diff --git a/src/main/php/web/Response.class.php b/src/main/php/web/Response.class.php
index e9842bdd..1a6a18f3 100755
--- a/src/main/php/web/Response.class.php
+++ b/src/main/php/web/Response.class.php
@@ -12,6 +12,7 @@
  */
 class Response {
   private $output;
+  private $streaming= null;
   private $flushed= false;
   private $status= 200;
   private $message= 'OK';
@@ -109,13 +110,30 @@ public function headers() {
     return $r;
   }
 
-  /** @param web.io.Output $output */
+  /**
+   * Begins output by sending the status line and headers
+   *
+   * @param  web.io.Output $output
+   * @return web.io.Output
+   */
   private function begin($output) {
     $output->begin($this->status, $this->message, $this->cookies
-      ? array_merge($this->headers, ['Set-Cookie' => array_map(function($c) { return $c->header(); }, $this->cookies)])
+      ? $this->headers + ['Set-Cookie' => array_map(function($c) { return $c->header(); }, $this->cookies)]
       : $this->headers
     );
     $this->flushed= true;
+    return $output;
+  }
+
+  /**
+   * Changes the implementation used inside `stream()` to determine the output.
+   *
+   * @param  function(self, ?int): web.io.Output $implementation
+   * @return self
+   */
+  public function streaming(callable $implementation) {
+    $this->streaming= $implementation;
+    return $this;
   }
 
   /**
@@ -129,7 +147,7 @@ public function flush() {
       throw new IllegalStateException('Response already flushed');
     }
 
-    $this->begin($this->output);
+    $this->begin($this->streaming ? ($this->streaming)($this, 0) : $this->output);
   }
 
   /**
@@ -152,26 +170,20 @@ public function end() {
   }
 
   /**
-   * Returns a stream to write on
+   * Returns a stream to write on: When given a length, sets the `Content-Length`
+   * header to this value and writes the subsequently given bytes unmodified to
+   * the output. Otheriwse, chunked transfer encoding is used.
    *
-   * @param  int $size If omitted, uses chunked transfer encoding
+   * @param  ?int $length
    * @return io.streams.OutputStream
    * @throws lang.IllegalStateException
    */
-  public function stream($size= null) {
+  public function stream($length= null) {
     if ($this->flushed) {
       throw new IllegalStateException('Response already flushed');
     }
 
-    if (null === $size) {
-      $output= $this->output->stream();
-    } else {
-      $this->headers['Content-Length']= [$size];
-      $output= $this->output;
-    }
-
-    $this->begin($output);
-    return $output;
+    return $this->begin($this->streaming ? ($this->streaming)($this, $length) : $this->output->stream($length));
   }
 
   /**
diff --git a/src/main/php/web/io/Buffered.class.php b/src/main/php/web/io/Buffered.class.php
index eadabd24..caa8dce3 100755
--- a/src/main/php/web/io/Buffered.class.php
+++ b/src/main/php/web/io/Buffered.class.php
@@ -1,14 +1,12 @@
 <?php namespace web\io;
 
-/**
- * Buffers data
- */
+/** Buffers data */
 class Buffered extends Output {
   private $target;
   private $status, $message, $headers;
   private $buffer= '';
 
-  /** @param web.io.Output $target */
+  /** @param parent $target */
   public function __construct($target) {
     $this->target= $target;
   }
diff --git a/src/main/php/web/io/Output.class.php b/src/main/php/web/io/Output.class.php
index 85e8bc1f..2d1e8da1 100755
--- a/src/main/php/web/io/Output.class.php
+++ b/src/main/php/web/io/Output.class.php
@@ -36,9 +36,10 @@ public abstract function write($bytes);
    * Returns an output used when the content-length is not known at the
    * time of starting the output.
    *
+   * @param  ?int $length
    * @return self
    */
-  public function stream() { return $this; }
+  public function stream($length= null) { return $this; }
 
