jpeg",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "text/plain",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "text/html",
+                                "data": "",
+                                "name": "Some HTML embedding"
+                            },
+                            {
+                                "mime_type": "text/xml",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "image/svg+xml",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "js",
+                                "data": ""
+                            },
+                            {
+                              "mime_type": "text/plain",
+                              "data": ""
+                            },
+                            {
+                                "mime_type": "text/csv",
+                                "data": ""
+                            },
+                            {
+                                "mime_type": "video/mp4",
+                                "data": ""
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "status": "pending"
+                        },
+                        "name": "the card should be returned",
+                        "keyword": "And ",
+                        "line": 13,
+                        "match": {
+                            "location": "ATMScenario.cardShouldBeReturned()"
+                        },
+                        "embeddings": [
+                            {
+                                "mime_type": "application/json",
+                                "data": ""
+                            }
+                        ]
+                    },
+                    {
+                        "result": {
+                            "status": "skipped"
+                        },
+                        "name": "its not implemented",
+                        "keyword": "And ",
+                        "line": 14,
+                        "match": {
+                            "location": "ATMScenario.its_not_implemented()"
+                        },
+                        "output": [
+                            [
+                                "Could not connect to the server @Rocky@"
+                            ],
+                            [
+                                "Could not connect to the server @Mike@"
+                            ]
+                        ]
+                    },
+                    {
+                        "result": {
+                            "status": "failed"
+                        },
+                        "name": "the card is valid",
+                        "keyword": "And ",
+                        "line": 15,
+                        "match": {
+                            "location": "ATMScenario.createCreditCard()"
+                        },
+                        "output": [
+                            "Checkpoints",
+                            232
+                        ]
+                    },
+                    {
+                        "result": {
+                            "duration": 90000000,
+                            "status": "ambiguous"
+                        },
+                        "name": "the card should be returned",
+                        "keyword": "And ",
+                        "line": 29,
+                        "match": {
+                            "location": "ATMScenario.cardShouldBeReturned()"
+                        }
+                    }
+                ],
+                "type": "scenario",
+                "after": [
+                    {
+                        "result": {
+                            "duration": 64700000,
+                            "status": "undefined",
+                            "error_message": "Undefined step"
+                        },
+                        "match": {
+                            "location": "any.error()"
+                        },
+                        "embeddings": [
+                            {
+                                "mime_type": "image/png",
+                                "data": ""
