diff --git a/.gitignore b/.gitignore
index 8184b294..0d0f1747 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ vendor
 composer.lock
 .php_cs.cache
 .phpunit.result.cache
+*.har
diff --git a/composer.json b/composer.json
index e31e85bf..add287bf 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,7 @@
     ],
     "require": {
         "php": ">=7.2",
-        "amphp/amp": "^2.2",
+        "amphp/amp": "^2.4",
         "amphp/byte-stream": "^1.6",
         "amphp/hpack": "^2",
         "amphp/http": "^1.3",
diff --git a/examples/basic/1-get-request.php b/examples/basic/1-get-request.php
index ca6eadff..b860b6c8 100644
--- a/examples/basic/1-get-request.php
+++ b/examples/basic/1-get-request.php
@@ -29,7 +29,7 @@
         dumpResponseBodyPreview(yield $response->getBody()->buffer());
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/basic/2-custom-header.php b/examples/basic/2-custom-header.php
index 2460d0e2..888ff582 100644
--- a/examples/basic/2-custom-header.php
+++ b/examples/basic/2-custom-header.php
@@ -32,7 +32,7 @@
         dumpResponseBodyPreview(yield $response->getBody()->buffer());
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/basic/3-post-body.php b/examples/basic/3-post-body.php
index 1865d291..95091cbe 100644
--- a/examples/basic/3-post-body.php
+++ b/examples/basic/3-post-body.php
@@ -34,7 +34,7 @@
         dumpResponseBodyPreview(yield $response->getBody()->buffer());
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/basic/4-forms.php b/examples/basic/4-forms.php
index f3907987..3c568eeb 100644
--- a/examples/basic/4-forms.php
+++ b/examples/basic/4-forms.php
@@ -40,7 +40,7 @@
         dumpResponseBodyPreview(yield $response->getBody()->buffer());
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/basic/5-unix-sockets.php b/examples/basic/5-unix-sockets.php
index 7855f248..29984992 100644
--- a/examples/basic/5-unix-sockets.php
+++ b/examples/basic/5-unix-sockets.php
@@ -39,7 +39,7 @@
         dumpResponseBodyPreview(yield $response->getBody()->buffer());
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/basic/6-customization.php b/examples/basic/6-customization.php
index 8b623066..3a8506df 100644
--- a/examples/basic/6-customization.php
+++ b/examples/basic/6-customization.php
@@ -2,6 +2,7 @@
 
 use Amp\Http\Client\HttpClientBuilder;
 use Amp\Http\Client\HttpException;
+use Amp\Http\Client\Interceptor\LogIntoHttpArchive;
 use Amp\Http\Client\Interceptor\MatchOrigin;
 use Amp\Http\Client\Interceptor\SetRequestHeader;
 use Amp\Http\Client\Request;
@@ -13,21 +14,24 @@
 Loop::run(static function () use ($argv) {
     try {
         $client = (new HttpClientBuilder)
+            ->intercept(new LogIntoHttpArchive(__DIR__ . '/log.har'))
             ->intercept(new MatchOrigin(['https://amphp.org' => new SetRequestHeader('x-amphp', 'true')]))
             ->followRedirects(0)
             ->retry(3)
             ->build();
 
-        /** @var Response $response */
-        $response = yield $client->request(new Request($argv[1] ?? 'https://httpbin.org/user-agent'));
+        for ($i = 0; $i < 5; $i++) {
+            /** @var Response $response */
+            $response = yield $client->request(new Request($argv[1] ?? 'https://httpbin.org/user-agent'));
 
-        dumpRequestTrace($response->getRequest());
-        dumpResponseTrace($response);
+            dumpRequestTrace($response->getRequest());
+            dumpResponseTrace($response);
 