   /** @return void */
   public function finish() { }
@@ -47,7 +48,7 @@ public function finish() { }
   public function flush() { }
 
   /** @return void */
-  public function close() {
+  public final function close() {
     if ($this->closed) return;
     $this->finish();
     $this->closed= true;
diff --git a/src/main/php/web/io/TestOutput.class.php b/src/main/php/web/io/TestOutput.class.php
index 9cfc32dd..23dabe6e 100755
--- a/src/main/php/web/io/TestOutput.class.php
+++ b/src/main/php/web/io/TestOutput.class.php
@@ -5,7 +5,7 @@
 /**
  * Input for testing purposes
  *
- * @test  xp://web.unittest.io.TestOutputTest
+ * @test  web.unittest.io.TestOutputTest
  */
 class TestOutput extends Output {
   private $stream;
@@ -53,8 +53,15 @@ public function begin($status, $message, $headers) {
     $this->bytes.= "\r\n";
   }
 
-  /** @return web.io.Output */
-  public function stream() { return $this->stream->newInstance($this); }
+  /**
+   * Returns writer with length if known, using the configured stream otherwise
+   *
+   * @param  ?int $length
+   * @return web.io.Output
+   */
+  public function stream($length= null) {
+    return null === $length ? $this->stream->newInstance($this) : new WriteLength($this, $length);
+  }
 
   /**
    * Writes the bytes (in this case, to the internal buffer which can be
diff --git a/src/main/php/web/io/WriteChunks.class.php b/src/main/php/web/io/WriteChunks.class.php
index f7a43fe9..b5d5128f 100755
--- a/src/main/php/web/io/WriteChunks.class.php
+++ b/src/main/php/web/io/WriteChunks.class.php
@@ -4,15 +4,15 @@
  * Writes Chunked transfer encoding
  *
  * @see   https://tools.ietf.org/html/rfc7230#section-4.1
- * @test  xp://web.unittest.io.WriteChunksTest
+ * @test  web.unittest.io.WriteChunksTest
  */
 class WriteChunks extends Output {
-  const BUFFER_SIZE = 4096;
+  const BUFFER_SIZE= 4096;
 
   private $target;
   private $buffer= '';
 
-  /** @param web.io.Output $target */
+  /** @param parent $target */
   public function __construct($target) {
     $this->target= $target;
   }
diff --git a/src/main/php/web/io/WriteLength.class.php b/src/main/php/web/io/WriteLength.class.php
new file mode 100755
index 00000000..e571a1d4
--- /dev/null
+++ b/src/main/php/web/io/WriteLength.class.php
@@ -0,0 +1,54 @@
+<?php namespace web\io;
+
+/**
+ * Writes content with length by adding `Content-Length` header
+ *
+ * @test  web.unittest.io.WriteLengthTest
+ */
+class WriteLength extends Output {
+  private $target, $length;
+
+  /**
+   * Creates a new instance
+   *
+   * @param  parent $target
+   * @param  int $length
+   */
+  public function __construct($target, $length) {
+    $this->target= $target;
+    $this->length= $length;
+  }
+
+  /**
+   * Begins output
+   *
+   * @param  int $status
+   * @param  string $message
+   * @param  [:string] $headers
+   * @return void
+   */
+  public function begin($status, $message, $headers) {
+    $headers['Content-Length']= [$this->length];
+    $this->target->begin($status, $message, $headers);
+  }
+
+  /**
+   * Writes a chunk of data
+   *
+   * @param  string $chunk
+   * @return void
+   */
+  public function write($chunk) {
+    $this->target->write($chunk);
+  }
+
+  /** @return void */
+  public function flush() {
+    $this->target->flush();
+  }
+
+  /** @return void */
+  public function finish() {
+    $this->target->finish();
+  }
+}
\ No newline at end of file
diff --git a/src/main/php/xp/web/SAPI.class.php b/src/main/php/xp/web/SAPI.class.php
index 19746e7d..abf7da7a 100755
--- a/src/main/php/xp/web/SAPI.class.php
+++ b/src/main/php/xp/web/SAPI.class.php
@@ -1,6 +1,6 @@
 <?php namespace xp\web;
 
