diff --git a/Makefile b/Makefile
index 30ded37cb..ceacdb242 100644
--- a/Makefile
+++ b/Makefile
@@ -53,4 +53,7 @@ demo:
 layers.json:
 	php runtime/layers/layer-list.php
 
-.PHONY: runtimes website website-preview website-assets demo layers.json
+test-stack:
+	serverless deploy -c tests/serverless.tests.yml
+
+.PHONY: runtimes website website-preview website-assets demo layers.json test-stack
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 5c2002910..3de6368c7 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -12,6 +12,7 @@ parameters:
     - %rootDir%/../../../tests/Bridge/Symfony/logs/*
     - %rootDir%/../../../tests/Sam/Php/*
     - %rootDir%/../../../tests/Sam/PhpFpm/*
+    - %rootDir%/../../../tests/Functional/fpm/*
 
   ignoreErrors:
     -
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 9070f9bc1..deb5c82a4 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -5,9 +5,11 @@
     <testsuites>
         <testsuite name="small">
             <directory>./tests/</directory>
+            <exclude>./tests/Functional</exclude>
             <exclude>./tests/Sam</exclude>
         </testsuite>
         <testsuite name="runtimes">
+            <directory>./tests/Functional</directory>
             <directory>./tests/Sam</directory>
         </testsuite>
     </testsuites>
diff --git a/runtime/layers/fpm/php.ini b/runtime/layers/fpm/php.ini
index ce677ea17..a3856b6c0 100644
--- a/runtime/layers/fpm/php.ini
+++ b/runtime/layers/fpm/php.ini
@@ -34,3 +34,8 @@ variables_order="EGPCS"
 ; The lambda environment is not compatible with fastcgi_finish_request
 ; See https://github.com/brefphp/bref/issues/214
 disable_functions=fastcgi_finish_request
+
+; The total upload size limit is 6Mb, we override the defaults to match this limit
+; API Gateway has a 10Mb limit, but Lambda's is 6Mb
+post_max_size=6M
+upload_max_filesize=6M
diff --git a/runtime/layers/web/default.conf b/runtime/layers/web/default.conf
index d4bc737f5..b1a9bad95 100644
--- a/runtime/layers/web/default.conf
+++ b/runtime/layers/web/default.conf
@@ -2,6 +2,8 @@ server {
     server_name php-docker.local;
     root /var/task/##DOCUMENT_ROOT##;
 
+    client_max_body_size 6M;
+
     location / {
         # try to serve file directly, fallback to handler
         try_files $uri /##HANDLER_DR##$is_args$args;
diff --git a/tests/Functional/FpmRuntimeTest.php b/tests/Functional/FpmRuntimeTest.php
new file mode 100644
index 000000000..0776cb9ef
--- /dev/null
+++ b/tests/Functional/FpmRuntimeTest.php
@@ -0,0 +1,244 @@
+<?php declare(strict_types=1);
+
+namespace Bref\Test\Functional;
+
+use GuzzleHttp\Client;
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\ResponseInterface;
+
+class FpmRuntimeTest extends TestCase
+{
+    /** @var Client */
+    private $http;
+
+    public function setUp(): void
+    {
+        parent::setUp();
+
+        $this->http = new Client([
+            'base_uri' => 'https://5octfcz6gc.execute-api.eu-west-1.amazonaws.com/dev/',
+            'http_errors' => false,
+        ]);
+    }
+
+    public function test GET()
+    {
+        $response = $this->http->request('GET');
+
+        $this->assertResponseSuccessful($response);
+        self::assertEquals('Hello world!', $this->getBody($response));
+    }
+
+    public function test GET with query parameter()
+    {
+        $response = $this->http->request('GET', '?name=Abby');
+
+        $this->assertResponseSuccessful($response);
+        self::assertEquals('Hello Abby', $this->getBody($response));
+    }
+
+    public function test stderr do not show in the HTTP response()
+    {
+        $response = $this->http->request('GET', '?stderr=1');
+
+        $this->assertResponseSuccessful($response);
+        self::assertNotContains('This is a test log into stderr', $this->responseAsString($response));
+    }
+
+    public function test error_log function()
+    {
+        $response = $this->http->request('GET', '?error_log=1');
+
+        $this->assertResponseSuccessful($response);
+        self::assertNotContains('This is a test log from error_log', $this->responseAsString($response));
+    }
+
+    public function test uncaught exception returns a 500 without the details()
+    {
+        $response = $this->http->request('GET', '?exception=1');
+
+        self::assertSame(500, $response->getStatusCode());
+        self::assertNotContains('This is an uncaught exception', $this->responseAsString($response));
+    }
+
+    public function test error returns a 500 without the details()
+    {
+        $response = $this->http->request('GET', '?error=1');
+
+        self::assertSame(500, $response->getStatusCode());