-        dumpResponseBodyPreview(yield $response->getBody()->buffer());
+            dumpResponseBodyPreview(yield $response->getBody()->buffer());
+        }
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/basic/7-gzip.php b/examples/basic/7-gzip.php
index 146a30fc..66d0fa4d 100644
--- a/examples/basic/7-gzip.php
+++ b/examples/basic/7-gzip.php
@@ -22,7 +22,7 @@
         dumpResponseBodyPreview(yield $response->getBody()->buffer());
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/concurrency/1-concurrent-fetch.php b/examples/concurrency/1-concurrent-fetch.php
index ff6f0b63..ffefb070 100644
--- a/examples/concurrency/1-concurrent-fetch.php
+++ b/examples/concurrency/1-concurrent-fetch.php
@@ -39,7 +39,7 @@
         }
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/examples/concurrency/3-benchmark.php b/examples/concurrency/3-benchmark.php
index 225fd4ff..8b89c4fa 100644
--- a/examples/concurrency/3-benchmark.php
+++ b/examples/concurrency/3-benchmark.php
@@ -13,7 +13,7 @@
 use Amp\Socket\ClientTlsContext;
 use Amp\Socket\ConnectContext;
 use function Amp\coroutine;
-use function Amp\Internal\getCurrentTime;
+use function Amp\getCurrentTime;
 
 require __DIR__ . '/../.helper/functions.php';
 
@@ -21,7 +21,7 @@
 
 Loop::run(static function () use ($count, $argv) {
     // Disable peer verification (not recommended, but we use a random test certificate here)
-    $tlsContext = (new ClientTlsContext)
+    $tlsContext = (new ClientTlsContext(''))
         ->withoutPeerVerification();
 
     $connectContext = (new ConnectContext)
@@ -33,7 +33,7 @@
 
     $handler = coroutine(static function (int $count) use ($client, $argv) {
         for ($i = 0; $i < $count; $i++) {
-            $request = new Request($argv[2] ?? 'http://localhost:1337/');
+            $request = new Request($argv[2] ?? 'https://localhost:1338/');
             $request->setTcpConnectTimeout(1000);
             $request->setTlsHandshakeTimeout(1000);
             $request->setTransferTimeout(1000);
diff --git a/examples/streaming/1-large-response.php b/examples/streaming/1-large-response.php
index 498ad88b..b753eb2a 100644
--- a/examples/streaming/1-large-response.php
+++ b/examples/streaming/1-large-response.php
@@ -88,7 +88,7 @@ function formatBytes(int $size, int $precision = 2)
         print \sprintf("%s has a size of %.2fMB\r\n", $path, (float) $size / 1024 / 1024);
     } catch (HttpException $error) {
         // If something goes wrong Amp will throw the exception where the promise was yielded.
-        // The Client::request() method itself will never throw directly, but returns a promise.
+        // The HttpClient::request() method itself will never throw directly, but returns a promise.
         echo $error;
     }
 });
diff --git a/src/Connection/Http1Connection.php b/src/Connection/Http1Connection.php
index 8d20bec3..4dfbea91 100644
--- a/src/Connection/Http1Connection.php
+++ b/src/Connection/Http1Connection.php
@@ -12,6 +12,7 @@
 use Amp\Emitter;
 use Amp\Http;
 use Amp\Http\Client\Connection\Internal\Http1Parser;
+use Amp\Http\Client\HarAttributes;
 use Amp\Http\Client\HttpException;
 use Amp\Http\Client\Internal\ForbidCloning;
 use Amp\Http\Client\Internal\ForbidSerialization;
@@ -35,6 +36,7 @@
 use Amp\TimeoutCancellationToken;
 use function Amp\asyncCall;
 use function Amp\call;
+use function Amp\getCurrentTime;
 
 /**
  * Socket client implementation.
@@ -188,7 +190,9 @@ private function request(Request $request, CancellationToken $cancellation): Pro
             $id = $combinedCancellation->subscribe([$this, 'close']);
 
             try {
+                $request->setAttribute(HarAttributes::TIME_SEND, getCurrentTime());
                 yield from $this->writeRequest($request, $protocolVersion, $combinedCancellation);
+                $request->setAttribute(HarAttributes::TIME_WAIT, getCurrentTime());
                 return yield from $this->readResponse($request, $cancellation, $combinedCancellation);
             } finally {
                 $combinedCancellation->unsubscribe($id);
@@ -252,8 +256,15 @@ private function readResponse(
 
         $parser = new Http1Parser($request, $bodyCallback, $trailersCallback);
 
