diff --git a/src/MockeryTools/Http/Exchange/TestOnlyExpectedExchangeHandler.php b/src/MockeryTools/Http/Exchange/TestOnlyExpectedExchangeHandler.php
new file mode 100644
index 0000000..b24493b
--- /dev/null
+++ b/src/MockeryTools/Http/Exchange/TestOnlyExpectedExchangeHandler.php
@@ -0,0 +1,242 @@
+<?php declare(strict_types = 1);
+
+namespace BrandEmbassy\MockeryTools\Http\Exchange;
+
+use Exception;
+use GuzzleHttp\Exception\RequestException;
+use GuzzleHttp\Promise\FulfilledPromise;
+use GuzzleHttp\Promise\PromiseInterface;
+use GuzzleHttp\Promise\RejectedPromise;
+use GuzzleHttp\Psr7\MultipartStream;
+use Nette\Utils\Json;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\StreamInterface;
+use function assert;
+use function is_array;
+use function json_decode;
+use function json_last_error;
+use function ksort;
+use function parse_str;
+use function sprintf;
+use function str_replace;
+use const JSON_ERROR_NONE;
+
+/**
+ * @phpstan-import-type TRequestOptions from TestOnlyExpectedExchangeFactory
+ */
+class TestOnlyExpectedExchangeHandler
+{
+    /**
+     * @var TestOnlyExpectedExchange[]
+     */
+    private array $expectedExchanges = [];
+
+
+    public function __invoke(): callable
+    {
+        return fn(RequestInterface $actualRequest): PromiseInterface => $this->handleRequest($actualRequest);
+    }
+
+
+    private function handleRequest(RequestInterface $actualRequest): PromiseInterface
+    {
+        foreach ($this->expectedExchanges as $key => $expectedExchange) {
+            $areRequestsSame = $this->areRequestsSame(
+                $expectedExchange->getRequest(),
+                $actualRequest,
+            );
+
+            if ($areRequestsSame) {
+                unset($this->expectedExchanges[$key]);
+
+                if ($expectedExchange->getResponse()->getStatusCode() >= 400) {
+                    return $this->createRejectedPromise($expectedExchange);
+                }
+
+                return new FulfilledPromise($expectedExchange->getResponse());
+            }
+        }
+
+        throw new Exception(
+            sprintf(
+                'Unexpected request: %s %s %s %s',
+                $actualRequest->getUri(),
+                $actualRequest->getMethod(),
+                Json::encode($actualRequest->getHeaders()),
+                $actualRequest->getBody(),
+            ),
+        );
+    }
+
+
+    public function expectExchange(TestOnlyExpectedExchange $expectedExchange): void
+    {
+        $this->expectedExchanges[] = $expectedExchange;
+    }
+
+
+    public function hasExpectedExchanges(): bool
+    {
+        return $this->expectedExchanges !== [];
+    }
+
+
+    /**
+     * @return TestOnlyExpectedExchange[]
+     */
+    public function getExpectedExchanges(): array
+    {
+        return $this->expectedExchanges;
+    }
+
+
+    private function areRequestsHeadersSame(RequestInterface $expectedRequest, RequestInterface $actualRequest): bool
+    {
+        $actualRequestHeaders = $actualRequest->getHeaders();
+        $expectedRequestHeaders = $expectedRequest->getHeaders();
+
+        /**
+         * Content-Type is unset here because it's generated by Guzzle at run-time using random_bytes function.
+         * We are unable to create the expected request with the same value.
+         *
+         * @see GuzzleHttp\Psr7\MultipartStream contrustor.
