diff --git a/openapi-raw.yaml b/openapi-raw.yaml
index 2b8c48a4a..d6d0632f3 100644
--- a/openapi-raw.yaml
+++ b/openapi-raw.yaml
@@ -11305,7 +11305,6 @@ components:
         - event_time
         - event_type
         - event_hash
-        - event_metadata
       properties:
         event_time:
           description: '_t__EventCallbackRequestEvent::EVENT_TIME'
diff --git a/openapi-sdk.yaml b/openapi-sdk.yaml
index 41f9a839f..4bf544b46 100644
--- a/openapi-sdk.yaml
+++ b/openapi-sdk.yaml
@@ -12225,7 +12225,6 @@ components:
         - event_time
         - event_type
         - event_hash
-        - event_metadata
       properties:
         event_time:
           description: 'Time the event was created (using Unix time).'
diff --git a/openapi.yaml b/openapi.yaml
index 7d056f75b..bee7073fa 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -11685,7 +11685,6 @@ components:
         - event_time
         - event_type
         - event_hash
-        - event_metadata
       properties:
         event_time:
           description: 'Time the event was created (using Unix time).'
diff --git a/sdks/dotnet/docs/EventCallbackRequestEvent.md b/sdks/dotnet/docs/EventCallbackRequestEvent.md
index 47819b7c7..98884f129 100644
--- a/sdks/dotnet/docs/EventCallbackRequestEvent.md
+++ b/sdks/dotnet/docs/EventCallbackRequestEvent.md
@@ -8,7 +8,7 @@ Name | Type | Description | Notes
 **EventTime** | **string** |  Time the event was created (using Unix time).  | 
 **EventType** | **string** |  Type of callback event that was triggered.  | 
 **EventHash** | **string** |  Generated hash used to verify source of event data.  | 
-**EventMetadata** | [**EventCallbackRequestEventMetadata**](EventCallbackRequestEventMetadata.md) |    | 
+**EventMetadata** | [**EventCallbackRequestEventMetadata**](EventCallbackRequestEventMetadata.md) |    | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/sdks/dotnet/src/Dropbox.Sign.Test/EventCallbackHelperTests.cs b/sdks/dotnet/src/Dropbox.Sign.Test/EventCallbackHelperTests.cs
index bbe876147..5a213a694 100644
--- a/sdks/dotnet/src/Dropbox.Sign.Test/EventCallbackHelperTests.cs
+++ b/sdks/dotnet/src/Dropbox.Sign.Test/EventCallbackHelperTests.cs
@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using Newtonsoft.Json;
 using Xunit;
 using Dropbox.Sign.Model;
 
@@ -13,22 +12,50 @@ public class EventCallbackHelperTests
         [Fact]
         public void IsValidTest()
         {
-            var keys = new List<string>
+            var account_keys = new List<string>
             {
                 "base",
+                "base_no_metadata",
                 "account",
+                "account_no_metadata",
                 "signature_request",
+                "signature_request_no_metadata",
                 "template",
+                "template_no_metadata",
             };
 
-            foreach (var key in keys)
+            foreach (var key in account_keys)
             {
-                var requestData = TestHelper.GetJsonContents(nameof(EventCallbackHelper), key);
+                var requestData = TestHelper.GetJsonContents("EventCallbackHelper_AccountCallbacks", key);
                 var callbackEvent = EventCallbackRequest.Init(requestData.ToString());
 
                 Assert.True(EventCallbackHelper.IsValid(ApiKey, callbackEvent));
                 Assert.False(EventCallbackHelper.IsValid(Reverse(ApiKey), callbackEvent));
+                Assert.Equal(
+                    EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK,
+                    EventCallbackHelper.GetCallbackType(callbackEvent)
+                );
+            }
+            
+            var app_keys = new List<string>
+            {
+                "base",
+                "account",
+                "signature_request",
+                "template",
+            };
+
+            foreach (var key in app_keys)
+            {
+                var requestData = TestHelper.GetJsonContents("EventCallbackHelper_AppCallbacks", key);
+                var callbackEvent = EventCallbackRequest.Init(requestData.ToString());
 
+                Assert.True(EventCallbackHelper.IsValid(ApiKey, callbackEvent));
+                Assert.False(EventCallbackHelper.IsValid(Reverse(ApiKey), callbackEvent));
+                Assert.Equal(
+                    EventCallbackHelper.EVENT_TYPE_APP_CALLBACK, 
+                    EventCallbackHelper.GetCallbackType(callbackEvent)
+                );
             }
         }
 
diff --git a/sdks/dotnet/src/Dropbox.Sign/EventCallbackHelper.cs b/sdks/dotnet/src/Dropbox.Sign/EventCallbackHelper.cs
index ed1b9b931..40fa9a21b 100644
--- a/sdks/dotnet/src/Dropbox.Sign/EventCallbackHelper.cs
+++ b/sdks/dotnet/src/Dropbox.Sign/EventCallbackHelper.cs
@@ -35,7 +35,7 @@ public static string GetCallbackType(EventCallbackRequest eventCallback)
         {
             var metaData = eventCallback.Event.EventMetadata;
 
-            if (String.IsNullOrEmpty(metaData.ReportedForAppId))
+            if (metaData == null || String.IsNullOrEmpty(metaData.ReportedForAppId))
             {
                 return EVENT_TYPE_ACCOUNT_CALLBACK;
             }
diff --git a/sdks/dotnet/src/Dropbox.Sign/Model/EventCallbackRequestEvent.cs b/sdks/dotnet/src/Dropbox.Sign/Model/EventCallbackRequestEvent.cs
index 1bb377a37..16abdf345 100644
--- a/sdks/dotnet/src/Dropbox.Sign/Model/EventCallbackRequestEvent.cs
+++ b/sdks/dotnet/src/Dropbox.Sign/Model/EventCallbackRequestEvent.cs
@@ -192,7 +192,7 @@ protected EventCallbackRequestEvent() { }
         /// <param name="eventTime">Time the event was created (using Unix time). (required).</param>
         /// <param name="eventType">Type of callback event that was triggered. (required).</param>
         /// <param name="eventHash">Generated hash used to verify source of event data. (required).</param>
-        /// <param name="eventMetadata">eventMetadata (required).</param>
+        /// <param name="eventMetadata">eventMetadata.</param>
         public EventCallbackRequestEvent(string eventTime = default(string), EventTypeEnum eventType = default(EventTypeEnum), string eventHash = default(string), EventCallbackRequestEventMetadata eventMetadata = default(EventCallbackRequestEventMetadata))
         {
             