+        $firstRead = true;
+
         try {
             while (null !== $chunk = yield $this->socket->read()) {
+                if ($firstRead) {
+                    $request->setAttribute(HarAttributes::TIME_RECEIVE, getCurrentTime());
+                    $firstRead = false;
+                }
+
                 $response = $parser->parse($chunk);
                 if ($response === null) {
                     continue;
@@ -326,6 +337,8 @@ private function readResponse(
 
                         $this->busy = false;
 
+                        $request->setAttribute(HarAttributes::TIME_COMPLETE, getCurrentTime());
+
                         $bodyEmitter->complete();
                         $trailersDeferred->resolve($trailers);
                     } catch (\Throwable $e) {
diff --git a/src/Connection/Http2Connection.php b/src/Connection/Http2Connection.php
index 72cb2b83..aebedcba 100644
--- a/src/Connection/Http2Connection.php
+++ b/src/Connection/Http2Connection.php
@@ -14,6 +14,7 @@
 use Amp\Emitter;
 use Amp\Failure;
 use Amp\Http\Client\Connection\Internal\Http2Stream;
+use Amp\Http\Client\HarAttributes;
 use Amp\Http\Client\HttpException;
 use Amp\Http\Client\Internal\ForbidCloning;
 use Amp\Http\Client\Internal\ForbidSerialization;
@@ -35,6 +36,7 @@
 use League\Uri;
 use function Amp\asyncCall;
 use function Amp\call;
+use function Amp\getCurrentTime;
 
 final class Http2Connection implements Connection
 {
@@ -168,6 +170,15 @@ final class Http2Connection implements Connection
     /** @var Deferred|null */
     private $pongDeferred;
 
+    /** @var string|null */
+    private $idleWatcher;
+
+    /** @var int */
+    private $idlePings = 0;
+
+    /** @var int */
+    private $requestCount = 0;
+
     public function __construct(EncryptableSocket $socket)
     {
         $this->table = new HPack;
@@ -218,11 +229,7 @@ public function getStream(Request $request): Promise
             throw new \Error('The promise returned from ' . __CLASS__ . '::initialize() must resolve before using the connection');
         }
 
-        return call(function () use ($request) {
-            if ($this->streamId > 0 && empty($this->streams) && !yield $this->ping()) {
-                return null;
-            }
-
+        return call(function () {
             if ($this->remainingStreams <= 0 || $this->onClose === null) {
                 return null;
             }
@@ -237,28 +244,6 @@ public function getStream(Request $request): Promise
         });
     }
 
-    /**
-     * @return Promise<bool> Fulfilled with true if a pong is received within the timeout, false if none is received.
-     */
-    private function ping(): Promise
-    {
-        if ($this->onClose === null) {
-            return new Success(false);
-        }
-
-        if ($this->pongDeferred !== null) {
-            return $this->pongDeferred->promise();
-        }
-
-        $this->pongDeferred = new Deferred;
-
-        $this->writeFrame($this->counter++, self::PING, self::NOFLAG);
-
-        $this->pongWatcher = Loop::delay(self::PONG_TIMEOUT, [$this, 'close']);
-
-        return $this->pongDeferred->promise();
-    }
-
     public function onClose(callable $onClose): void
     {
         if ($this->onClose === null) {
@@ -289,8 +274,36 @@ public function getTlsInfo(): ?TlsInfo
         return $this->socket instanceof EncryptableSocket ? $this->socket->getTlsInfo() : null;
     }
 
+    /**
+     * @return Promise<bool> Fulfilled with true if a pong is received within the timeout, false if none is received.
+     */
+    private function ping(): Promise
+    {
+        if ($this->onClose === null) {
+            return new Success(false);
+        }
+
+        if ($this->pongDeferred !== null) {
+            return $this->pongDeferred->promise();
+        }
+
+        $this->pongDeferred = new Deferred;
+        $this->idlePings++;
+
+        $this->writeFrame($this->counter++, self::PING, self::NOFLAG);
+
+        $this->pongWatcher = Loop::delay(self::PONG_TIMEOUT, [$this, 'close']);
+
+        return $this->pongDeferred->promise();
+    }
+
     private function request(Request $request, CancellationToken $token): Promise
     {
+        $this->requestCount++;
+
+        $this->idlePings = 0;
+        $this->cancelIdleWatcher();
+
         // Remove defunct HTTP/1.x headers.
         $request->removeHeader('host');
         $request->removeHeader('connection');
@@ -374,6 +387,8 @@ private function request(Request $request, CancellationToken $token): Promise
                     ":method" => [$request->getMethod()],
                 ], $request->getHeaders());
 
