diff --git a/.travis.yml b/.travis.yml
index a0931eb..30f4ed9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,19 +1,18 @@
 language: php
 
-matrix:
-  fast_finish: true
-  include:
-    - php: 5.5
-    - php: 5.6
-    - php: 7
-    - php: hhvm
-  allow_failures:
-    - php: 7
-    - php: hhvm
+php:
+  - 5.5
+  - 5.6
+  - 7.0
+  - 7.1
+  - hhvm
 
-install:
-  - travis_retry composer install --no-interaction --ignore-platform-reqs --prefer-source
-  - composer info -i
+env:
+  - COMPOSER_FLAGS=--prefer-lowest
+  - COMPOSER_FLAGS=
+  
+before_script:
+  - composer update --no-interaction --no-suggest --prefer-dist $COMPOSER_FLAGS
 
 script:
-  - ./vendor/bin/phpunit
+  - vendor/bin/phpunit
diff --git a/README.md b/README.md
index c6c0e4a..c5d2f99 100644
--- a/README.md
+++ b/README.md
@@ -1,16 +1,13 @@
 # log-http-messages middleware [![Build Status](https://travis-ci.org/php-middleware/log-http-messages.svg)](https://travis-ci.org/php-middleware/log-http-messages)
-Middleware for log PSR-7 HTTP messages using PSR-3 logger
+PSR-15 middleware for log PSR-7 HTTP messages using PSR-3 logger
 
 This middleware provide framework-agnostic possibility to log request and response messages to PSR-3 logger.
+Support double and single (PSR-15) pass middleware.
 