+                            }
+                        ]
+                    }
+                ]
+            },
+            {
+                "id": "account-holder-withdraws-more-cash;clean-up",
+                "name": "Clean-up",
+                "keyword": "Scenario",
+                "line": 31,
+                "steps": [
+                    {
+                        "result": {
+                            "duration": 560000,
+                            "status": "passed"
+                        },
+                        "name": "Stream closing",
+                        "keyword": "Given ",
+                        "line": 32
+                    }
+                ],
+                "type": "scenario"
+            },
+            {
+                "id": "undefined-result",
+                "name": "This step has no result...",
+                "keyword": "Scenario",
+                "line": 35,
+                "steps": [
+                    {
+                        "name": " - even it should",
+                        "keyword": "Given ",
+                        "line": 36
+                    }
+                ],
+                "type": "scenario"
+            }
+        ],
+        "uri": "net/masterthought/example/ATMK.feature"
+    }
+]
diff --git a/testlib/src/main/resources/json/escapeHtmlGsonAfter.json b/testlib/src/main/resources/json/escapeHtmlGsonAfter.json
new file mode 100644
index 0000000000..f83692da2a
--- /dev/null
+++ b/testlib/src/main/resources/json/escapeHtmlGsonAfter.json
@@ -0,0 +1,4 @@
+{
+    "escapedHtml": "\u003ca href\u003d\u0027https://www.google.com/search?q\u003ddiffplug-spotless\u0026tbm\u003disch\u0027\u003eSee some pictures!\u003c\\a\u003e",
+    "rawHtml": "\u003ca href\u003d\u0027https://www.google.com/search?q\u003ddiffplug-spotless\u0026tbm\u003disch\u0027\u003eSee some pictures!\u003c\\a\u003e"
+}
diff --git a/testlib/src/main/resources/json/escapeHtmlGsonAfterDisabled.json b/testlib/src/main/resources/json/escapeHtmlGsonAfterDisabled.json
new file mode 100644
index 0000000000..fe033341f8
--- /dev/null
+++ b/testlib/src/main/resources/json/escapeHtmlGsonAfterDisabled.json
@@ -0,0 +1,4 @@
+{
+    "escapedHtml": "<a href='https://www.google.com/search?q=diffplug-spotless&tbm=isch'>See some pictures!<\\a>",
+    "rawHtml": "<a href='https://www.google.com/search?q=diffplug-spotless&tbm=isch'>See some pictures!<\\a>"
+}
diff --git a/testlib/src/main/resources/json/escapeHtmlGsonBefore.json b/testlib/src/main/resources/json/escapeHtmlGsonBefore.json
new file mode 100644
index 0000000000..400e862d99
--- /dev/null
+++ b/testlib/src/main/resources/json/escapeHtmlGsonBefore.json
@@ -0,0 +1,4 @@
+{
+    "escapedHtml": "\u003ca href\u003d\u0027https://www.google.com/search?q\u003ddiffplug-spotless\u0026tbm\u003disch\u0027\u003eSee some pictures!\u003c\\a\u003e",
+    "rawHtml": "<a href='https://www.google.com/search?q=diffplug-spotless&tbm=isch'>See some pictures!<\\a>"
+}
diff --git a/testlib/src/main/resources/json/objectWithNullGsonAfter.json b/testlib/src/main/resources/json/objectWithNullGsonAfter.json
new file mode 100644
index 0000000000..368632dd8a
--- /dev/null
+++ b/testlib/src/main/resources/json/objectWithNullGsonAfter.json
@@ -0,0 +1,4 @@
+{
+    "value": null,
+    "another": 1
+}
diff --git a/testlib/src/main/resources/json/objectWithNullGsonBefore.json b/testlib/src/main/resources/json/objectWithNullGsonBefore.json
new file mode 100644
index 0000000000..f68567c97c
--- /dev/null
+++ b/testlib/src/main/resources/json/objectWithNullGsonBefore.json
@@ -0,0 +1,4 @@
+{
+"value": null,
+"another": 1
+}
diff --git a/testlib/src/main/resources/json/sortByKeysAfter.json b/testlib/src/main/resources/json/sortByKeysAfter.json
new file mode 100644
index 0000000000..c4a48de2f2
--- /dev/null
+++ b/testlib/src/main/resources/json/sortByKeysAfter.json
@@ -0,0 +1,19 @@
+{
+    "A": 1,
+    "X": 2,
+    "_arraysNotSorted": [
+        3,
+        2,
+        1
+    ],
+    "a": 3,
+    "c": 4,
+    "x": 5,
+    "z": {
+        "A": 1,
+        "X": 2,
+        "a": 3,
+        "c": 4,
+        "x": 5
+    }
+}