+                $request->setAttribute(HarAttributes::TIME_SEND, getCurrentTime());
+
                 $headers = $this->table->encode($headers);
 
                 $stream = $body->createBodyStream();
@@ -381,6 +396,8 @@ private function request(Request $request, CancellationToken $token): Promise
                 $chunk = yield $stream->read();
 
                 if (!isset($this->streams[$id]) || $token->isRequested()) {
+                    $request->setAttribute(HarAttributes::TIME_WAIT, getCurrentTime());
+
                     return yield $deferred->promise();
                 }
 
@@ -401,12 +418,16 @@ private function request(Request $request, CancellationToken $token): Promise
                 }
 
                 if ($chunk === null) {
+                    $request->setAttribute(HarAttributes::TIME_WAIT, getCurrentTime());
+
                     return yield $deferred->promise();
                 }
 
                 $buffer = $chunk;
                 while (null !== $chunk = yield $stream->read()) {
                     if (!isset($this->streams[$id]) || $token->isRequested()) {
+                        $request->setAttribute(HarAttributes::TIME_WAIT, getCurrentTime());
+
                         return yield $deferred->promise();
                     }
 
@@ -415,6 +436,8 @@ private function request(Request $request, CancellationToken $token): Promise
                 }
 
                 if (!isset($this->streams[$id]) || $token->isRequested()) {
+                    $request->setAttribute(HarAttributes::TIME_WAIT, getCurrentTime());
+
                     return yield $deferred->promise();
                 }
 
@@ -422,11 +445,18 @@ private function request(Request $request, CancellationToken $token): Promise
 
                 yield $this->writeData($buffer, $id);
 
+                $request->setAttribute(HarAttributes::TIME_WAIT, getCurrentTime());
+
                 return yield $deferred->promise();
             } catch (\Throwable $exception) {
                 if (isset($this->streams[$id])) {
                     $this->releaseStream($id, $exception);
                 }
+
+                if ($exception instanceof StreamException) {
+                    $exception = new HttpException('Failed to write request: ' . $exception->getMessage());
+                }
+
                 throw $exception;
             } finally {
                 $token->unsubscribe($cancellationId);
@@ -750,6 +780,10 @@ private function parser(): \Generator
 
                             unset($this->bodyEmitters[$id], $this->trailerDeferreds[$id]);
 
+                            $stream->request->setAttribute(HarAttributes::TIME_COMPLETE, getCurrentTime());
+
+                            $this->setupPingIfIdle();
+
                             $emitter->complete();
                             $deferred->resolve(new Trailers([]));
 
@@ -1342,6 +1376,10 @@ private function parser(): \Generator
 
                             unset($this->bodyEmitters[$id], $this->trailerDeferreds[$id]);
 
+                            $stream->request->setAttribute(HarAttributes::TIME_COMPLETE, getCurrentTime());
+
+                            $this->setupPingIfIdle();
+
                             $emitter->complete();
                             $deferred->resolve($headers);
 
@@ -1374,6 +1412,8 @@ private function parser(): \Generator
                         $deferred = $this->pendingRequests[$id];
                         unset($this->pendingRequests[$id]);
 
+                        $stream->request->setAttribute(HarAttributes::TIME_RECEIVE, getCurrentTime());
+
                         if ($stream->state & Http2Stream::REMOTE_CLOSED) {
                             $response = new Response(
                                 '2',
@@ -1508,6 +1548,8 @@ private function shutdown(?int $lastId = null, ?\Throwable $reason = null): Prom
                 Loop::cancel($this->pongWatcher);
             }
 