-use web\io\{Buffered, Input, Output, Param, ReadStream, ReadLength, WriteChunks, Incomplete};
+use web\io\{Buffered, Input, Output, Param, ReadStream, ReadLength, WriteChunks, WriteLength, Incomplete};
 
 /**
  * Wrapper for PHP's Server API ("SAPI").
@@ -144,17 +144,19 @@ public function read($length= -1) {
    * Uses chunked TE for HTTP/1.1, buffering for HTTP/1.0 or when using
    * Apache and FastCGI, which is broken.
    *
+   * @param  ?int $length
    * @return web.io.Output
    * @see    https://tools.ietf.org/html/rfc2068#section-19.7.1
    * @see    https://bz.apache.org/bugzilla/show_bug.cgi?id=53332
    */
-  public function stream() {
-    $buffered= (
+  public function stream($length= null) {
+    if (null !== $length) return new WriteLength($this, $length);
+
+    $buffered= $_SERVER['SERVER_PROTOCOL'] < 'HTTP/1.1' || (
       isset($_SERVER['GATEWAY_INTERFACE']) &&
       stristr($_SERVER['GATEWAY_INTERFACE'], 'CGI') &&
       stristr($_SERVER['SERVER_SOFTWARE'], 'Apache')
-    ) || $_SERVER['SERVER_PROTOCOL'] < 'HTTP/1.1';
-
+    );
     return $buffered ? new Buffered($this) : new WriteChunks($this);
   }
 
diff --git a/src/main/php/xp/web/dev/Buffer.class.php b/src/main/php/xp/web/dev/Buffer.class.php
deleted file mode 100755
index e0d12c1c..00000000
--- a/src/main/php/xp/web/dev/Buffer.class.php
+++ /dev/null
@@ -1,41 +0,0 @@
-<?php namespace xp\web\dev;
-
-use web\io\Output;
-
-class Buffer extends Output {
-  public $status, $message, $headers= [];
-  public $bytes= '';
-
-  public function begin($status, $message, $headers) {
-    $this->status= $status;
-    $this->message= $message;
-    $this->headers= $headers;
-  }
-
-  public function write($bytes) {
-    $this->bytes.= $bytes;
-  }
-
-  /**
-   * Drain this buffered output to a given output instance, closing it
-   * once finished.
-   *
-   * @param  web.Response $res
-   * @return void
-   */
-  public function drain($res) {
-    $res->answer($this->status, $this->message);
-    foreach ($this->headers as $name => $value) {
-      $res->header($name, $value);
-    }
-
-    if ('' !== $this->bytes) {
-      $out= $res->stream($this->headers['Content-Length'][0] ?? null);
-      try {
-        $out->write($this->bytes);
-      } finally {
-        $out->close();
-      }
-    }
-  }
-}
\ No newline at end of file
diff --git a/src/main/php/xp/web/dev/CaptureOutput.class.php b/src/main/php/xp/web/dev/CaptureOutput.class.php
new file mode 100755
index 00000000..001a9b58
--- /dev/null
+++ b/src/main/php/xp/web/dev/CaptureOutput.class.php
@@ -0,0 +1,71 @@
+<?php namespace xp\web\dev;
+
+use web\io\Output;
+
+class CaptureOutput extends Output {
+  public $status, $message, $headers;
+  public $bytes= '';
+  private $length= -1;
+
+  /**
+   * Sets length
+   *
+   * @param  ?int $length
+   * @return self
+   */
+  public function length($length) {
+    $this->length= $length;
+    return $this;
+  }
+
+  /**
+   * Begins output
+   *
+   * @param  int $status
+   * @param  string $message
+   * @param  [:string] $headers
+   * @return void
+   */
+  public function begin($status, $message, $headers) {
+    $this->status= $status;
+    $this->message= $message;
+    $this->headers= $headers;
+  }
+
+  /**
+   * Writes a chunk of data
+   *
+   * @param  string $chunk
+   * @return void
+   */
+  public function write($bytes) {
+    $this->bytes.= $bytes;
+  }
+
+  /**
+   * Ensure response is flushed
+   *
+   * @param  web.Response $response
+   * @return void
+   */
+  public function end($response) {
+    if (-1 === $this->length) $response->flush();
+  }
+
+  /**
+   * Drain this buffered output to a given output instance, closing it
+   * once finished.
+   *
+   * @param  web.Response $response
+   * @return void
+   */
+  public function drain($response) {
+    $out= $response->output()->stream($this->length);
+    try {
+      $out->begin($this->status, $this->message, $this->headers);
+      $out->write($this->bytes);
+    } finally {
+      $out->close();
+    }
+  }
+}
\ No newline at end of file
diff --git a/src/main/php/xp/web/dev/Console.class.php b/src/main/php/xp/web/dev/Console.class.php
index 1d9beeb4..5ecc879c 100755
--- a/src/main/php/xp/web/dev/Console.class.php
+++ b/src/main/php/xp/web/dev/Console.class.php
@@ -1,6 +1,8 @@
 <?php namespace xp\web\dev;
 