diff --git a/testlib/src/main/resources/json/sortByKeysAfterDisabled.json b/testlib/src/main/resources/json/sortByKeysAfterDisabled.json
new file mode 100644
index 0000000000..de7462bb98
--- /dev/null
+++ b/testlib/src/main/resources/json/sortByKeysAfterDisabled.json
@@ -0,0 +1,19 @@
+{
+    "z": {
+        "c": 4,
+        "x": 5,
+        "X": 2,
+        "A": 1,
+        "a": 3
+    },
+    "c": 4,
+    "x": 5,
+    "X": 2,
+    "A": 1,
+    "a": 3,
+    "_arraysNotSorted": [
+        3,
+        2,
+        1
+    ]
+}
diff --git a/testlib/src/main/resources/json/sortByKeysBefore.json b/testlib/src/main/resources/json/sortByKeysBefore.json
new file mode 100644
index 0000000000..de7462bb98
--- /dev/null
+++ b/testlib/src/main/resources/json/sortByKeysBefore.json
@@ -0,0 +1,19 @@
+{
+    "z": {
+        "c": 4,
+        "x": 5,
+        "X": 2,
+        "A": 1,
+        "a": 3
+    },
+    "c": 4,
+    "x": 5,
+    "X": 2,
+    "A": 1,
+    "a": 3,
+    "_arraysNotSorted": [
+        3,
+        2,
+        1
+    ]
+}
diff --git a/testlib/src/test/java/com/diffplug/spotless/json/JsonFormatterStepCommonTests.java b/testlib/src/test/java/com/diffplug/spotless/json/JsonFormatterStepCommonTests.java
new file mode 100644
index 0000000000..9ee76f994c
--- /dev/null
+++ b/testlib/src/test/java/com/diffplug/spotless/json/JsonFormatterStepCommonTests.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.jupiter.api.Test;
+
+import com.diffplug.spotless.*;
+
+public abstract class JsonFormatterStepCommonTests {
+
+	protected static final int INDENT = 4;
+
+	@Test
+	void cannotProvideNullProvisioner() {
+		assertThatThrownBy(() -> createFormatterStep(INDENT, null))
+				.isInstanceOf(NullPointerException.class)
+				.hasMessage("provisioner cannot be null");
+	}
+
+	@Test
+	void handlesNestedObject() throws Exception {
+		doWithResource("nestedObject");
+	}
+
+	@Test
+	void handlesSingletonArray() throws Exception {
+		doWithResource("singletonArray");
+	}
+
+	@Test
+	void handlesEmptyFile() throws Exception {
+		doWithResource("empty");
+	}
+
+	@Test
+	void canSetCustomIndentationLevel() throws Exception {
+		FormatterStep step = createFormatterStep(6, TestProvisioner.mavenCentral());
+		StepHarness stepHarness = StepHarness.forStep(step);
+
+		String before = "json/singletonArrayBefore.json";
+		String after = "json/singletonArrayAfter6Spaces.json";
+		stepHarness.testResource(before, after);
+	}
+
+	@Test
+	void canSetIndentationLevelTo0() throws Exception {
+		FormatterStep step = createFormatterStep(0, TestProvisioner.mavenCentral());
+		StepHarness stepHarness = StepHarness.forStep(step);
+
+		String before = "json/singletonArrayBefore.json";
+		String after = "json/singletonArrayAfter0Spaces.json";
+		stepHarness.testResource(before, after);
+	}
+
+	@Test
+	void equality() {
+		new SerializableEqualityTester() {
+			int spaces = 0;
+
+			@Override
+			protected void setupTest(API api) {
+				// no changes, are the same
+				api.areDifferentThan();
+
+				// with different spacing
+				spaces = 1;
+				api.areDifferentThan();
+			}
+
+			@Override
+			protected FormatterStep create() {
+				return createFormatterStep(spaces, TestProvisioner.mavenCentral());
+			}
+		}.testEquals();
+	}
+
+	protected abstract FormatterStep createFormatterStep(int indent, Provisioner provisioner);
+
+	protected StepHarness getStepHarness() {
+		return StepHarness.forStep(createFormatterStep(INDENT, TestProvisioner.mavenCentral()));
+	}
+
+	protected void doWithResource(String name) throws Exception {
+		String before = String.format("json/%sBefore.json", name);
+		String after = String.format("json/%sAfter.json", name);
+		getStepHarness().testResource(before, after);
+	}
+
+}
diff --git a/testlib/src/test/java/com/diffplug/spotless/json/JsonSimpleStepTest.java b/testlib/src/test/java/com/diffplug/spotless/json/JsonSimpleStepTest.java
index 4085744593..b4f98e69ba 100644
--- a/testlib/src/test/java/com/diffplug/spotless/json/JsonSimpleStepTest.java
+++ b/testlib/src/test/java/com/diffplug/spotless/json/JsonSimpleStepTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 DiffPlug
+ * Copyright 2021-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,61 +19,33 @@
 