+            $this->cancelIdleWatcher();
+
             if ($this->onClose !== null) {
                 $onClose = $this->onClose;
                 $this->onClose = null;
@@ -1600,4 +1642,50 @@ private function sendBufferedData(): void
             $this->writeBufferedData($id);
         }
     }
+
+    private function setupPingIfIdle(): void
+    {
+        if ($this->idleWatcher !== null) {
+            return;
+        }
+
+        $this->idleWatcher = Loop::defer(function ($watcher) {
+            \assert($this->idleWatcher === null || $this->idleWatcher === $watcher);
+
+            $this->idleWatcher = null;
+            if (!empty($this->streams)) {
+                return;
+            }
+
+            $this->idleWatcher = Loop::delay(60000, function ($watcher) {
+                \assert($this->idleWatcher === null || $this->idleWatcher === $watcher);
+                \assert(empty($this->streams));
+
+                $this->idleWatcher = null;
+
+                $maxIdleMinutes = $this->requestCount < 2 ? 1 : 3;
+
+                if ($this->idlePings + 1 >= $maxIdleMinutes) {
+                    $this->close();
+                    return;
+                }
+
+                if (yield $this->ping()) {
+                    $this->setupPingIfIdle();
+                }
+            });
+
+            Loop::unreference($this->idleWatcher);
+        });
+
+        Loop::unreference($this->idleWatcher);
+    }
+
+    private function cancelIdleWatcher(): void
+    {
+        if ($this->idleWatcher !== null) {
+            Loop::cancel($this->idleWatcher);
+            $this->idleWatcher = null;
+        }
+    }
 }
diff --git a/src/Connection/UnlimitedConnectionPool.php b/src/Connection/UnlimitedConnectionPool.php
index 5d42e400..cbf89aec 100644
--- a/src/Connection/UnlimitedConnectionPool.php
+++ b/src/Connection/UnlimitedConnectionPool.php
@@ -7,6 +7,7 @@
 use Amp\CancelledException;
 use Amp\CombinedCancellationToken;
 use Amp\Coroutine;
+use Amp\Http\Client\HarAttributes;
 use Amp\Http\Client\Internal\ForbidSerialization;
 use Amp\Http\Client\InvalidRequestException;
 use Amp\Http\Client\Request;
@@ -21,6 +22,7 @@
 use Amp\Success;
 use Amp\TimeoutCancellationToken;
 use function Amp\call;
+use function Amp\getCurrentTime;
 
 final class UnlimitedConnectionPool implements ConnectionPool
 {
@@ -144,9 +146,13 @@ public function getStream(Request $request, CancellationToken $cancellation): Pr
                     continue; // No stream available for the given request.
                 }
 
+                $request->setAttribute(HarAttributes::TIME_CONNECT, getCurrentTime());
+
                 return $stream;
             }
 
+            $request->setAttribute(HarAttributes::TIME_CONNECT, getCurrentTime());
+
             $promise = new Coroutine($this->createConnection($request, $cancellation, $authority, $isHttps));
 
             $hash = \spl_object_hash($promise);
@@ -244,6 +250,8 @@ private function createConnection(
         }
 