-use web\{Filter, Response};
+use Closure, Throwable as Any;
+use lang\Throwable;
+use web\{Error, Filter};
 
 /**
  * The development console captures content written via `var_dump()`,
@@ -20,20 +22,21 @@ public function __construct($name= 'xp/web/dev/console') {
   }
 
   /**
-   * Creates HTML table rows
+   * Transforms template
    *
-   * @param  [:var] $headers
+   * @param  string $template
+   * @param  [:var] $context
    * @return string
    */
-  private function rows($headers) {
-    $r= '';
-    foreach ($headers as $name => $value) {
-      $r.= '<tr>
-        <td class="name">'.htmlspecialchars($name).'</td>
-        <td class="value">'.htmlspecialchars(implode(', ', $value)).'</td>
-      </tr>';
-    }
-    return $r;
+  private function transform($template, $context) {
+    return preg_replace_callback(
+      '/\{\{([^ }]+) ?([^}]+)?\}\}/',
+      function($m) use($context) {
+        $value= $context[$m[1]] ?? '';
+        return $value instanceof Closure ? $value($context[$m[2]] ?? '') : htmlspecialchars($value);
+      },
+      $template
+    );
   }
 
   /**
@@ -45,30 +48,51 @@ private function rows($headers) {
    * @return var
    */
   public function filter($req, $res, $invocation) {
-    $buffer= new Response(new Buffer());
-
+    $capture= new CaptureOutput();
     try {
       ob_start();
-      yield from $invocation->proceed($req, $buffer);
-    } finally {
-      $buffer->end();
+      yield from $invocation->proceed($req, $res->streaming(function($res, $length) use($capture) {
+        return $capture->length($length);
+      }));
+
+      $kind= 'Debug';
       $debug= ob_get_clean();
+      if (0 === strlen($debug)) return $capture->drain($res);
+    } catch (Any $e) {
+      $kind= 'Error';
+      $res->answer($e instanceof Error ? $e->status() : 500);
+      $debug= ob_get_clean()."\n".Throwable::wrap($e)->toString();
+    } finally {
+      $capture->end($res);
     }
 
