diff --git a/src/emitter/SapiEmitter.php b/src/emitter/SapiEmitter.php
index 9f8b5957..d4a29faf 100644
--- a/src/emitter/SapiEmitter.php
+++ b/src/emitter/SapiEmitter.php
@@ -6,7 +6,7 @@
 
 use Psr\Http\Message\{ResponseInterface, StreamInterface};
 use yii\base\InvalidArgumentException;
-use yii2\extensions\psrbridge\emitter\exception\{HeadersAlreadySentException, Message, OutputAlreadySentException};
+use yii2\extensions\psrbridge\exception\{HeadersAlreadySentException, Message, OutputAlreadySentException};
 
 use function implode;
 use function ob_get_length;
diff --git a/src/emitter/exception/HeadersAlreadySentException.php b/src/exception/HeadersAlreadySentException.php
similarity index 96%
rename from src/emitter/exception/HeadersAlreadySentException.php
rename to src/exception/HeadersAlreadySentException.php
index c07c8277..7d14185e 100644
--- a/src/emitter/exception/HeadersAlreadySentException.php
+++ b/src/exception/HeadersAlreadySentException.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace yii2\extensions\psrbridge\emitter\exception;
+namespace yii2\extensions\psrbridge\exception;
 
 use yii\base\Exception;
 
diff --git a/src/emitter/exception/Message.php b/src/exception/Message.php
similarity index 98%
rename from src/emitter/exception/Message.php
rename to src/exception/Message.php
index 2ea59757..72ea1e15 100644
--- a/src/emitter/exception/Message.php
+++ b/src/exception/Message.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace yii2\extensions\psrbridge\emitter\exception;
+namespace yii2\extensions\psrbridge\exception;
 
 /**
  * Represents standardized error messages for HTTP exceptions.
diff --git a/src/emitter/exception/OutputAlreadySentException.php b/src/exception/OutputAlreadySentException.php
similarity index 96%
rename from src/emitter/exception/OutputAlreadySentException.php
rename to src/exception/OutputAlreadySentException.php
index eb90784a..4b53eab9 100644
--- a/src/emitter/exception/OutputAlreadySentException.php
+++ b/src/exception/OutputAlreadySentException.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace yii2\extensions\psrbridge\emitter\exception;
+namespace yii2\extensions\psrbridge\exception;
 
 use yii\base\Exception;
 
diff --git a/tests/emitter/SapiEmitterTest.php b/tests/emitter/SapiEmitterTest.php
index 814d7c1e..3e9817e3 100644
--- a/tests/emitter/SapiEmitterTest.php
+++ b/tests/emitter/SapiEmitterTest.php
@@ -9,8 +9,8 @@
 use PHPUnit\Framework\TestCase;
 use Psr\Http\Message\{ResponseInterface, StreamInterface};
 use yii\base\InvalidArgumentException;
-use yii2\extensions\psrbridge\emitter\exception\{HeadersAlreadySentException, Message, OutputAlreadySentException};
 use yii2\extensions\psrbridge\emitter\SapiEmitter;
+use yii2\extensions\psrbridge\exception\{HeadersAlreadySentException, Message, OutputAlreadySentException};
 use yii2\extensions\psrbridge\tests\provider\EmitterProvider;
 use yii2\extensions\psrbridge\tests\support\FactoryHelper;
 use yii2\extensions\psrbridge\tests\support\stub\HTTPFunctions;
@@ -682,7 +682,7 @@ public function testThrowExceptionWhenHeadersAlreadySent(): void
         HTTPFunctions::set_headers_sent(true, 'file', 123);
 
         $this->expectException(HeadersAlreadySentException::class);
-        $this->expectExceptionMessage('Unable to emit response; headers already sent.');
+        $this->expectExceptionMessage(Message::UNABLE_TO_EMIT_RESPONSE_HEADERS_ALREADY_SENT->getMessage());
 
         (new SapiEmitter())->emit(FactoryHelper::createResponse());
     }
@@ -700,7 +700,7 @@ public function testThrowExceptionWhenOutputAlreadySent(): void
 
         $this->expectOutputString('Contents');
         $this->expectException(OutputAlreadySentException::class);
-        $this->expectExceptionMessage('Unable to emit response; output has been emitted previously.');
+        $this->expectExceptionMessage(Message::UNABLE_TO_EMIT_OUTPUT_HAS_BEEN_EMITTED->getMessage());
 
         (new SapiEmitter())->emit($response);
     }