+         */
+        if ($actualRequest->getBody() instanceof MultipartStream) {
+            unset($actualRequestHeaders['Content-Type']);
+            unset($expectedRequestHeaders['Content-Type']);
+        }
+
+        ksort($actualRequestHeaders);
+        ksort($expectedRequestHeaders);
+
+        return $actualRequestHeaders === $expectedRequestHeaders;
+    }
+
+
+    private function areRequestsSame(RequestInterface $expectedRequest, RequestInterface $actualRequest): bool
+    {
+        $areHeadersSame = $this->areRequestsHeadersSame(
+            $expectedRequest,
+            $actualRequest,
+        );
+
+        if (!$areHeadersSame) {
+            return false;
+        }
+
+        $areBodiesSame = $this->areRequestsBodiesSame(
+            $expectedRequest,
+            $actualRequest,
+        );
+
+        if (!$areBodiesSame) {
+            return false;
+        }
+
+        return $expectedRequest->getMethod() === $actualRequest->getMethod()
+            && (string)$expectedRequest->getUri() === (string)$actualRequest->getUri();
+    }
+
+
+    private function areRequestsBodiesSame(RequestInterface $expectedRequest, RequestInterface $actualRequest): bool
+    {
+        if ($actualRequest->getBody() instanceof MultipartStream
+            && $expectedRequest->getBody() instanceof MultipartStream) {
+            return $this->areRequestsMultipartStreamsSame($expectedRequest->getBody(), $actualRequest->getBody());
+        }
+
+        $expectedRequestBody = (string)$expectedRequest->getBody();
+        $actualRequestBody = (string)$actualRequest->getBody();
+
+        if ($actualRequest->getHeaderLine('Content-Type') === 'application/x-www-form-urlencoded') {
+            return $this->areRequestsFormsBodySame($expectedRequestBody, $actualRequestBody);
+        }
+
+        if ($this->isRequestBodyJson($actualRequestBody)
+            && $this->isRequestBodyJson($expectedRequestBody)
+        ) {
+            return $this->areRequestsJsonBodiesSame($expectedRequestBody, $actualRequestBody);
+        }
+
+        return $expectedRequestBody === $actualRequestBody;
+    }
+
+
+    private function areRequestsJsonBodiesSame(string $expectedRequestBody, string $actualRequestBody): bool
+    {
+        $expectedRequestBody = Json::decode($expectedRequestBody, Json::FORCE_ARRAY);
+        $actualRequestBody = Json::decode($actualRequestBody, Json::FORCE_ARRAY);
+
+        $expectedRequestBody = $this->sortRequestBody($expectedRequestBody);
+        $actualRequestBody = $this->sortRequestBody($actualRequestBody);
+
+        return $expectedRequestBody === $actualRequestBody;
+    }
+
+
+    private function areRequestsMultipartStreamsSame(StreamInterface $expectedRequestStream, StreamInterface $actualRequestStream): bool
+    {
+        assert($expectedRequestStream instanceof MultipartStream);
+        assert($actualRequestStream instanceof MultipartStream);
+
+        if ($expectedRequestStream->getSize() !== $actualRequestStream->getSize()) {
+            return false;
+        }
+
+        $expectedRequestContentWithoutBoundary = str_replace($expectedRequestStream->getBoundary(), '', $expectedRequestStream->getContents());
+        $actualRequestContentWithoutBoundary = str_replace($actualRequestStream->getBoundary(), '', $actualRequestStream->getContents());
+
+        return $expectedRequestContentWithoutBoundary === $actualRequestContentWithoutBoundary;
+    }
+
+
+    private function areRequestsFormsBodySame(string $expectedRequestBody, string $actualRequestBody): bool
+    {
+        $parsedExpectedRequestBody = [];
+        parse_str($expectedRequestBody, $parsedExpectedRequestBody);
+
+        $parsedActualRequestBody = [];
+        parse_str($actualRequestBody, $parsedActualRequestBody);
+
+        return $this->sortRequestBody($parsedExpectedRequestBody) === $this->sortRequestBody($parsedActualRequestBody);
+    }
+
+
+    /**
+     * @param mixed[] $requestBody
+     *
+     * @return mixed[]
+     */
+    private function sortRequestBody(array &$requestBody): array
+    {
+        ksort($requestBody);
+
+        foreach ($requestBody as &$value) {
+            if (is_array($value)) {
+                $this->sortRequestBody($value);
+            }
+        }
+        unset($value);
+
+        return $requestBody;
+    }
+
+
+    private function isRequestBodyJson(string $requestBody): bool
+    {
+        json_decode($requestBody);
+
+        return json_last_error() === JSON_ERROR_NONE;
+    }
+
+
+    private function createRejectedPromise(TestOnlyExpectedExchange $expectedExchange): RejectedPromise
+    {
+        $requestException = RequestException::create(
+            $expectedExchange->getRequest(),
+            $expectedExchange->getResponse(),
+        );
+
+        return new RejectedPromise($requestException);
+    }
+}