-    $res->trace= $buffer->trace;
-    $out= $buffer->output();
-    if (0 === strlen($debug)) {
-      $out->drain($res);
-    } else {
-      $res->status(200, 'Debug');
-      $res->send(sprintf(
-        typeof($this)->getClassLoader()->getResource($this->template),
-        htmlspecialchars($debug),
-        $out->status,
-        htmlspecialchars($out->message),
-        $this->rows($out->headers),
-        htmlspecialchars($out->bytes)
-      ));
+    $console= $this->transform(typeof($this)->getClassLoader()->getResource($this->template), [
+      'kind'     => $kind,
+      'debug'    => $debug,
+      'status'   => $capture->status,
+      'message'  => $capture->message,
+      'headers'  => $capture->headers,
+      'contents' => $capture->bytes,
+      '#rows'    => function($headers) {
+        $r= '';
+        foreach ($headers as $name => $value) {
+          $r.= '<tr>
+            <td class="name">'.htmlspecialchars($name).'</td>
+            <td class="value">'.htmlspecialchars(implode(', ', $value)).'</td>
+          </tr>';
+        }
+        return $r;
+      }
+    ]);
+    $target= $res->output()->stream(strlen($console));
+    try {
+      $target->begin(200, 'Debug', [
+        'Content-Type'  => ['text/html; charset='.\xp::ENCODING],
+        'Cache-Control' => ['no-cache, no-store'],
+      ]);
+      $target->write($console);
+    } finally {
+      $target->close();
     }
   }
 }
\ No newline at end of file
diff --git a/src/main/php/xp/web/dev/console.html b/src/main/php/xp/web/dev/console.html
index 7ff8e308..e62d68bd 100755
--- a/src/main/php/xp/web/dev/console.html
+++ b/src/main/php/xp/web/dev/console.html
@@ -1,12 +1,12 @@
 <!DOCTYPE html>
 <html>
   <head>
-    <title>Debug</title>
+    <title>{{kind}}</title>
     <style type="text/css">
       body         { font-family: "Segoe UI",Arial,Helvetica; background-color: rgb(27, 43, 52); color: rgb(205, 211, 222); }
       #content     { margin: 2em; }
       h1 img       { float: left; margin-right: 0.5em; }
-      h1 #code     { padding: 0.1em 0.5em; background-color: rgb(102, 153, 204); color: white; border-radius: 0.1em; }
+      h1 #code     { padding: 0.1em 0.5em; background-color: rgb(102, 153, 204); color: white; border-radius: 0.1em; text-transform: uppercase; }
       #debug       { border: 1px dotted rgb(205, 211, 222); overflow: hidden; padding: 0.5em; font-size: 13px; }
       button.clip  { float: right; }
       h2 #status   { color: rgb(102, 153, 204); }
@@ -23,19 +23,19 @@
       <h1>
         <img width="59" height="48" src="data:image/png;base64,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" alt="Debug"/>
 
-        <span id="code">DEBUG</span>
+        <span id="code">{{kind}}</span>
       </h1>
       <div id="debug">
         <button class="clip" title="Copy to clipboard" onclick="clip(document.getElementById('output').innerText); flash(document.getElementById('debug'))">📋</button>
-        <pre id="output">%1$s</pre>
+        <pre id="output">{{debug}}</pre>
       </div>
 
       <!-- Original HTTP response -->
-      <h2>HTTP/1.1 <span id="status">%2$d %3$s</span></h2>
+      <h2>HTTP/1.1 <span id="status">{{status}} {{message}}</span></h2>
       <table id="headers">
-        %4$s
+        {{#rows headers}}
       </table>
-      <pre id="body">%5$s</pre>
+      <pre id="body">{{content}}</pre>
     </div>
     <script type="text/javascript">
       function clip(text) {
diff --git a/src/main/php/xp/web/srv/Output.class.php b/src/main/php/xp/web/srv/Output.class.php
index 24287393..616b8ce9 100755
--- a/src/main/php/xp/web/srv/Output.class.php
+++ b/src/main/php/xp/web/srv/Output.class.php
@@ -1,7 +1,7 @@
 <?php namespace xp\web\srv;
 
 use peer\SocketException;
-use web\io\{Buffered, WriteChunks, Output as Base};
+use web\io\{Buffered, WriteChunks, WriteLength, Output as Base};
 
 class Output extends Base {
   private $socket, $version;
@@ -18,13 +18,20 @@ public function __construct($socket, $version= '1.1') {
   }
 