@@ -209,11 +209,6 @@ protected EventCallbackRequestEvent() { }
                 throw new ArgumentNullException("eventHash is a required property for EventCallbackRequestEvent and cannot be null");
             }
             this.EventHash = eventHash;
-            // to ensure "eventMetadata" is required (not null)
-            if (eventMetadata == null)
-            {
-                throw new ArgumentNullException("eventMetadata is a required property for EventCallbackRequestEvent and cannot be null");
-            }
             this.EventMetadata = eventMetadata;
         }
 
@@ -250,7 +245,7 @@ public static EventCallbackRequestEvent Init(string jsonData)
         /// <summary>
         /// Gets or Sets EventMetadata
         /// </summary>
-        [DataMember(Name = "event_metadata", IsRequired = true, EmitDefaultValue = true)]
+        [DataMember(Name = "event_metadata", EmitDefaultValue = true)]
         public EventCallbackRequestEventMetadata EventMetadata { get; set; }
 
         /// <summary>
diff --git a/sdks/dotnet/templates/EventCallbackHelper.cs b/sdks/dotnet/templates/EventCallbackHelper.cs
index ed1b9b931..40fa9a21b 100644
--- a/sdks/dotnet/templates/EventCallbackHelper.cs
+++ b/sdks/dotnet/templates/EventCallbackHelper.cs
@@ -35,7 +35,7 @@ public static string GetCallbackType(EventCallbackRequest eventCallback)
         {
             var metaData = eventCallback.Event.EventMetadata;
 
-            if (String.IsNullOrEmpty(metaData.ReportedForAppId))
+            if (metaData == null || String.IsNullOrEmpty(metaData.ReportedForAppId))
             {
                 return EVENT_TYPE_ACCOUNT_CALLBACK;
             }
diff --git a/sdks/java-v1/docs/EventCallbackRequestEvent.md b/sdks/java-v1/docs/EventCallbackRequestEvent.md
index 52d21dec4..b93f11035 100644
--- a/sdks/java-v1/docs/EventCallbackRequestEvent.md
+++ b/sdks/java-v1/docs/EventCallbackRequestEvent.md
@@ -11,7 +11,7 @@ Name | Type | Description | Notes
 | `eventTime`<sup>*_required_</sup> | ```String``` |  Time the event was created (using Unix time).  |  |
 | `eventType`<sup>*_required_</sup> | [```EventTypeEnum```](#EventTypeEnum) |  Type of callback event that was triggered.  |  |
 | `eventHash`<sup>*_required_</sup> | ```String``` |  Generated hash used to verify source of event data.  |  |
-| `eventMetadata`<sup>*_required_</sup> | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
+| `eventMetadata` | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
 
 
 
diff --git a/sdks/java-v1/src/main/java/com/dropbox/sign/EventCallbackHelper.java b/sdks/java-v1/src/main/java/com/dropbox/sign/EventCallbackHelper.java
index 78a914d9f..47f5a81d9 100644
--- a/sdks/java-v1/src/main/java/com/dropbox/sign/EventCallbackHelper.java
+++ b/sdks/java-v1/src/main/java/com/dropbox/sign/EventCallbackHelper.java
@@ -50,7 +50,11 @@ public static boolean isValid(String apiKey, EventCallbackRequest eventCallback)
     public static String getCallbackType(EventCallbackRequest eventCallback) {
         EventCallbackRequestEventMetadata metadata = eventCallback.getEvent().getEventMetadata();
 
-        if (metadata.getReportedForAppId() == null || metadata.getReportedForAppId().isEmpty()) {
+        if (
+            metadata == null ||
+            metadata.getReportedForAppId() == null ||
+            metadata.getReportedForAppId().isEmpty()
+        ) {
             return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
         }
 
diff --git a/sdks/java-v1/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java b/sdks/java-v1/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java
index 2d451bf7d..eb4632e55 100644
--- a/sdks/java-v1/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java
+++ b/sdks/java-v1/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java
@@ -237,10 +237,10 @@ public EventCallbackRequestEvent eventMetadata(EventCallbackRequestEventMetadata
    * Get eventMetadata
    * @return eventMetadata
   **/
-  @javax.annotation.Nonnull
-  @ApiModelProperty(required = true, value = "")
+  @javax.annotation.Nullable
+  @ApiModelProperty(value = "")
   @JsonProperty(JSON_PROPERTY_EVENT_METADATA)
-  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
 
   public EventCallbackRequestEventMetadata getEventMetadata() {
     return eventMetadata;
@@ -248,7 +248,7 @@ public EventCallbackRequestEventMetadata getEventMetadata() {
 
 
   @JsonProperty(JSON_PROPERTY_EVENT_METADATA)
-  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
   public void setEventMetadata(EventCallbackRequestEventMetadata eventMetadata) {
     this.eventMetadata = eventMetadata;
   }
diff --git a/sdks/java-v1/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java b/sdks/java-v1/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java
index 10c1cb2fc..903eb2c9c 100644
--- a/sdks/java-v1/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java
+++ b/sdks/java-v1/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java
@@ -19,20 +19,48 @@ public class EventCallbackHelperTest {
     public void testIsValid() throws Exception {
         String reverseApiKey = new StringBuilder(APIKEY).reverse().toString();
 
-        List<String> keys = Arrays.asList(
+        List<String> account_keys = Arrays.asList(
+            "base",
+            "base_no_metadata",
+            "account",
+            "account_no_metadata",
+            "signature_request",
+            "signature_request_no_metadata",
+            "template",
+            "template_no_metadata"
+        );
+
+        for (String key : account_keys) {
+            JsonNode content = TestHelper.getJsonContents("EventCallbackHelper_AccountCallbacks", key);
+
+            EventCallbackRequest callbackEvent = EventCallbackRequest.init(content.toString());
+
+            Assert.assertTrue(EventCallbackHelper.isValid(APIKEY, callbackEvent));
+            Assert.assertFalse(EventCallbackHelper.isValid(reverseApiKey, callbackEvent));
+            Assert.assertEquals(
+                EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK,
+                EventCallbackHelper.getCallbackType(callbackEvent)
+            );
+        }
+
+        List<String> app_keys = Arrays.asList(
             "base",
             "account",
             "signature_request",
             "template"
         );
 
-        for (String key : keys) {
-            JsonNode content = TestHelper.getJsonContents("EventCallbackHelper", key);
+        for (String key : app_keys) {
+            JsonNode content = TestHelper.getJsonContents("EventCallbackHelper_AppCallbacks", key);
 
             EventCallbackRequest callbackEvent = EventCallbackRequest.init(content.toString());
 