+        self::assertNotContains('strlen() expects exactly 1 parameter, 0 given', $this->responseAsString($response));
+    }
+
+    public function test fatal error returns a 500 without the details()
+    {
+        $response = $this->http->request('GET', '?fatal_error=1');
+
+        self::assertSame(500, $response->getStatusCode());
+        self::assertNotContains("require(): Failed opening required 'foo'", $this->responseAsString($response));
+    }
+
+    public function test warnings do not fail the request and do not appear in the response()
+    {
+        $response = $this->http->request('GET', '?warning=1');
+
+        $this->assertResponseSuccessful($response);
+        self::assertEquals('Hello world!', $this->getBody($response));
+        self::assertNotContains('This is a test warning', $this->responseAsString($response));
+    }
+
+    public function test php extensions()
+    {
+        $response = $this->http->request('GET', '?extensions=1');
+        $extensions = $this->getJsonBody($response);
+        sort($extensions);
+
+        self::assertEquals([
+            'Core',
+            'PDO',
+            'Phar',
+            'Reflection',
+            'SPL',
+            'SimpleXML',
+            'Zend OPcache',
+            'bcmath',
+            'cgi-fcgi',
+            'ctype',
+            'curl',
+            'date',
+            'dom',
+            'exif',
+            'fileinfo',
+            'filter',
+            'ftp',
+            'gd',
+            'gettext',
+            'hash',
+            'iconv',
+            'json',
+            'libxml',
+            'mbstring',
+            'mysqli',
+            'mysqlnd',
+            'openssl',
+            'pcntl',
+            'pcre',
+            'pdo_sqlite',
+            'posix',
+            'readline',
+            'session',
+            'soap',
+            'sockets',
+            'sodium',
+            'sqlite3',
+            'standard',
+            'tokenizer',
+            'xml',
+            'xmlreader',
+            'xmlwriter',
+            'xsl',
+            'zip',
+            'zlib',
+        ], $extensions);
+    }
+
+    /**
+     * Check some PHP config values
+     */
+    public function test php config()
+    {
+        $response = $this->http->request('GET', '?php-config=1');
+
+        self::assertArraySubset([
+            // On PHP-FPM we don't want errors to be sent to stdout because that sends them to the HTTP response
+            'display_errors' => '0',
+            // This is sent to PHP-FPM, which sends them back to CloudWatch
+            'error_log' => null,
+            // This is the default production value
+            'error_reporting' => (string) (E_ALL & ~E_DEPRECATED & ~E_STRICT),
+            'extension_dir' => '/opt/bref/lib/php/extensions/no-debug-zts-20190902',
+            // Same limit as API Gateway
+            'max_execution_time' => '30',
+            'max_input_time' => '60',
+            // Use the max amount of memory possibly available, lambda will limit us
+            'memory_limit' => '3008M',
+            'opcache.enable' => '1',
+            'opcache.enable_cli' => '0',
+            // Since we have PHP-FPM we don't need the file cache here
+            'opcache.file_cache' => null,
+            'opcache.max_accelerated_files' => '10000',
+            'opcache.memory_consumption' => '128',
+            // This is to make sure that we don't strip comments from source code since it would break annotations
+            'opcache.save_comments' => '1',
+            // The code is readonly on lambdas so it never changes
+            'opcache.validate_timestamps' => '0',
+            'short_open_tag' => '',
+            'zend.assertions' => '-1',
+            'zend.enable_gc' => '1',
+            // Check POST configuration
+            'post_max_size' => '6M',
+            'upload_max_filesize' => '6M',
+        ], $this->getJsonBody($response), false);
+    }
+
+    public function test environment variables()
+    {
+        $response = $this->http->request('GET', '?env=1');
+
+        self::assertEquals([
+            '$_ENV' => 'bar',
+            '$_SERVER' => 'bar',
+            'getenv' => 'bar',
+        ], $this->getJsonBody($response));
+    }
+
+    public function test error on invalid URL()
+    {
+        $response = $this->http->request('GET', 'missing-handler');
+
+        self::assertSame(403, $response->getStatusCode());
+        self::assertEquals(['message' => 'Missing Authentication Token'], $this->getJsonBody($response));
+    }
+
+    /**
+     * The API Gateway limit is 10Mb, but Lambda is 6Mb.