         try {
+            $request->setAttribute(HarAttributes::TIME_SSL, getCurrentTime());
+
             $tlsState = $socket->getTlsState();
             if ($tlsState === EncryptableSocket::TLS_STATE_DISABLED) {
                 $tlsCancellationToken = new CombinedCancellationToken(
diff --git a/src/HarAttributes.php b/src/HarAttributes.php
new file mode 100644
index 00000000..d925d9f7
--- /dev/null
+++ b/src/HarAttributes.php
@@ -0,0 +1,17 @@
+<?php
+
+namespace Amp\Http\Client;
+
+final class HarAttributes
+{
+    public const STARTED_DATE_TIME = 'amp.http.client.har.startedDateTime';
+    public const SERVER_IP_ADDRESS = 'amp.http.client.har.serverIPAddress';
+
+    public const TIME_START = 'amp.http.client.har.timings.start';
+    public const TIME_SSL = 'amp.http.client.har.timings.ssl';
+    public const TIME_CONNECT = 'amp.http.client.har.timings.connect';
+    public const TIME_SEND = 'amp.http.client.har.timings.send';
+    public const TIME_WAIT = 'amp.http.client.har.timings.wait';
+    public const TIME_RECEIVE = 'amp.http.client.har.timings.receive';
+    public const TIME_COMPLETE = 'amp.http.client.har.timings.complete';
+}
diff --git a/src/HttpClientBuilder.php b/src/HttpClientBuilder.php
index 5d1a393e..d0411274 100644
--- a/src/HttpClientBuilder.php
+++ b/src/HttpClientBuilder.php
@@ -7,6 +7,8 @@
 use Amp\Http\Client\Interceptor\DecompressResponse;
 use Amp\Http\Client\Interceptor\FollowRedirects;
 use Amp\Http\Client\Interceptor\ForbidUriUserInfo;
+use Amp\Http\Client\Interceptor\RecordServerIp;
+use Amp\Http\Client\Interceptor\RecordStartTime;
 use Amp\Http\Client\Interceptor\RetryRequests;
 use Amp\Http\Client\Interceptor\SetRequestHeaderIfUnset;
 use Amp\Http\Client\Internal\ForbidCloning;
@@ -59,6 +61,7 @@ public function build(): HttpClient
         $client = $client->intercept(new SetRequestHeaderIfUnset('accept', '*/*'));
         $client = $client->intercept(new SetRequestHeaderIfUnset('user-agent', 'amphp/http-client @ v4.x'));
         $client = $client->intercept(new DecompressResponse);
+        $client = $client->intercept(new RecordServerIp);
 
         foreach (\array_reverse($this->applicationInterceptors) as $interceptor) {
             $client = new InterceptedHttpClient($client, $interceptor);
@@ -76,7 +79,7 @@ public function build(): HttpClient
             $client = new InterceptedHttpClient($client, $this->forbidUriUserInfo);
         }
 
-        return $client;
+        return new InterceptedHttpClient($client, new RecordStartTime);
     }
 