             Assert.assertTrue(EventCallbackHelper.isValid(APIKEY, callbackEvent));
             Assert.assertFalse(EventCallbackHelper.isValid(reverseApiKey, callbackEvent));
+            Assert.assertEquals(
+                EventCallbackHelper.EVENT_TYPE_APP_CALLBACK,
+                EventCallbackHelper.getCallbackType(callbackEvent)
+            );
         }
     }
 }
diff --git a/sdks/java-v1/templates/EventCallbackHelper.mustache b/sdks/java-v1/templates/EventCallbackHelper.mustache
index 6db22057d..d9e55681e 100644
--- a/sdks/java-v1/templates/EventCallbackHelper.mustache
+++ b/sdks/java-v1/templates/EventCallbackHelper.mustache
@@ -39,7 +39,11 @@ public class EventCallbackHelper {
     public static String getCallbackType(EventCallbackRequest eventCallback) {
         EventCallbackRequestEventMetadata metadata = eventCallback.getEvent().getEventMetadata();
 
-        if (metadata.getReportedForAppId() == null || metadata.getReportedForAppId().isEmpty()) {
+        if (
+            metadata == null ||
+            metadata.getReportedForAppId() == null ||
+            metadata.getReportedForAppId().isEmpty()
+        ) {
             return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
         }
 
diff --git a/sdks/java-v2/docs/EventCallbackRequestEvent.md b/sdks/java-v2/docs/EventCallbackRequestEvent.md
index 52d21dec4..b93f11035 100644
--- a/sdks/java-v2/docs/EventCallbackRequestEvent.md
+++ b/sdks/java-v2/docs/EventCallbackRequestEvent.md
@@ -11,7 +11,7 @@ Name | Type | Description | Notes
 | `eventTime`<sup>*_required_</sup> | ```String``` |  Time the event was created (using Unix time).  |  |
 | `eventType`<sup>*_required_</sup> | [```EventTypeEnum```](#EventTypeEnum) |  Type of callback event that was triggered.  |  |
 | `eventHash`<sup>*_required_</sup> | ```String``` |  Generated hash used to verify source of event data.  |  |
-| `eventMetadata`<sup>*_required_</sup> | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
+| `eventMetadata` | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
 
 
 
diff --git a/sdks/java-v2/src/main/java/com/dropbox/sign/EventCallbackHelper.java b/sdks/java-v2/src/main/java/com/dropbox/sign/EventCallbackHelper.java
index 4e97ee25f..e28824f7a 100644
--- a/sdks/java-v2/src/main/java/com/dropbox/sign/EventCallbackHelper.java
+++ b/sdks/java-v2/src/main/java/com/dropbox/sign/EventCallbackHelper.java
@@ -50,7 +50,11 @@ public static boolean isValid(String apiKey, EventCallbackRequest eventCallback)
     public static String getCallbackType(EventCallbackRequest eventCallback) {
         EventCallbackRequestEventMetadata metadata = eventCallback.getEvent().getEventMetadata();
 
-        if (metadata.getReportedForAppId() == null || metadata.getReportedForAppId().isEmpty()) {
+        if (
+            metadata == null ||
+            metadata.getReportedForAppId() == null ||
+            metadata.getReportedForAppId().isEmpty()
+        ) {
             return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
         }
 
diff --git a/sdks/java-v2/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java b/sdks/java-v2/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java
index 519046766..576fcd039 100644
--- a/sdks/java-v2/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java
+++ b/sdks/java-v2/src/main/java/com/dropbox/sign/model/EventCallbackRequestEvent.java
@@ -237,10 +237,10 @@ public EventCallbackRequestEvent eventMetadata(EventCallbackRequestEventMetadata
    * Get eventMetadata
    * @return eventMetadata
   **/
-  @jakarta.annotation.Nonnull
-  @ApiModelProperty(required = true, value = "")
+  @jakarta.annotation.Nullable
+  @ApiModelProperty(value = "")
   @JsonProperty(JSON_PROPERTY_EVENT_METADATA)
-  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
 
   public EventCallbackRequestEventMetadata getEventMetadata() {
     return eventMetadata;
@@ -248,7 +248,7 @@ public EventCallbackRequestEventMetadata getEventMetadata() {
 
 
   @JsonProperty(JSON_PROPERTY_EVENT_METADATA)
-  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
   public void setEventMetadata(EventCallbackRequestEventMetadata eventMetadata) {
     this.eventMetadata = eventMetadata;
   }
diff --git a/sdks/java-v2/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java b/sdks/java-v2/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java
index 10c1cb2fc..903eb2c9c 100644
--- a/sdks/java-v2/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java
+++ b/sdks/java-v2/src/test/java/com/dropbox/sign/EventCallbackHelperTest.java
@@ -19,20 +19,48 @@ public class EventCallbackHelperTest {
     public void testIsValid() throws Exception {
         String reverseApiKey = new StringBuilder(APIKEY).reverse().toString();
 
-        List<String> keys = Arrays.asList(
+        List<String> account_keys = Arrays.asList(
+            "base",
+            "base_no_metadata",
+            "account",
+            "account_no_metadata",
+            "signature_request",
+            "signature_request_no_metadata",
+            "template",
+            "template_no_metadata"
+        );
+
+        for (String key : account_keys) {
+            JsonNode content = TestHelper.getJsonContents("EventCallbackHelper_AccountCallbacks", key);
+
+            EventCallbackRequest callbackEvent = EventCallbackRequest.init(content.toString());
+
+            Assert.assertTrue(EventCallbackHelper.isValid(APIKEY, callbackEvent));
+            Assert.assertFalse(EventCallbackHelper.isValid(reverseApiKey, callbackEvent));
+            Assert.assertEquals(
+                EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK,
+                EventCallbackHelper.getCallbackType(callbackEvent)
+            );
+        }
+
+        List<String> app_keys = Arrays.asList(
             "base",
             "account",
             "signature_request",
             "template"
         );
 
-        for (String key : keys) {
-            JsonNode content = TestHelper.getJsonContents("EventCallbackHelper", key);
+        for (String key : app_keys) {
+            JsonNode content = TestHelper.getJsonContents("EventCallbackHelper_AppCallbacks", key);
 
             EventCallbackRequest callbackEvent = EventCallbackRequest.init(content.toString());
 