   /**
-   * Uses chunked TE for HTTP/1.1, buffering for HTTP/1.0 
+   * Returns writer with length if known, chunked TE for HTTP/1.1, buffering otherwise
    *
+   * @param  ?int $length
    * @return web.io.Output
    * @see    https://tools.ietf.org/html/rfc2068#section-19.7.1
    */
-  public function stream() {
-    return $this->version < '1.1' ? new Buffered($this) : new WriteChunks($this);
+  public function stream($length= null) {
+    if (null !== $length) {
+      return new WriteLength($this, $length);
+    } else if ($this->version >= '1.1') {
+      return new WriteChunks($this);
+    } else {
+      return new Buffered($this);
+    }
   }
 
   /**
diff --git a/src/test/php/web/unittest/ResponseTest.class.php b/src/test/php/web/unittest/ResponseTest.class.php
index 13b9b4d3..2b4bbd33 100755
--- a/src/test/php/web/unittest/ResponseTest.class.php
+++ b/src/test/php/web/unittest/ResponseTest.class.php
@@ -5,11 +5,33 @@
 use lang\{IllegalArgumentException, IllegalStateException};
 use test\{Assert, Expect, Test, Values};
 use util\URI;
-use web\io\{Buffered, TestOutput};
+use web\io\{Output, Buffered, TestOutput};
 use web\{Cookie, Response};
 
 class ResponseTest {
 
+  /**
+   * Output implementation reversing the written bytes into the given buffer
+   * 
+   * @param  string $buffer
+   * @return web.io.Output
+   */
+  private function reverse(&$buffer) {
+    return new class($buffer) extends Output {
+      private $buffer;
+
+      public function __construct(&$buffer) { $this->buffer= &$buffer; }
+
+      public function begin($status, $message, $headers) { }
+
+      public function write($chunk) { $this->buffer.= strrev($chunk); }
+
+      public function flush() { }
+
+      public function finish() { }
+    };
+  }
+
   /**
    * Assertion helper
    *
@@ -315,4 +337,31 @@ public function flush_twice() {
     $res->flush();
     $res->flush();
   }
+
+  #[Test]
+  public function streaming_with_send() {
+    $res= (new Response(new TestOutput()))->streaming(function($res, $size) use(&$buffer) {
+      return $this->reverse($buffer);
+    });
+
+    $buffer= '';
+    $res->send('Test');
+
+    Assert::equals('tseT', $buffer);
+  }
+
+  #[Test]
+  public function streaming_with_stream() {
+    $res= (new Response(new TestOutput()))->streaming(function($res, $size) use(&$buffer) {
+      return $this->reverse($buffer);
+    });
+
+    $buffer= '';
+    $stream= $res->stream();
+    $stream->write('Test');
+    $stream->write('OK');
+    $stream->close();
+
+    Assert::equals('tseTKO', $buffer);
+  }
 }
\ No newline at end of file
diff --git a/src/test/php/web/unittest/io/WriteChunksTest.class.php b/src/test/php/web/unittest/io/WriteChunksTest.class.php
index fe1bd327..51f5475f 100755
--- a/src/test/php/web/unittest/io/WriteChunksTest.class.php
+++ b/src/test/php/web/unittest/io/WriteChunksTest.class.php
@@ -1,7 +1,6 @@
 <?php namespace web\unittest\io;
 