+     *
+     * @see https://docs.aws.amazon.com/lambda/latest/dg/gettingstarted-limits.html
+     * We check with 4Mb because this works. 5Mb fails, maybe because the whole size of the event
+     * is larger (because of the whole JSON formatting plus headers?).
+     */
+    public function test max upload size is 6Mb()
+    {
+        $body4Mb = str_repeat(' ', 1024 * 1024 * 4);
+        $response = $this->http->request('POST', '', [
+            'body' => $body4Mb,
+        ]);
+        $this->assertResponseSuccessful($response);
+        self::assertEquals('Received 4Mb', $this->getBody($response));
+    }
+
+    private function assertResponseSuccessful(ResponseInterface $response): void
+    {
+        self::assertSame(200, $response->getStatusCode(), $this->getBody($response));
+    }
+
+    private function getBody(ResponseInterface $response): string
+    {
+        return $response->getBody()->__toString();
+    }
+
+    private function getJsonBody(ResponseInterface $response)
+    {
+        return json_decode($response->getBody()->getContents(), true);
+    }
+
+    private function responseAsString(ResponseInterface $response): string
+    {
+        $string = '';
+        foreach ($response->getHeaders() as $name => $values) {
+            $string .= $name . ': ' . implode(', ', $values) . "\n";
+        }
+        $string .= "\n" . $this->getBody($response) . "\n";
+
+        return $string;
+    }
+}
diff --git a/tests/Functional/fpm/index.php b/tests/Functional/fpm/index.php
new file mode 100644
index 000000000..bd3b0a5cd
--- /dev/null
+++ b/tests/Functional/fpm/index.php
@@ -0,0 +1,58 @@
+<?php declare(strict_types=1);
+
+if ($_GET['extensions'] ?? false) {
+    header('Content-Type: application/json');
+    echo json_encode(get_loaded_extensions(), JSON_PRETTY_PRINT);
+    return;
+}
+
+if ($_GET['php-config'] ?? false) {
+    header('Content-Type: application/json');
+    echo json_encode(ini_get_all(null, false), JSON_PRETTY_PRINT);
+    return;
+}
+
+if ($_GET['env'] ?? false) {
+    header('Content-Type: application/json');
+    echo json_encode([
+        '$_ENV' => $_ENV['FOO'] ?? null,
+        '$_SERVER' => $_SERVER['FOO'] ?? null,
+        'getenv' => getenv('FOO'),
+    ], JSON_PRETTY_PRINT);
+    return;
+}
+
+if ($_GET['stderr'] ?? false) {
+    $stderr = fopen('php://stderr', 'a');
+    fwrite($stderr, 'This is a test log into stderr');
+    fclose($stderr);
+}
+
+if ($_GET['error_log'] ?? false) {
+    error_log('This is a test log from error_log');
+}
+
+if ($_GET['exception'] ?? false) {
+    throw new Exception('This is an uncaught exception');
+}
+
+if ($_GET['error'] ?? false) {
+    strlen();
+}
+
+if ($_GET['fatal_error'] ?? false) {
+    require 'foo';
+}
+
+if ($_GET['warning'] ?? false) {
+    trigger_error('This is a test warning', E_USER_WARNING);
+}
+
+if ($_SERVER['REQUEST_METHOD'] === 'POST') {
+    $body = file_get_contents('php://input');
+    $bodySize = round(strlen($body) / 1024 / 1024);
+    echo "Received {$bodySize}Mb";
+    return;
+}
+
+echo 'Hello ' . ($_GET['name'] ?? 'world!');
diff --git a/tests/Sam/PhpFpmRuntimeTest.php b/tests/Sam/PhpFpmRuntimeTest.php
index 52b30dadf..183bfcefe 100644
--- a/tests/Sam/PhpFpmRuntimeTest.php
+++ b/tests/Sam/PhpFpmRuntimeTest.php
@@ -7,6 +7,11 @@
 use Psr\Http\Message\ResponseInterface;
 use Symfony\Component\Process\Process;
 
+/**
+ * This test duplicates a little bit the FPM functional test.
+ *
+ * However, it is still useful to test logs (faster that downloading logs from live lambdas).