             Assert.assertTrue(EventCallbackHelper.isValid(APIKEY, callbackEvent));
             Assert.assertFalse(EventCallbackHelper.isValid(reverseApiKey, callbackEvent));
+            Assert.assertEquals(
+                EventCallbackHelper.EVENT_TYPE_APP_CALLBACK,
+                EventCallbackHelper.getCallbackType(callbackEvent)
+            );
         }
     }
 }
diff --git a/sdks/java-v2/templates/EventCallbackHelper.mustache b/sdks/java-v2/templates/EventCallbackHelper.mustache
index 6db22057d..d9e55681e 100644
--- a/sdks/java-v2/templates/EventCallbackHelper.mustache
+++ b/sdks/java-v2/templates/EventCallbackHelper.mustache
@@ -39,7 +39,11 @@ public class EventCallbackHelper {
     public static String getCallbackType(EventCallbackRequest eventCallback) {
         EventCallbackRequestEventMetadata metadata = eventCallback.getEvent().getEventMetadata();
 
-        if (metadata.getReportedForAppId() == null || metadata.getReportedForAppId().isEmpty()) {
+        if (
+            metadata == null ||
+            metadata.getReportedForAppId() == null ||
+            metadata.getReportedForAppId().isEmpty()
+        ) {
             return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
         }
 
diff --git a/sdks/node/dist/api.js b/sdks/node/dist/api.js
index 717890008..68eb52bb2 100644
--- a/sdks/node/dist/api.js
+++ b/sdks/node/dist/api.js
@@ -23653,7 +23653,7 @@ EventCallbackHelper.isValid = (apiKey, eventCallback) => {
   return eventCallback.event.eventHash === hmac.digest("hex").toString();
 };
 EventCallbackHelper.getCallbackType = (eventCallback) => {
-  if (!eventCallback.event.eventMetadata.reportedForAppId) {
+  if (!eventCallback.event.eventMetadata || !eventCallback.event.eventMetadata.reportedForAppId) {
     return _EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
   }
   return _EventCallbackHelper.EVENT_TYPE_APP_CALLBACK;
diff --git a/sdks/node/docs/model/EventCallbackRequestEvent.md b/sdks/node/docs/model/EventCallbackRequestEvent.md
index 385b38d51..e0f1dc87e 100644
--- a/sdks/node/docs/model/EventCallbackRequestEvent.md
+++ b/sdks/node/docs/model/EventCallbackRequestEvent.md
@@ -9,6 +9,6 @@ Name | Type | Description | Notes
 | `eventTime`<sup>*_required_</sup> | ```string``` |  Time the event was created (using Unix time).  |  |
 | `eventType`<sup>*_required_</sup> | ```string``` |  Type of callback event that was triggered.  |  |
 | `eventHash`<sup>*_required_</sup> | ```string``` |  Generated hash used to verify source of event data.  |  |
-| `eventMetadata`<sup>*_required_</sup> | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
+| `eventMetadata` | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
 
 [[Back to Model list]](../../README.md#models) [[Back to API list]](../../README.md#endpoints) [[Back to README]](../../README.md)
diff --git a/sdks/node/model/eventCallbackHelper.ts b/sdks/node/model/eventCallbackHelper.ts
index b26d1bb56..451ca3ed7 100644
--- a/sdks/node/model/eventCallbackHelper.ts
+++ b/sdks/node/model/eventCallbackHelper.ts
@@ -26,7 +26,10 @@ export class EventCallbackHelper {
    * "app_callback" will always include a value for "reported_for_app_id"
    */
   static getCallbackType = (eventCallback: EventCallbackRequest): string => {
-    if (!eventCallback.event.eventMetadata.reportedForAppId) {
+    if (
+      !eventCallback.event.eventMetadata ||
+      !eventCallback.event.eventMetadata.reportedForAppId
+    ) {
       return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
     }
 
diff --git a/sdks/node/model/eventCallbackRequestEvent.ts b/sdks/node/model/eventCallbackRequestEvent.ts
index 08f8dd28c..14d471035 100644
--- a/sdks/node/model/eventCallbackRequestEvent.ts
+++ b/sdks/node/model/eventCallbackRequestEvent.ts
@@ -41,7 +41,7 @@ export class EventCallbackRequestEvent {
    * Generated hash used to verify source of event data.
    */
   "eventHash": string;
-  "eventMetadata": EventCallbackRequestEventMetadata;
+  "eventMetadata"?: EventCallbackRequestEventMetadata;
 
   static discriminator: string | undefined = undefined;
 
diff --git a/sdks/node/templates/eventCallbackHelper.mustache b/sdks/node/templates/eventCallbackHelper.mustache
index dc541245d..d4bef7b26 100644
--- a/sdks/node/templates/eventCallbackHelper.mustache
+++ b/sdks/node/templates/eventCallbackHelper.mustache
@@ -24,7 +24,10 @@ export class EventCallbackHelper {
    * "app_callback" will always include a value for "reported_for_app_id"
    */
   static getCallbackType = (eventCallback: EventCallbackRequest): string => {
-    if (!eventCallback.event.eventMetadata.reportedForAppId) {
+    if (
+      !eventCallback.event.eventMetadata
+      || !eventCallback.event.eventMetadata.reportedForAppId
+    ) {
       return EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK;
     }
 
diff --git a/sdks/node/tests/model/eventCallbackHelper.test.ts b/sdks/node/tests/model/eventCallbackHelper.test.ts
index 1a9667cbd..019439c56 100644
--- a/sdks/node/tests/model/eventCallbackHelper.test.ts
+++ b/sdks/node/tests/model/eventCallbackHelper.test.ts
@@ -4,16 +4,30 @@ import { EventCallbackRequest, EventCallbackHelper } from '../../model';
 import { getFixtureData } from '../test_utils';
 
 describe('eventCallbackHelper', () => {
-  const fixtureData = getFixtureData('EventCallbackHelper');
   const apiKey = '324e3b0840f065eb51f3fd63231d0d33daa35d4ed10d27718839e81737065782';
   const apiKeyRev = apiKey.split('').reverse().join('');
 
-  for (const [key, data] of Object.entries(fixtureData)) {
-    it(`event callback for type ${key} is valid`, () => {
+  const account_keys = getFixtureData('EventCallbackHelper_AccountCallbacks');
+  for (const [key, data] of Object.entries(account_keys)) {
+    it(`account event callback for type ${key} is valid`, () => {
       const obj = EventCallbackRequest.init(data);
 