 import org.junit.jupiter.api.Test;
 
-import com.diffplug.spotless.FormatterStep;
-import com.diffplug.spotless.SerializableEqualityTester;
-import com.diffplug.spotless.StepHarness;
-import com.diffplug.spotless.TestProvisioner;
+import com.diffplug.spotless.*;
 
-class JsonSimpleStepTest {
-
-	private static final int INDENT = 4;
-
-	private final FormatterStep step = JsonSimpleStep.create(INDENT, TestProvisioner.mavenCentral());
-	private final StepHarness stepHarness = StepHarness.forStep(step);
-
-	@Test
-	void cannotProvidedNullProvisioner() {
-		assertThatThrownBy(() -> JsonSimpleStep.create(INDENT, null)).isInstanceOf(NullPointerException.class).hasMessage("provisioner cannot be null");
-	}
+class JsonSimpleStepTest extends JsonFormatterStepCommonTests {
 
 	@Test
 	void handlesSingletonObject() throws Exception {
-		doWithResource(stepHarness, "singletonObject");
+		doWithResource("singletonObject");
 	}
 
 	@Test
 	void handlesSingletonObjectWithArray() throws Exception {
-		doWithResource(stepHarness, "singletonObjectWithArray");
-	}
-
-	@Test
-	void handlesNestedObject() throws Exception {
-		doWithResource(stepHarness, "nestedObject");
-	}
-
-	@Test
-	void handlesSingletonArray() throws Exception {
-		doWithResource(stepHarness, "singletonArray");
-	}
-
-	@Test
-	void handlesEmptyFile() throws Exception {
-		doWithResource(stepHarness, "empty");
+		doWithResource("singletonObjectWithArray");
 	}
 
 	@Test
 	void handlesComplexNestedObject() throws Exception {
-		doWithResource(stepHarness, "cucumberJsonSample");
+		doWithResource("cucumberJsonSample");
 	}
 
 	@Test
 	void handlesObjectWithNull() throws Exception {
-		doWithResource(stepHarness, "objectWithNull");
+		doWithResource("objectWithNull");
 	}
 
 	@Test
 	void handlesInvalidJson() {
-		assertThatThrownBy(() -> doWithResource(stepHarness, "invalidJson"))
+		assertThatThrownBy(() -> doWithResource("invalidJson"))
 				.isInstanceOf(AssertionError.class)
 				.hasMessage("Unable to format JSON")
 				.hasRootCauseMessage("Expected a ',' or '}' at 9 [character 0 line 3]");
@@ -81,57 +53,14 @@ void handlesInvalidJson() {
 
 	@Test
 	void handlesNotJson() {
-		assertThatThrownBy(() -> doWithResource(stepHarness, "notJson"))
+		assertThatThrownBy(() -> doWithResource("notJson"))
 				.isInstanceOf(AssertionError.class)
 				.hasMessage("Unable to determine JSON type, expected a '{' or '[' but found '#'")
 				.hasNoCause();
 	}
 