+ */
 class PhpFpmRuntimeTest extends TestCase
 {
     /** @var string */
@@ -18,22 +23,6 @@ public function setUp()
         $this->logs = '';
     }
 
-    public function test invocation without event()
-    {
-        $response = $this->invoke('/');
-
-        $this->assertResponseSuccessful($response);
-        self::assertEquals('Hello world!', $this->getBody($response), $this->logs);
-    }
-
-    public function test invocation with event()
-    {
-        $response = $this->invoke('/?name=Abby');
-
-        $this->assertResponseSuccessful($response);
-        self::assertEquals('Hello Abby', $this->getBody($response), $this->logs);
-    }
-
     public function test stderr ends up in logs()
     {
         $response = $this->invoke('/?stderr=1');
@@ -90,107 +79,6 @@ public function test warnings are logged()
         self::assertContains('Warning:  This is a test warning in /var/task/tests/Sam', $this->logs);
     }
 
-    public function test php extensions()
-    {
-        $response = $this->invoke('/?extensions=1');
-        $extensions = $this->getJsonBody($response);
-        sort($extensions);
-
-        self::assertEquals([
-            'Core',
-            'PDO',
-            'Phar',
-            'Reflection',
-            'SPL',
-            'SimpleXML',
-            'Zend OPcache',
-            'bcmath',
-            'cgi-fcgi',
-            'ctype',
-            'curl',
-            'date',
-            'dom',
-            'exif',
-            'fileinfo',
-            'filter',
-            'ftp',
-            'gd',
-            'gettext',
-            'hash',
-            'iconv',
-            'json',
-            'libxml',
-            'mbstring',
-            'mysqli',
-            'mysqlnd',
-            'openssl',
-            'pcntl',
-            'pcre',
-            'pdo_sqlite',
-            'posix',
-            'readline',
-            'session',
-            'soap',
-            'sockets',
-            'sodium',
-            'sqlite3',
-            'standard',
-            'tokenizer',
-            'xml',
-            'xmlreader',
-            'xmlwriter',
-            'xsl',
-            'zip',
-            'zlib',
-        ], $extensions, $this->logs);
-    }
-
-    /**
-     * Check some PHP config values
-     */
-    public function test php config()
-    {
-        $response = $this->invoke('/?php-config=1');
-
-        self::assertArraySubset([
-            // On PHP-FPM we don't want errors to be sent to stdout because that sends them to the HTTP response
-            'display_errors' => '0',
-            // This is sent to PHP-FPM, which sends them back to CloudWatch
-            'error_log' => null,
-            // This is the default production value
-            'error_reporting' => (string) (E_ALL & ~E_DEPRECATED & ~E_STRICT),
-            'extension_dir' => '/opt/bref/lib/php/extensions/no-debug-zts-20190902',
-            // Same limit as API Gateway
-            'max_execution_time' => '30',
-            // Use the max amount of memory possibly available, lambda will limit us
-            'memory_limit' => '3008M',
-            'opcache.enable' => '1',
-            'opcache.enable_cli' => '0',
-            // Since we have PHP-FPM we don't need the file cache here
-            'opcache.file_cache' => null,
-            'opcache.max_accelerated_files' => '10000',
-            'opcache.memory_consumption' => '128',
-            // This is to make sure that we don't strip comments from source code since it would break annotations
-            'opcache.save_comments' => '1',
-            // The code is readonly on lambdas so it never changes
-            'opcache.validate_timestamps' => '0',
-            'short_open_tag' => '',
-            'zend.assertions' => '-1',
-            'zend.enable_gc' => '1',
-        ], $this->getJsonBody($response), false, $this->logs);
-    }
-
-    public function test environment variables()
-    {
-        $response = $this->invoke('/?env=1');
-
-        self::assertEquals([
-            '$_ENV' => 'bar',
-            '$_SERVER' => 'bar',
-            'getenv' => 'bar',
-        ], $this->getJsonBody($response), $this->logs);
-    }
-
     /**
      * Check some PHP config values
      */
diff --git a/tests/serverless.tests.yml b/tests/serverless.tests.yml
new file mode 100644
index 000000000..7ea5dd2b3
--- /dev/null
+++ b/tests/serverless.tests.yml
@@ -0,0 +1,35 @@
+service: bref-tests
+
+provider:
+    name: aws
+    runtime: provided
+    region: eu-west-1
+    profile: bref-tests
+    apiGateway:
+        binaryMediaTypes:
+            - '*/*'
+
+plugins:
+    - ./index.js
+
+package:
+    exclude:
+        - '**'
+    include:
+        - 'src/**'
+        - 'tests/**'
+        - 'vendor/**'
+
+functions:
+
+    fpm:
+        handler: tests/Functional/fpm/index.php
+        description: 'Bref FPM test'
+        timeout: 5 # in seconds (API Gateway has a timeout of 29 seconds)
+        reservedConcurrency: 2
+        layers:
+            - ${bref:layer.php-74-fpm}
+        events:
+            -   http: 'ANY /'
+        environment:
+            FOO: bar