       expect(EventCallbackHelper.isValid(apiKey, obj)).toBeTruthy();
       expect(EventCallbackHelper.isValid(apiKeyRev, obj)).toBeFalsy();
+      expect(EventCallbackHelper.getCallbackType(obj))
+        .toEqual(EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK);
+    });
+  }
+
+  const app_keys = getFixtureData('EventCallbackHelper_AppCallbacks');
+  for (const [key, data] of Object.entries(app_keys)) {
+    it(`app event callback for type ${key} is valid`, () => {
+      const obj = EventCallbackRequest.init(data);
+
+      expect(EventCallbackHelper.isValid(apiKey, obj)).toBeTruthy();
+      expect(EventCallbackHelper.isValid(apiKeyRev, obj)).toBeFalsy();
+      expect(EventCallbackHelper.getCallbackType(obj))
+        .toEqual(EventCallbackHelper.EVENT_TYPE_APP_CALLBACK);
     });
   }
 });
diff --git a/sdks/node/types/model/eventCallbackRequestEvent.d.ts b/sdks/node/types/model/eventCallbackRequestEvent.d.ts
index 65db1d6aa..08f9888a3 100644
--- a/sdks/node/types/model/eventCallbackRequestEvent.d.ts
+++ b/sdks/node/types/model/eventCallbackRequestEvent.d.ts
@@ -4,7 +4,7 @@ export declare class EventCallbackRequestEvent {
     "eventTime": string;
     "eventType": EventCallbackRequestEvent.EventTypeEnum;
     "eventHash": string;
-    "eventMetadata": EventCallbackRequestEventMetadata;
+    "eventMetadata"?: EventCallbackRequestEventMetadata;
     static discriminator: string | undefined;
     static attributeTypeMap: AttributeTypeMap;
     static getAttributeTypeMap(): AttributeTypeMap;
diff --git a/sdks/php/docs/Model/EventCallbackRequestEvent.md b/sdks/php/docs/Model/EventCallbackRequestEvent.md
index 5fac892a7..84a3f872f 100644
--- a/sdks/php/docs/Model/EventCallbackRequestEvent.md
+++ b/sdks/php/docs/Model/EventCallbackRequestEvent.md
@@ -9,6 +9,6 @@ Name | Type | Description | Notes
 | `event_time`<sup>*_required_</sup> | ```string``` |  Time the event was created (using Unix time).  |  |
 | `event_type`<sup>*_required_</sup> | ```string``` |  Type of callback event that was triggered.  |  |
 | `event_hash`<sup>*_required_</sup> | ```string``` |  Generated hash used to verify source of event data.  |  |
-| `event_metadata`<sup>*_required_</sup> | [```\Dropbox\Sign\Model\EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
+| `event_metadata` | [```\Dropbox\Sign\Model\EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
 
 [[Back to Model list]](../../README.md#models) [[Back to API list]](../../README.md#endpoints) [[Back to README]](../../README.md)
diff --git a/sdks/php/src/EventCallbackHelper.php b/sdks/php/src/EventCallbackHelper.php
index 31a0fd856..094e770c4 100644
--- a/sdks/php/src/EventCallbackHelper.php
+++ b/sdks/php/src/EventCallbackHelper.php
@@ -70,8 +70,10 @@ public static function getCallbackType(
     ): string {
         $meta_data = $event_callback->getEvent()->getEventMetadata();
 
-        return !empty($meta_data->getReportedForAppId())
-            ? self::EVENT_TYPE_APP_CALLBACK
-            : self::EVENT_TYPE_ACCOUNT_CALLBACK;
+        if (empty($meta_data) || empty($meta_data->getReportedForAppId())) {
+            return self::EVENT_TYPE_ACCOUNT_CALLBACK;
+        }
+
+        return self::EVENT_TYPE_APP_CALLBACK;
     }
 }
diff --git a/sdks/php/src/Model/EventCallbackRequestEvent.php b/sdks/php/src/Model/EventCallbackRequestEvent.php
index ceddff811..7b106ffaf 100644
--- a/sdks/php/src/Model/EventCallbackRequestEvent.php
+++ b/sdks/php/src/Model/EventCallbackRequestEvent.php
@@ -302,9 +302,6 @@ public function listInvalidProperties()
         if ($this->container['event_hash'] === null) {
             $invalidProperties[] = "'event_hash' can't be null";
         }
-        if ($this->container['event_metadata'] === null) {
-            $invalidProperties[] = "'event_metadata' can't be null";
-        }
 
         return $invalidProperties;
     }
@@ -405,7 +402,7 @@ public function setEventHash(string $event_hash)
     /**
      * Gets event_metadata
      *
-     * @return EventCallbackRequestEventMetadata
+     * @return EventCallbackRequestEventMetadata|null
      */
     public function getEventMetadata()
     {
@@ -415,11 +412,11 @@ public function getEventMetadata()
     /**
      * Sets event_metadata
      *
-     * @param EventCallbackRequestEventMetadata $event_metadata event_metadata
+     * @param EventCallbackRequestEventMetadata|null $event_metadata event_metadata
      *
      * @return self
      */
-    public function setEventMetadata(EventCallbackRequestEventMetadata $event_metadata)
+    public function setEventMetadata(?EventCallbackRequestEventMetadata $event_metadata)
     {
         $this->container['event_metadata'] = $event_metadata;
 
diff --git a/sdks/php/templates/EventCallbackHelper.mustache b/sdks/php/templates/EventCallbackHelper.mustache
index 8f49a260f..7d887d339 100644
--- a/sdks/php/templates/EventCallbackHelper.mustache
+++ b/sdks/php/templates/EventCallbackHelper.mustache
@@ -65,8 +65,10 @@ abstract class EventCallbackHelper
     ): string {
         $meta_data = $event_callback->getEvent()->getEventMetadata();
 
-        return !empty($meta_data->getReportedForAppId())
-            ? self::EVENT_TYPE_APP_CALLBACK
-            : self::EVENT_TYPE_ACCOUNT_CALLBACK;
+        if (empty($meta_data) || empty($meta_data->getReportedForAppId())) {
+            return self::EVENT_TYPE_ACCOUNT_CALLBACK;
+        }
+
+        return self::EVENT_TYPE_APP_CALLBACK;
     }
 }
diff --git a/sdks/php/test/EventCallbackHelperTest.php b/sdks/php/test/EventCallbackHelperTest.php
index 0c9560b12..0580f0d48 100644
--- a/sdks/php/test/EventCallbackHelperTest.php
+++ b/sdks/php/test/EventCallbackHelperTest.php
@@ -17,33 +17,55 @@ class EventCallbackHelperTest extends SignTestCase
     public function testIsValid(
         string $apiKey,
         array $data,
-        bool $passes
+        bool $passes,
+        string $callback_type
     ) {
         $callback_event = EventCallbackRequest::init($data);
 
-        $isValid = EventCallbackHelper::isValid($apiKey, $callback_event);
+        $this->assertEquals(
+            $passes,
+            EventCallbackHelper::isValid($apiKey, $callback_event)
+        );
 