-	@Test
-	void canSetCustomIndentationLevel() throws Exception {
-		FormatterStep step = JsonSimpleStep.create(6, TestProvisioner.mavenCentral());
-		StepHarness stepHarness = StepHarness.forStep(step);
-
-		String before = "json/singletonArrayBefore.json";
-		String after = "json/singletonArrayAfter6Spaces.json";
-		stepHarness.testResource(before, after);
-	}
-
-	@Test
-	void canSetIndentationLevelTo0() throws Exception {
-		FormatterStep step = JsonSimpleStep.create(0, TestProvisioner.mavenCentral());
-		StepHarness stepHarness = StepHarness.forStep(step);
-
-		String before = "json/singletonArrayBefore.json";
-		String after = "json/singletonArrayAfter0Spaces.json";
-		stepHarness.testResource(before, after);
-	}
-
-	@Test
-	void equality() {
-		new SerializableEqualityTester() {
-			int spaces = 0;
-
-			@Override
-			protected void setupTest(API api) {
-				// no changes, are the same
-				api.areDifferentThan();
-
-				// with different spacing
-				spaces = 1;
-				api.areDifferentThan();
-			}
-
-			@Override
-			protected FormatterStep create() {
-				return JsonSimpleStep.create(spaces, TestProvisioner.mavenCentral());
-			}
-		}.testEquals();
-	}
-
-	private static void doWithResource(StepHarness stepHarness, String name) throws Exception {
-		String before = String.format("json/%sBefore.json", name);
-		String after = String.format("json/%sAfter.json", name);
-		stepHarness.testResource(before, after);
+	@Override
+	protected FormatterStep createFormatterStep(int indent, Provisioner provisioner) {
+		return JsonSimpleStep.create(indent, provisioner);
 	}
 }
diff --git a/testlib/src/test/java/com/diffplug/spotless/json/gson/GsonStepTest.java b/testlib/src/test/java/com/diffplug/spotless/json/gson/GsonStepTest.java
new file mode 100644
index 0000000000..cf1fd10752
--- /dev/null
+++ b/testlib/src/test/java/com/diffplug/spotless/json/gson/GsonStepTest.java
@@ -0,0 +1,99 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.json.gson;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import org.junit.jupiter.api.Test;
+
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.Provisioner;
+import com.diffplug.spotless.StepHarness;
+import com.diffplug.spotless.TestProvisioner;
+import com.diffplug.spotless.json.JsonFormatterStepCommonTests;
+
+public class GsonStepTest extends JsonFormatterStepCommonTests {
+
+	private static final String DEFAULT_VERSION = "2.8.9";
+
+	@Test
+	void handlesComplexNestedObject() throws Exception {
+		doWithResource("cucumberJsonSampleGson");
+	}
+
+	@Test
+	void handlesObjectWithNull() throws Exception {
+		doWithResource("objectWithNullGson");
+	}
+
+	@Test
+	void handlesInvalidJson() {
+		assertThatThrownBy(() -> doWithResource("invalidJson"))
+				.isInstanceOf(AssertionError.class)
+				.hasMessage("Unable to format JSON")
+				.hasRootCauseMessage("End of input at line 3 column 1 path $.a");
+	}
+
+	@Test
+	void handlesNotJson() {
+		assertThatThrownBy(() -> doWithResource("notJson"))
+				.isInstanceOf(AssertionError.class)
+				.hasMessage("Unable to format JSON")
+				.hasNoCause();
+	}
+
+	@Test
+	void handlesSortingWhenSortByKeyEnabled() throws Exception {
+		FormatterStep step = GsonStep.create(INDENT, true, false, DEFAULT_VERSION, TestProvisioner.mavenCentral());
+		StepHarness stepHarness = StepHarness.forStep(step);
+		stepHarness.testResource("json/sortByKeysBefore.json", "json/sortByKeysAfter.json");
+	}
+
+	@Test
+	void doesNoSortingWhenSortByKeyDisabled() throws Exception {
+		FormatterStep step = GsonStep.create(INDENT, false, false, DEFAULT_VERSION, TestProvisioner.mavenCentral());
+		StepHarness.forStep(step)
+				.testResource("json/sortByKeysBefore.json", "json/sortByKeysAfterDisabled.json");
+	}
+
+	@Test
+	void handlesHtmlEscapeWhenEnabled() throws Exception {
+		FormatterStep step = GsonStep.create(INDENT, false, true, DEFAULT_VERSION, TestProvisioner.mavenCentral());
+		StepHarness.forStep(step)
+				.testResource("json/escapeHtmlGsonBefore.json", "json/escapeHtmlGsonAfter.json");
+	}
+
+	@Test
+	void writesRawHtmlWhenHtmlEscapeDisabled() throws Exception {
+		FormatterStep step = GsonStep.create(INDENT, false, false, DEFAULT_VERSION, TestProvisioner.mavenCentral());
+		StepHarness.forStep(step)
+				.testResource("json/escapeHtmlGsonBefore.json", "json/escapeHtmlGsonAfterDisabled.json");
+	}
+
+	@Test
+	void handlesVersionIncompatibility() {
+		FormatterStep step = GsonStep.create(INDENT, false, false, "1.7", TestProvisioner.mavenCentral());
+		StepHarness stepHarness = StepHarness.forStep(step);
+		assertThatThrownBy(() -> stepHarness.testResource("json/cucumberJsonSampleGsonBefore.json", "json/cucumberJsonSampleGsonAfter.json"))
+				.isInstanceOf(IllegalStateException.class)
+				.hasMessage("There was a problem interacting with Gson; maybe you set an incompatible version?");
+	}
+
+	@Override
+	protected FormatterStep createFormatterStep(int indent, Provisioner provisioner) {
+		return GsonStep.create(indent, false, false, DEFAULT_VERSION, provisioner);
+	}
+}