     /**
diff --git a/src/Interceptor/LogIntoHttpArchive.php b/src/Interceptor/LogIntoHttpArchive.php
new file mode 100644
index 00000000..80d48f2f
--- /dev/null
+++ b/src/Interceptor/LogIntoHttpArchive.php
@@ -0,0 +1,204 @@
+<?php
+
+namespace Amp\Http\Client\Interceptor;
+
+use Amp\CancellationToken;
+use Amp\File;
+use Amp\Http\Client\ApplicationInterceptor;
+use Amp\Http\Client\DelegateHttpClient;
+use Amp\Http\Client\HarAttributes;
+use Amp\Http\Client\HttpException;
+use Amp\Http\Client\Request;
+use Amp\Http\Client\Response;
+use Amp\Http\Message;
+use Amp\Promise;
+use Amp\Sync\LocalMutex;
+use Amp\Sync\Lock;
+use function Amp\call;
+use function Amp\Promise\rethrow;
+
+final class LogIntoHttpArchive implements ApplicationInterceptor
+{
+    private static function getTime(Request $request, string $start, string $end): int
+    {
+        if (!$request->hasAttribute($start) || !$request->hasAttribute($end)) {
+            return -1;
+        }
+
+        return $request->getAttribute($end) - $request->getAttribute($start);
+    }
+
+    private static function formatHeaders(Message $message): array
+    {
+        $headers = [];
+
+        foreach ($message->getHeaders() as $field => $values) {
+            foreach ($values as $value) {
+                $headers[] = [
+                    'name' => $field,
+                    'value' => $value,
+                ];
+            }
+        }
+
+        return $headers;
+    }
+
+    private static function formatEntry(Response $response): array
+    {
+        $request = $response->getRequest();
+
+        $data = [
+            'startedDateTime' => $request->getAttribute(HarAttributes::STARTED_DATE_TIME)->format(\DateTimeInterface::RFC3339_EXTENDED),
+            'time' => self::getTime($request, HarAttributes::TIME_START, HarAttributes::TIME_COMPLETE),
+            'request' => [
+                'method' => $request->getMethod(),
+                'url' => (string) $request->getUri()->withUserInfo(''),
+                'httpVersion' => 'http/' . $request->getProtocolVersions()[0],
+                'headers' => self::formatHeaders($request),
+                'queryString' => [],
+                'cookies' => [],
+                'headersSize' => -1,
+                'bodySize' => -1,
+            ],
+            'response' => [
+                'status' => $response->getStatus(),
+                'statusText' => $response->getReason(),
+                'httpVersion' => 'http/' . $response->getProtocolVersion(),
+                'headers' => self::formatHeaders($response),
+                'cookies' => [],
+                'redirectURL' => $response->getHeader('location') ?? '',
+                'headersSize' => -1,
+                'bodySize' => -1,
+                'content' => [
+                    'size' => (int) ($response->getHeader('content-length') ?? '-1'),
+                    'mimeType' => $response->getHeader('content-type') ?? '',
+                ],
+            ],
+            'cache' => [],
+            'timings' => [
+                'blocked' => self::getTime(
+                    $request,
+                    HarAttributes::TIME_START,
+                    HarAttributes::TIME_CONNECT
+                ),
+                'dns' => -1,
+                'connect' => self::getTime(
+                    $request,
+                    HarAttributes::TIME_CONNECT,
+                    HarAttributes::TIME_SEND
+                ),
+                'ssl' => self::getTime(
+                    $request,
+                    HarAttributes::TIME_SSL,
+                    HarAttributes::TIME_SEND
+                ),
+                'send' => self::getTime(
+                    $request,
+                    HarAttributes::TIME_SEND,
+                    HarAttributes::TIME_WAIT
+                ),
+                'wait' => self::getTime(
+                    $request,
+                    HarAttributes::TIME_WAIT,
+                    HarAttributes::TIME_RECEIVE
+                ),
+                'receive' => self::getTime(
+                    $request,
+                    HarAttributes::TIME_RECEIVE,
+                    HarAttributes::TIME_COMPLETE
+                ),
+            ],
+        ];
+
+        if ($request->hasAttribute(HarAttributes::SERVER_IP_ADDRESS)) {
+            $data['serverIPAddress'] = $request->getAttribute(HarAttributes::SERVER_IP_ADDRESS);
+        }
+
+        return $data;
+    }
+
+    /** @var LocalMutex */
+    private $fileMutex;
+    /** @var File\File|null */
+    private $fileHandle;
+    /** @var string */
+    private $filePath;
+    /** @var \Throwable|null */
+    private $error;
+
+    public function __construct(string $filePath)
+    {
+        $this->filePath = $filePath;
+        $this->fileMutex = new LocalMutex;
+    }
+
+    public function request(Request $request, CancellationToken $cancellation, DelegateHttpClient $next): Promise
+    {
+        return call(function () use ($request, $cancellation, $next) {
+            if ($this->error) {
+                throw $this->error;
+            }
+
+            /** @var Response $response */
+            $response = yield $next->request($request, $cancellation);