-        if ($passes) {
-            $this->assertTrue($isValid);
-        } else {
-            $this->assertFalse($isValid);
-        }
+        $this->assertEquals(
+            $callback_type,
+            EventCallbackHelper::getCallbackType($callback_event)
+        );
     }
 
     public function providerIsValid(): iterable
     {
-        $fixtures = TestUtils::getFixtureData('EventCallbackHelper');
-        foreach ($fixtures as $data) {
+        $account_fixtures = TestUtils::getFixtureData('EventCallbackHelper_AccountCallbacks');
+        foreach ($account_fixtures as $data) {
+            yield [
+                'apiKey' => self::APIKEY,
+                'data' => $data,
+                'passes' => true,
+                'callback_type' => EventCallbackHelper::EVENT_TYPE_ACCOUNT_CALLBACK,
+            ];
+
+            yield [
+                'apiKey' => strrev(self::APIKEY),
+                'data' => $data,
+                'passes' => false,
+                'callback_type' => EventCallbackHelper::EVENT_TYPE_ACCOUNT_CALLBACK,
+            ];
+        }
+
+        $app_fixtures = TestUtils::getFixtureData('EventCallbackHelper_AppCallbacks');
+        foreach ($app_fixtures as $data) {
             yield [
                 'apiKey' => self::APIKEY,
                 'data' => $data,
                 'passes' => true,
+                'callback_type' => EventCallbackHelper::EVENT_TYPE_APP_CALLBACK,
             ];
 
             yield [
                 'apiKey' => strrev(self::APIKEY),
                 'data' => $data,
                 'passes' => false,
+                'callback_type' => EventCallbackHelper::EVENT_TYPE_APP_CALLBACK,
             ];
         }
     }
diff --git a/sdks/python/docs/EventCallbackRequestEvent.md b/sdks/python/docs/EventCallbackRequestEvent.md
index 4b17fa876..d658d01a1 100644
--- a/sdks/python/docs/EventCallbackRequestEvent.md
+++ b/sdks/python/docs/EventCallbackRequestEvent.md
@@ -9,7 +9,7 @@ Basic information about the event that occurred.
 | `event_time`<sup>*_required_</sup> | ```str``` |  Time the event was created (using Unix time).  |  |
 | `event_type`<sup>*_required_</sup> | ```str``` |  Type of callback event that was triggered.  |  |
 | `event_hash`<sup>*_required_</sup> | ```str``` |  Generated hash used to verify source of event data.  |  |
-| `event_metadata`<sup>*_required_</sup> | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
+| `event_metadata` | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
diff --git a/sdks/python/dropbox_sign/event_callback_helper.py b/sdks/python/dropbox_sign/event_callback_helper.py
index b996774c0..e8a87d7d7 100644
--- a/sdks/python/dropbox_sign/event_callback_helper.py
+++ b/sdks/python/dropbox_sign/event_callback_helper.py
@@ -34,7 +34,7 @@ def get_callback_type(cls, event_callback: EventCallbackRequest):
         """
         metadata: EventCallbackRequestEventMetadata = event_callback.event.event_metadata
 
-        if not metadata.reported_for_app_id:
+        if not metadata or not metadata.reported_for_app_id:
             return cls.EVENT_TYPE_ACCOUNT_CALLBACK
 
         return cls.EVENT_TYPE_APP_CALLBACK
diff --git a/sdks/python/dropbox_sign/model/event_callback_request_event.py b/sdks/python/dropbox_sign/model/event_callback_request_event.py
index c70c2f669..c4b8d6ae1 100644
--- a/sdks/python/dropbox_sign/model/event_callback_request_event.py
+++ b/sdks/python/dropbox_sign/model/event_callback_request_event.py
@@ -190,14 +190,13 @@ def event_metadata(self, value: EventCallbackRequestEventMetadata):
 
     @classmethod
     @convert_js_args_to_python_args
-    def _from_openapi_data(cls, event_time, event_type, event_hash, event_metadata, *args, **kwargs):  # noqa: E501
+    def _from_openapi_data(cls, event_time, event_type, event_hash, *args, **kwargs):  # noqa: E501
         """EventCallbackRequestEvent - a model defined in OpenAPI
 
         Args:
             event_time (str): Time the event was created (using Unix time).
             event_type (str): Type of callback event that was triggered.
             event_hash (str): Generated hash used to verify source of event data.
-            event_metadata (EventCallbackRequestEventMetadata):
 
         Keyword Args:
             _check_type (bool): if True, values for parameters in openapi_types
@@ -230,6 +229,7 @@ def _from_openapi_data(cls, event_time, event_type, event_hash, event_metadata,
                                 Animal class but this time we won't travel
                                 through its discriminator because we passed in
                                 _visited_composed_classes = (Animal,)
+            event_metadata (EventCallbackRequestEventMetadata): [optional]  # noqa: E501
         """
 
         _check_type = kwargs.pop('_check_type', True)
@@ -260,7 +260,6 @@ def _from_openapi_data(cls, event_time, event_type, event_hash, event_metadata,
         self.event_time = event_time
         self.event_type = event_type
         self.event_hash = event_hash
-        self.event_metadata = event_metadata
         for var_name, var_value in kwargs.items():
             if var_name not in self.attribute_map and \
                         self._configuration is not None and \
@@ -281,14 +280,13 @@ def _from_openapi_data(cls, event_time, event_type, event_hash, event_metadata,
     ])
 
     @convert_js_args_to_python_args
-    def __init__(self, event_time, event_type, event_hash, event_metadata, *args, **kwargs):  # noqa: E501
+    def __init__(self, event_time, event_type, event_hash, *args, **kwargs):  # noqa: E501
         """EventCallbackRequestEvent - a model defined in OpenAPI
 
         Args:
             event_time (str): Time the event was created (using Unix time).
             event_type (str): Type of callback event that was triggered.
             event_hash (str): Generated hash used to verify source of event data.
-            event_metadata (EventCallbackRequestEventMetadata):
 
         Keyword Args:
             _check_type (bool): if True, values for parameters in openapi_types
@@ -321,6 +319,7 @@ def __init__(self, event_time, event_type, event_hash, event_metadata, *args, **
                                 Animal class but this time we won't travel
                                 through its discriminator because we passed in
                                 _visited_composed_classes = (Animal,)
+            event_metadata (EventCallbackRequestEventMetadata): [optional]  # noqa: E501
         """
 