-use test\Assert;
-use test\Test;
+use test\{Assert, Test};
 use web\io\{TestOutput, WriteChunks};
 
 class WriteChunksTest {
diff --git a/src/test/php/web/unittest/io/WriteLengthTest.class.php b/src/test/php/web/unittest/io/WriteLengthTest.class.php
new file mode 100755
index 00000000..57876a69
--- /dev/null
+++ b/src/test/php/web/unittest/io/WriteLengthTest.class.php
@@ -0,0 +1,67 @@
+<?php namespace web\unittest\io;
+
+use test\{Assert, Test};
+use web\io\{TestOutput, WriteLength};
+
+class WriteLengthTest {
+
+  #[Test]
+  public function can_create() {
+    new WriteLength(new TestOutput(), 0);
+  }
+
+  #[Test]
+  public function zero_content_length() {
+    $out= new TestOutput();
+
+    $w= new WriteLength($out, 0);
+    $w->begin(204, 'No Content', []);
+
+    Assert::equals('Content-Length: 0', $out->headers());
+  }
+
+  #[Test]
+  public function sets_content_length() {
+    $out= new TestOutput();
+
+    $w= new WriteLength($out, 4);
+    $w->begin(200, 'OK', []);
+    $w->write('Test');
+
+    Assert::equals('Content-Length: 4', $out->headers());
+  }
+
+  #[Test]
+  public function overwrites_content_length() {
+    $out= new TestOutput();
+
+    $w= new WriteLength($out, 4);
+    $w->begin(200, 'OK', ['Content-Length' => [6100]]);
+    $w->write('Test');
+
+    Assert::equals('Content-Length: 4', $out->headers());
+  }
+
+  #[Test]
+  public function write_one_chunk() {
+    $out= new TestOutput();
+
+    $w= new WriteLength($out, 4);
+    $w->begin(200, 'OK', []);
+    $w->write('Test');
+
+    Assert::equals('Test', $out->body());
+  }
+
+  #[Test]
+  public function write_two_small_chunks() {
+    $out= new TestOutput();
+
+    $w= new WriteLength($out, 8);
+    $w->begin(200, 'OK', []);
+    $w->write('Unit');
+    $w->write('Test');
+
+    Assert::equals('UnitTest', $out->body());
+  }
+}
\ No newline at end of file
diff --git a/src/test/php/web/unittest/server/ConsoleTest.class.php b/src/test/php/web/unittest/server/ConsoleTest.class.php
index f216b9ee..f85c4999 100755
--- a/src/test/php/web/unittest/server/ConsoleTest.class.php
+++ b/src/test/php/web/unittest/server/ConsoleTest.class.php
@@ -1,8 +1,9 @@
 <?php namespace web\unittest\server;
 
+use lang\IllegalArgumentException;
 use test\{Assert, Test, Values};
 use web\io\{TestInput, TestOutput};
-use web\{Filters, Request, Response};
+use web\{Error, Filters, Request, Response};
 use xp\web\dev\Console;
 
 class ConsoleTest {
@@ -131,4 +132,36 @@ public function headers_appear_in_console() {
       $res->output()->bytes()
     );
   }
+
+  #[Test]
+  public function uncaught_exceptions() {
+    $res= $this->handle(function($req, $res) {
+      throw new IllegalArgumentException('Test');
+    });
+
+    Assert::matches(
+      '/HTTP\/1.1 <span id="status">500 Internal Server Error<\/span>/',
+      $res->output()->bytes()
+    );
+    Assert::matches(
+      '/Exception lang.IllegalArgumentException \(Test\)/',
+      $res->output()->bytes()
+    );
+  }
+
+  #[Test]
+  public function uncaught_errors() {
+    $res= $this->handle(function($req, $res) {
+      throw new Error(404);
+    });
+
+    Assert::matches(
+      '/HTTP\/1.1 <span id="status">404 Not Found<\/span>/',
+      $res->output()->bytes()
+    );
+    Assert::matches(
+      '/Error web.Error\(#404: Not Found\)/',
+      $res->output()->bytes()
+    );
+  }
 }
\ No newline at end of file