+
+            rethrow($this->writeLog($response));
+
+            return $response;
+        });
+    }
+
+    public function reset(): Promise
+    {
+        return call(function () {
+            /** @var Lock $lock */
+            $lock = yield $this->fileMutex->acquire();
+
+            // Will automatically reopen and reset the file
+            $this->fileHandle = null;
+            $this->error = null;
+
+            $lock->release();
+        });
+    }
+
+    private function writeLog(Response $response): Promise
+    {
+        return call(function () use ($response) {
+            try {
+                yield $response->getTrailers();
+            } catch (\Throwable $e) {
+                // ignore, still log the remaining response times
+            }
+
+            try {
+                /** @var Lock $lock */
+                $lock = yield $this->fileMutex->acquire();
+
+                $firstEntry = $this->fileHandle === null;
+
+                if ($firstEntry) {
+                    $this->fileHandle = yield File\open($this->filePath, 'w');
+
+                    $header = '{"log":{"version":"1.2","creator":{"name":"amphp/http-client","version":"4.x"},"pages":[],"entries":[';
+
+                    yield $this->fileHandle->write($header);
+                } else {
+                    yield $this->fileHandle->seek(-3, \SEEK_CUR);
+                }
+
+                /** @noinspection PhpComposerExtensionStubsInspection */
+                $json = \json_encode(self::formatEntry($response));
+
+                yield $this->fileHandle->write(($firstEntry ? '' : ',') . $json . ']}}');
+
+                $lock->release();
+            } catch (HttpException $e) {
+                $this->error = $e;
+            } catch (\Throwable $e) {
+                $this->error = new HttpException('Writing HTTP archive log failed', 0, $e);
+            }
+        });
+    }
+}
diff --git a/src/Interceptor/RecordServerIp.php b/src/Interceptor/RecordServerIp.php
new file mode 100644
index 00000000..870fedd9
--- /dev/null
+++ b/src/Interceptor/RecordServerIp.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Amp\Http\Client\Interceptor;
+
+use Amp\CancellationToken;
+use Amp\Http\Client\Connection\Stream;
+use Amp\Http\Client\HarAttributes;
+use Amp\Http\Client\NetworkInterceptor;
+use Amp\Http\Client\Request;
+use Amp\Promise;
+
+final class RecordServerIp implements NetworkInterceptor
+{
+    public function requestViaNetwork(Request $request, CancellationToken $cancellation, Stream $stream): Promise
+    {
+        $host = $stream->getRemoteAddress()->getHost();
+        if (\strrpos($host, ':')) {
+            $host = '[' . $host . ']';
+        }
+
+        $request->setAttribute(HarAttributes::SERVER_IP_ADDRESS, $host);
+
+        return $stream->request($request, $cancellation);
+    }
+}
diff --git a/src/Interceptor/RecordStartTime.php b/src/Interceptor/RecordStartTime.php
new file mode 100644
index 00000000..1774e257
--- /dev/null
+++ b/src/Interceptor/RecordStartTime.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Amp\Http\Client\Interceptor;
+
+use Amp\CancellationToken;
+use Amp\Http\Client\ApplicationInterceptor;
+use Amp\Http\Client\DelegateHttpClient;
+use Amp\Http\Client\HarAttributes;
+use Amp\Http\Client\Request;
+use Amp\Promise;
+use function Amp\getCurrentTime;
+
+final class RecordStartTime implements ApplicationInterceptor
+{
+    public function request(Request $request, CancellationToken $cancellation, DelegateHttpClient $next): Promise
+    {
+        $request->setAttribute(HarAttributes::STARTED_DATE_TIME, new \DateTimeImmutable);
+        $request->setAttribute(HarAttributes::TIME_START, getCurrentTime());
+
+        return $next->request($request, $cancellation);
+    }
+}
diff --git a/test/Interceptor/InterceptorTest.php b/test/Interceptor/InterceptorTest.php
index 6a232f6a..57455e1c 100644
--- a/test/Interceptor/InterceptorTest.php
+++ b/test/Interceptor/InterceptorTest.php
@@ -73,6 +73,7 @@ final protected function whenRequestIsExecuted(?ClientRequest $request = null):
             $this->response = $response;
 
             yield $this->response->getBody()->buffer();
+            yield $this->response->getTrailers();
 
             yield $this->server->stop();
 
diff --git a/test/Interceptor/LogIntoHttpArchiveTest.php b/test/Interceptor/LogIntoHttpArchiveTest.php
new file mode 100644
index 00000000..87835ce7
--- /dev/null
+++ b/test/Interceptor/LogIntoHttpArchiveTest.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace Amp\Http\Client\Interceptor;
+
+use Amp\Http\Client\Request;
+
+class LogIntoHttpArchiveTest extends InterceptorTest
+{
+    public function testProducesValidJson(): \Generator
+    {
+        $filePath = \tempnam(\sys_get_temp_dir(), 'amphp-http-client-test-');
+        $logger = new LogIntoHttpArchive($filePath);
+
+        $this->givenApplicationInterceptor($logger);
+
+        yield $this->whenRequestIsExecuted(new Request('http://example.com/foo/bar?test=1'));
+        yield $logger->reset(); // awaits write because of the mutex
+
+        $jsonLog = \file_get_contents($filePath);
+
+        $this->assertJson($jsonLog);
+    }
+}