         _check_type = kwargs.pop('_check_type', True)
@@ -349,7 +348,6 @@ def __init__(self, event_time, event_type, event_hash, event_metadata, *args, **
         self.event_time = event_time
         self.event_type = event_type
         self.event_hash = event_hash
-        self.event_metadata = event_metadata
         for var_name, var_value in kwargs.items():
             if var_name not in self.attribute_map and \
                         self._configuration is not None and \
diff --git a/sdks/python/templates/event_callback_helper.mustache b/sdks/python/templates/event_callback_helper.mustache
index b996774c0..e8a87d7d7 100644
--- a/sdks/python/templates/event_callback_helper.mustache
+++ b/sdks/python/templates/event_callback_helper.mustache
@@ -34,7 +34,7 @@ class EventCallbackHelper:
         """
         metadata: EventCallbackRequestEventMetadata = event_callback.event.event_metadata
 
-        if not metadata.reported_for_app_id:
+        if not metadata or not metadata.reported_for_app_id:
             return cls.EVENT_TYPE_ACCOUNT_CALLBACK
 
         return cls.EVENT_TYPE_APP_CALLBACK
diff --git a/sdks/python/tests/test_event_callback_helper.py b/sdks/python/tests/test_event_callback_helper.py
index ee5c15692..8ff764d65 100644
--- a/sdks/python/tests/test_event_callback_helper.py
+++ b/sdks/python/tests/test_event_callback_helper.py
@@ -8,16 +8,32 @@
 
 class TestEventCallbackHelper(unittest.TestCase):
     def test_is_valid(self):
-        fixture_data = get_fixture_data('EventCallbackHelper')
-
         api_key = '324e3b0840f065eb51f3fd63231d0d33daa35d4ed10d27718839e81737065782'
         api_key_rev = api_key[::-1]
 
-        for key, value in fixture_data.items():
+        account_data = get_fixture_data('EventCallbackHelper_AccountCallbacks')
+
+        for key, value in account_data.items():
+            obj = EventCallbackRequest.init(value)
+
+            self.assertTrue(EventCallbackHelper.is_valid(api_key, obj))
+            self.assertFalse(EventCallbackHelper.is_valid(api_key_rev, obj))
+            self.assertEqual(
+                EventCallbackHelper.EVENT_TYPE_ACCOUNT_CALLBACK,
+                EventCallbackHelper.get_callback_type(obj)
+            )
+
+        app_data = get_fixture_data('EventCallbackHelper_AppCallbacks')
+
+        for key, value in app_data.items():
             obj = EventCallbackRequest.init(value)
 
             self.assertTrue(EventCallbackHelper.is_valid(api_key, obj))
             self.assertFalse(EventCallbackHelper.is_valid(api_key_rev, obj))
+            self.assertEqual(
+                EventCallbackHelper.EVENT_TYPE_APP_CALLBACK,
+                EventCallbackHelper.get_callback_type(obj)
+            )
 
 
 if __name__ == '__main__':
diff --git a/sdks/ruby/docs/EventCallbackRequestEvent.md b/sdks/ruby/docs/EventCallbackRequestEvent.md
index 4a87f4ccb..3bcfb7b0c 100644
--- a/sdks/ruby/docs/EventCallbackRequestEvent.md
+++ b/sdks/ruby/docs/EventCallbackRequestEvent.md
@@ -9,5 +9,5 @@ Basic information about the event that occurred.
 | `event_time`<sup>*_required_</sup> | ```String``` |  Time the event was created (using Unix time).  |  |
 | `event_type`<sup>*_required_</sup> | ```String``` |  Type of callback event that was triggered.  |  |
 | `event_hash`<sup>*_required_</sup> | ```String``` |  Generated hash used to verify source of event data.  |  |
-| `event_metadata`<sup>*_required_</sup> | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
+| `event_metadata` | [```EventCallbackRequestEventMetadata```](EventCallbackRequestEventMetadata.md) |    |  |
 
diff --git a/sdks/ruby/lib/dropbox-sign/event_callback_helper.rb b/sdks/ruby/lib/dropbox-sign/event_callback_helper.rb
index 10094fcf2..eabea4cd1 100644
--- a/sdks/ruby/lib/dropbox-sign/event_callback_helper.rb
+++ b/sdks/ruby/lib/dropbox-sign/event_callback_helper.rb
@@ -44,7 +44,7 @@ def self.is_valid(api_key, event_callback)
     def self.get_callback_type(event_callback)
       metadata = event_callback.event.event_metadata || EventCallbackRequestEventMetadata.new
 
-      if metadata.reported_for_app_id.nil? || metadata.reported_for_app_id.empty?
+      if metadata.nil? || metadata.reported_for_app_id.nil? || metadata.reported_for_app_id.empty?
         return EVENT_TYPE_ACCOUNT_CALLBACK
       end
 
diff --git a/sdks/ruby/lib/dropbox-sign/models/event_callback_request_event.rb b/sdks/ruby/lib/dropbox-sign/models/event_callback_request_event.rb
index a5bb891e7..54659d60a 100644
--- a/sdks/ruby/lib/dropbox-sign/models/event_callback_request_event.rb
+++ b/sdks/ruby/lib/dropbox-sign/models/event_callback_request_event.rb
@@ -160,10 +160,6 @@ def list_invalid_properties
         invalid_properties.push('invalid value for "event_hash", event_hash cannot be nil.')
       end
 
-      if @event_metadata.nil?
-        invalid_properties.push('invalid value for "event_metadata", event_metadata cannot be nil.')
-      end
-
       invalid_properties
     end
 
@@ -175,7 +171,6 @@ def valid?
       event_type_validator = EnumAttributeValidator.new('String', ["account_confirmed", "unknown_error", "file_error", "sign_url_invalid", "signature_request_viewed", "signature_request_signed", "signature_request_sent", "signature_request_all_signed", "signature_request_email_bounce", "signature_request_remind", "signature_request_incomplete_qes", "signature_request_destroyed", "signature_request_canceled", "signature_request_downloadable", "signature_request_declined", "signature_request_reassigned", "signature_request_invalid", "signature_request_prepared", "signature_request_expired", "template_created", "template_error", "callback_test"])
       return false unless event_type_validator.valid?(@event_type)
       return false if @event_hash.nil?
-      return false if @event_metadata.nil?
       true
     end
 
diff --git a/sdks/ruby/spec/event_callback_helper_spec.rb b/sdks/ruby/spec/event_callback_helper_spec.rb
index 22ce9e66c..da9205490 100644
--- a/sdks/ruby/spec/event_callback_helper_spec.rb
+++ b/sdks/ruby/spec/event_callback_helper_spec.rb
@@ -6,16 +6,30 @@
 
 describe Dropbox::Sign::EventCallbackHelper do
   context 'EventCallbackHelper' do
-    fixture_data = get_fixture_data('EventCallbackHelper')
     api_key = '324e3b0840f065eb51f3fd63231d0d33daa35d4ed10d27718839e81737065782'
     api_key_rev = api_key.reverse
 