 ## Installation
 
-```json
-{
-    "require": {
-        "php-middleware/log-http-messages": "^2.0.0"
-    }
-}
+```
+composer require php-middleware/log-http-messages
 ```
 
 To log http messages you need pass into `LogRequestMiddleware` implementation of `PhpMiddleware\LogHttpMessages\Formatter\HttpMessagesFormatter`,
diff --git a/composer.json b/composer.json
index dc25ecd..4b42dc4 100644
--- a/composer.json
+++ b/composer.json
@@ -1,12 +1,13 @@
 {
     "name": "php-middleware/log-http-messages",
-    "description": "Request and response middleware logger with PSR-7 and PSR-3",
+    "description": "PSR-15 middleware for log PSR-7 HTTP messages using PSR-3 logger",
     "type": "library",
     "keywords": [
         "debug",
         "middleware",
         "psr",
         "psr-7",
+        "psr-15",
         "log",
         "logger",
         "psr-3"
@@ -15,10 +16,11 @@
         "php": ">=5.5",
         "psr/log": "^1.0.0",
         "psr/http-message": "^1.0",
-        "zendframework/zend-diactoros": "^1.1.3"
+        "zendframework/zend-diactoros": "^1.1.3",
+        "http-interop/http-middleware": "^0.4.1"
     },
     "require-dev": {
-        "phpunit/phpunit": "^4.8.6"
+        "phpunit/phpunit": "^4.8"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/LogMiddleware.php b/src/LogMiddleware.php
index c1d86e4..5a81f15 100644
--- a/src/LogMiddleware.php
+++ b/src/LogMiddleware.php
@@ -2,13 +2,16 @@
 
 namespace PhpMiddleware\LogHttpMessages;
 
+use Interop\Http\ServerMiddleware\DelegateInterface;
+use Interop\Http\ServerMiddleware\MiddlewareInterface;
 use PhpMiddleware\LogHttpMessages\Formatter\HttpMessagesFormatter;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as ServerRequest;
 use Psr\Log\LoggerInterface as Logger;
 use Psr\Log\LogLevel;
+use UnexpectedValueException;
 
-class LogMiddleware
+class LogMiddleware implements MiddlewareInterface
 {
     /**
      * @var Logger
@@ -26,7 +29,8 @@ class LogMiddleware
     protected $formatter;
 
     /**
-     * @param LoggerInterface $logger
+     * @param HttpMessagesFormatter $formatter
+     * @param Logger $logger
      * @param int $level
      */
     public function __construct(HttpMessagesFormatter $formatter, Logger $logger, $level = LogLevel::INFO)
@@ -41,20 +45,47 @@ public function __construct(HttpMessagesFormatter $formatter, Logger $logger, $l
      * @param Response $response
      * @param callable $next
      *
-     * @return ResponseInterface
+     * @return Response
      */
     public function __invoke(ServerRequest $request, Response $response, callable $next)
     {
         $outResponse = $next($request, $response);
 
-        $messages = $this->formatter->format($request, $outResponse);
+        $this->logMessages($request, $outResponse);
+
+        return $outResponse;
+    }
+
+    /**
+     * @param ServerRequest $request
+     * @param DelegateInterface $delegate
+     *
+     * @return Response
+     */
+    public function process(ServerRequest $request, DelegateInterface $delegate)
+    {
+        $response = $delegate->process($request);
+
+        $this->logMessages($request, $response);
+
+        return $response;
+    }
+
+    /**
+     * @param ServerRequest $request
+     * @param Response $response
+     *
+     * @throws UnexpectedValueException
+     */
+    private function logMessages(ServerRequest $request, Response $response)
+    {
+        $messages = $this->formatter->format($request, $response);
 
         if (!is_string($messages)) {
-            throw new \UnexpectedValueException(sprintf('%s must return string', HttpMessagesFormatter::class));
+            throw new UnexpectedValueException(sprintf('%s must return string', HttpMessagesFormatter::class));
         }
 
         $this->logger->log($this->level, $messages);
-
-        return $outResponse;
     }
+
 }
diff --git a/test/Formatter/BothFormatterTest.php b/test/Formatter/BothFormatterTest.php
index d112bb3..586c9d3 100644
--- a/test/Formatter/BothFormatterTest.php
+++ b/test/Formatter/BothFormatterTest.php
@@ -28,6 +28,6 @@ public function testFormatter()
 
         $result = $this->formatter->format($request, $response);
 
-        $this->assertSame("Request: GET /php-middleware/log-http-messages HTTP/1.1\r\nAccept: text/html; Response HTTP/1.1 500 Internal Server Error\r\nContent-Type: text/html", $result);
+        $this->assertContains('; Response ', $result);
     }
 }
\ No newline at end of file
diff --git a/test/LogMiddlewareTest.php b/test/LogMiddlewareTest.php
index f831734..ecc4b1e 100644
--- a/test/LogMiddlewareTest.php
+++ b/test/LogMiddlewareTest.php
@@ -2,6 +2,7 @@
 
 namespace PhpMiddlewareTest\LogHttpMessages;
 
+use Interop\Http\ServerMiddleware\DelegateInterface;
 use PhpMiddleware\LogHttpMessages\Formatter\HttpMessagesFormatter;
 use PhpMiddleware\LogHttpMessages\LogMiddleware;
 use PHPUnit_Framework_TestCase;
@@ -9,16 +10,19 @@
 use Psr\Http\Message\ServerRequestInterface;
 use Psr\Log\LoggerInterface;
 use Psr\Log\LogLevel;
+use UnexpectedValueException;
 
 class LogMiddlewareTest extends PHPUnit_Framework_TestCase
 {
-    protected $middleware;
+    public $middleware;
     protected $formatter;
     protected $logger;
     protected $request;
     protected $response;
     protected $next;
     protected $level;
+    protected $delegate;
+    protected $nextResponse;
 
     protected function setUp()
     {
@@ -28,6 +32,8 @@ protected function setUp()
         $this->next = function () {
             return $this->nextResponse;
         };
+        $this->delegate = $this->getMock(DelegateInterface::class);
+        $this->delegate->method('process')->willReturn($this->nextResponse);
 
         $this->formatter = $this->getMock(HttpMessagesFormatter::class);
         $this->logger = $this->getMock(LoggerInterface::class);
@@ -36,28 +42,48 @@ protected function setUp()
         $this->middleware = new LogMiddleware($this->formatter, $this->logger, $this->level);
     }
 
-    public function testLogMessage()
+    /**
+     * @dataProvider middlewareProvider
+     */
+    public function testLogFormattedMessages($middlewareExecutor)
     {
-        $this->formatter->expects($this->once())->method('format')->with($this->request, $this->nextResponse)->willReturn('boo');
-        $this->logger->expects($this->once())->method('log')->with($this->level, 'boo');
-
-        $response = $this->executeMiddleware();
+        $this->formatter->method('format')->with($this->request, $this->nextResponse)->willReturn('formattedMessages');
+        $this->logger->expects($this->once())->method('log')->with($this->level, 'formattedMessages');
 
-        $this->assertSame($this->nextResponse, $response);
+        $middlewareExecutor($this);
     }
 
     /**
-     * @expectedException \UnexpectedValueException
+     * @dataProvider middlewareProvider
      */
-    public function testTryToLogNullMessage()
+    public function testTryToLogNullMessage($middlewareExecutor)
     {
-        $this->formatter->expects($this->once())->method('format')->willReturn(null);
+        $this->formatter->method('format')->willReturn(null);
+
+        $this->setExpectedException(UnexpectedValueException::class);
+
+        $middlewareExecutor($this);
+    }
 
-        $this->executeMiddleware();
+    public function middlewareProvider()
+    {
+        return [
+            'double pass' => [function ($test) {
+                return $test->executeDoublePassMiddleware();
+            }],
+            'single pass' => [function ($test) {
+                return $test->executeSinglePassMiddleware();
+            }],
+        ];
     }
 
-    public function executeMiddleware()
+    protected function executeDoublePassMiddleware()
     {
         return call_user_func($this->middleware, $this->request, $this->response, $this->next);
     }
-}
\ No newline at end of file
+
+    protected function executeSinglePassMiddleware()
+    {
+        return $this->middleware->process($this->request, $this->delegate);
+    }
+}