-    fixture_data.each do |key, data|
-      it "event callback for type #{key} is valid" do
+    account_data = get_fixture_data('EventCallbackHelper_AccountCallbacks')
+    account_data.each do |key, data|
+      it "account event callback for type #{key} is valid" do
         obj = Dropbox::Sign::EventCallbackRequest.init(data)
 
         expect(Dropbox::Sign::EventCallbackHelper.is_valid(api_key, obj)).to eq(true)
         expect(Dropbox::Sign::EventCallbackHelper.is_valid(api_key_rev, obj)).to eq(false)
+        expect(Dropbox::Sign::EventCallbackHelper.get_callback_type(obj))
+          .to eq(Dropbox::Sign::EventCallbackHelper::EVENT_TYPE_ACCOUNT_CALLBACK)
+      end
+    end
+
+    app_data = get_fixture_data('EventCallbackHelper_AppCallbacks')
+    app_data.each do |key, data|
+      it "app event callback for type #{key} is valid" do
+        obj = Dropbox::Sign::EventCallbackRequest.init(data)
+
+        expect(Dropbox::Sign::EventCallbackHelper.is_valid(api_key, obj)).to eq(true)
+        expect(Dropbox::Sign::EventCallbackHelper.is_valid(api_key_rev, obj)).to eq(false)
+        expect(Dropbox::Sign::EventCallbackHelper.get_callback_type(obj))
+          .to eq(Dropbox::Sign::EventCallbackHelper::EVENT_TYPE_APP_CALLBACK)
       end
     end
   end
diff --git a/sdks/ruby/templates/event_callback_helper.mustache b/sdks/ruby/templates/event_callback_helper.mustache
index 11979adcb..8dc45098a 100644
--- a/sdks/ruby/templates/event_callback_helper.mustache
+++ b/sdks/ruby/templates/event_callback_helper.mustache
@@ -36,7 +36,7 @@ module Dropbox::Sign
     def self.get_callback_type(event_callback)
       metadata = event_callback.event.event_metadata || EventCallbackRequestEventMetadata.new
 
-      if metadata.reported_for_app_id.nil? || metadata.reported_for_app_id.empty?
+      if metadata.nil? || metadata.reported_for_app_id.nil? || metadata.reported_for_app_id.empty?
         return EVENT_TYPE_ACCOUNT_CALLBACK
       end
 
diff --git a/test_fixtures/EventCallbackHelper_AccountCallbacks.json b/test_fixtures/EventCallbackHelper_AccountCallbacks.json
new file mode 100644
index 000000000..bbdf4186f
--- /dev/null
+++ b/test_fixtures/EventCallbackHelper_AccountCallbacks.json
@@ -0,0 +1,82 @@
+{
+  "base": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "unknown_error",
+      "event_hash": "c574f5d3090c2936360b4e36cf6835cf3e2206b84fdc6347e6b28ca721ae1371",
+      "event_metadata": {
+        "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+      }
+    }
+  },
+  "base_no_metadata": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "unknown_error",
+      "event_hash": "c574f5d3090c2936360b4e36cf6835cf3e2206b84fdc6347e6b28ca721ae1371"
+    }
+  },
+  "account": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "account_confirmed",
+      "event_hash": "6dc5b7aad93cf54915e0089d6c31d61b3833f66f51459171c69f8fa211308848",
+      "event_metadata": {
+        "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+      }
+    }
+  },
+  "account_no_metadata": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "account_confirmed",
+      "event_hash": "6dc5b7aad93cf54915e0089d6c31d61b3833f66f51459171c69f8fa211308848"
+    }
+  },
+  "signature_request": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "signature_request_sent",
+      "event_hash": "08d45a6b7677492b78be030cef18cfeaece8fe67e163cc8e526ee638ad483756",
+      "event_metadata": {
+        "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+      }
+    }
+  },
+  "signature_request_no_metadata": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "signature_request_sent",
+      "event_hash": "08d45a6b7677492b78be030cef18cfeaece8fe67e163cc8e526ee638ad483756"
+    }
+  },
+  "template": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "template_created",
+      "event_hash": "4a9b22fa68d5addb8b6313eea9d42ecb393903a4240b71503ef78e9dac6c100d",
+      "event_metadata": {
+        "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+      }
+    }
+  },
+  "template_no_metadata": {
+    "account_guid": "63522885f9261e2b04eea043933ee7313eb674fd",
+    "event": {
+      "event_time": "1348177752",
+      "event_type": "template_created",
+      "event_hash": "4a9b22fa68d5addb8b6313eea9d42ecb393903a4240b71503ef78e9dac6c100d"
+    }
+  }
+}
diff --git a/test_fixtures/EventCallbackHelper.json b/test_fixtures/EventCallbackHelper_AppCallbacks.json
similarity index 83%
rename from test_fixtures/EventCallbackHelper.json
rename to test_fixtures/EventCallbackHelper_AppCallbacks.json
index bfd23463d..bf6e9ad46 100644
--- a/test_fixtures/EventCallbackHelper.json
+++ b/test_fixtures/EventCallbackHelper_AppCallbacks.json
@@ -7,7 +7,8 @@
       "event_hash": "c574f5d3090c2936360b4e36cf6835cf3e2206b84fdc6347e6b28ca721ae1371",
       "event_metadata": {
         "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
-        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd",
+        "reported_for_app_id": "98891a1b59f312d04cd88e4e0c498d75e0ce0ce0"
       }
     }
   },
@@ -19,7 +20,8 @@
       "event_hash": "6dc5b7aad93cf54915e0089d6c31d61b3833f66f51459171c69f8fa211308848",
       "event_metadata": {
         "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
-        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd",
+        "reported_for_app_id": "98891a1b59f312d04cd88e4e0c498d75e0ce0ce0"
       }
     }
   },
@@ -31,7 +33,8 @@
       "event_hash": "08d45a6b7677492b78be030cef18cfeaece8fe67e163cc8e526ee638ad483756",
       "event_metadata": {
         "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
-        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd",
+        "reported_for_app_id": "98891a1b59f312d04cd88e4e0c498d75e0ce0ce0"
       }
     }
   },
@@ -43,7 +46,8 @@
       "event_hash": "4a9b22fa68d5addb8b6313eea9d42ecb393903a4240b71503ef78e9dac6c100d",
       "event_metadata": {
         "related_signature_id": "ad4d8a769b555fa5ef38691465d426682bf2c992",
-        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd"
+        "reported_for_account_id": "63522885f9261e2b04eea043933ee7313eb674fd",
+        "reported_for_app_id": "98891a1b59f312d04cd88e4e0c498d75e0ce0ce0"
       }
     }
   }