diff --git a/examples/custromString.php b/examples/custromString.php
index a513daa..4bc0a13 100644
--- a/examples/custromString.php
+++ b/examples/custromString.php
@@ -3,11 +3,11 @@
 declare(strict_types=1);
 
 use DawidMazurek\JsonRpc\handler\MethodCallableHandler;
-use DawidMazurek\JsonRpc\io\CustomStringInput;
-use DawidMazurek\JsonRpc\io\InputStream;
-use DawidMazurek\JsonRpc\io\JsonSerializer;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
-use DawidMazurek\JsonRpc\server\JsonRpcServer;
+use DawidMazurek\JsonRpc\IO\CustomStringInput;
+use DawidMazurek\JsonRpc\IO\InputStream;
+use DawidMazurek\JsonRpc\IO\JsonSerializer;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Server\JsonRpcServer;
 
 include __DIR__ . '/../vendor/autoload.php';
 $requestBuilder = new JsonRpcRequestBuilder(new JsonSerializer());
diff --git a/examples/postInput.php b/examples/postInput.php
index b2d7e25..ee69e5e 100644
--- a/examples/postInput.php
+++ b/examples/postInput.php
@@ -3,10 +3,10 @@
 declare(strict_types=1);
 
 use DawidMazurek\JsonRpc\handler\MethodCallableHandler;
-use DawidMazurek\JsonRpc\io\InputStream;
-use DawidMazurek\JsonRpc\io\JsonSerializer;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
-use DawidMazurek\JsonRpc\server\JsonRpcServer;
+use DawidMazurek\JsonRpc\IO\InputStream;
+use DawidMazurek\JsonRpc\IO\JsonSerializer;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Server\JsonRpcServer;
 
 include __DIR__ . '/../vendor/autoload.php';
 $requestBuilder = new JsonRpcRequestBuilder(new JsonSerializer());
diff --git a/src/error/JsonRpcErrorCodes.php b/src/Error/JsonRpcErrorCodes.php
similarity index 86%
rename from src/error/JsonRpcErrorCodes.php
rename to src/Error/JsonRpcErrorCodes.php
index b0bbecc..26356b5 100644
--- a/src/error/JsonRpcErrorCodes.php
+++ b/src/Error/JsonRpcErrorCodes.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\error;
+namespace DawidMazurek\JsonRpc\Error;
 
 class JsonRpcErrorCodes
 {
diff --git a/src/exception/InvalidParams.php b/src/Exception/InvalidParams.php
similarity index 72%
rename from src/exception/InvalidParams.php
rename to src/Exception/InvalidParams.php
index 6ec4e7a..69b1ac8 100644
--- a/src/exception/InvalidParams.php
+++ b/src/Exception/InvalidParams.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 
 class InvalidParams extends JsonRpcException
 {
diff --git a/src/exception/InvalidRequest.php b/src/Exception/InvalidRequest.php
similarity index 73%
rename from src/exception/InvalidRequest.php
rename to src/Exception/InvalidRequest.php
index 5327d6d..7127419 100644
--- a/src/exception/InvalidRequest.php
+++ b/src/Exception/InvalidRequest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 
 class InvalidRequest extends JsonRpcException
 {
diff --git a/src/exception/JsonRpcException.php b/src/Exception/JsonRpcException.php
similarity index 70%
rename from src/exception/JsonRpcException.php
rename to src/Exception/JsonRpcException.php
index 5af1b0e..c8755c7 100644
--- a/src/exception/JsonRpcException.php
+++ b/src/Exception/JsonRpcException.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
 use Exception;
 
diff --git a/src/exception/MethodNotFound.php b/src/Exception/MethodNotFound.php
similarity index 73%
rename from src/exception/MethodNotFound.php
rename to src/Exception/MethodNotFound.php
index 05e915d..f67ea8c 100644
--- a/src/exception/MethodNotFound.php
+++ b/src/Exception/MethodNotFound.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 
 class MethodNotFound extends JsonRpcException
 {
diff --git a/src/exception/ParseError.php b/src/Exception/ParseError.php
similarity index 72%
rename from src/exception/ParseError.php
rename to src/Exception/ParseError.php
index 98478eb..292d7a0 100644
--- a/src/exception/ParseError.php
+++ b/src/Exception/ParseError.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 
 class ParseError extends JsonRpcException
 {
diff --git a/src/handler/JsonRpcRequestHandler.php b/src/Handler/JsonRpcRequestHandler.php
similarity index 60%
rename from src/handler/JsonRpcRequestHandler.php
rename to src/Handler/JsonRpcRequestHandler.php
index 5ee1f6c..1149789 100644
--- a/src/handler/JsonRpcRequestHandler.php
+++ b/src/Handler/JsonRpcRequestHandler.php
@@ -2,11 +2,11 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\handler;
+namespace DawidMazurek\JsonRpc\Handler;
 
-use DawidMazurek\JsonRpc\exception\JsonRpcException;
-use DawidMazurek\JsonRpc\request\JsonRpcRequest;
-use DawidMazurek\JsonRpc\response\JsonRpcResponse;
+use DawidMazurek\JsonRpc\Exception\JsonRpcException;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequest;
+use DawidMazurek\JsonRpc\Response\JsonRpcResponse;
 
 interface JsonRpcRequestHandler
 {
diff --git a/src/handler/MethodCallableHandler.php b/src/Handler/MethodCallableHandler.php
similarity index 80%
rename from src/handler/MethodCallableHandler.php
rename to src/Handler/MethodCallableHandler.php
index 1bbc224..d931ffb 100644
--- a/src/handler/MethodCallableHandler.php
+++ b/src/Handler/MethodCallableHandler.php
@@ -2,16 +2,16 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\handler;
+namespace DawidMazurek\JsonRpc\Handler;
 
-use DawidMazurek\JsonRpc\exception\JsonRpcException;
-use DawidMazurek\JsonRpc\exception\MethodNotFound;
-use DawidMazurek\JsonRpc\request\JsonRpcRequest;
-use DawidMazurek\JsonRpc\request\Request;
-use DawidMazurek\JsonRpc\response\FailedResponse;
-use DawidMazurek\JsonRpc\response\JsonRpcResponse;
-use DawidMazurek\JsonRpc\response\NotificationResponse;
-use DawidMazurek\JsonRpc\response\Response;
+use DawidMazurek\JsonRpc\Exception\JsonRpcException;
+use DawidMazurek\JsonRpc\Exception\MethodNotFound;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequest;
+use DawidMazurek\JsonRpc\Request\Request;
+use DawidMazurek\JsonRpc\Response\FailedResponse;
+use DawidMazurek\JsonRpc\Response\JsonRpcResponse;
+use DawidMazurek\JsonRpc\Response\NotificationResponse;
+use DawidMazurek\JsonRpc\Response\Response;
 
 class MethodCallableHandler implements JsonRpcRequestHandler
 {
diff --git a/src/io/CustomStringInput.php b/src/IO/CustomStringInput.php
similarity index 79%
rename from src/io/CustomStringInput.php
rename to src/IO/CustomStringInput.php
index 3f47307..e9e1028 100644
--- a/src/io/CustomStringInput.php
+++ b/src/IO/CustomStringInput.php
@@ -2,10 +2,10 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\request\JsonRpcRequestAggregate;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestAggregate;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
 
 class CustomStringInput implements JsonRpcInput
 {
diff --git a/src/io/InputStream.php b/src/IO/InputStream.php
similarity index 78%
rename from src/io/InputStream.php
rename to src/IO/InputStream.php
index 293c495..50ecc78 100644
--- a/src/io/InputStream.php
+++ b/src/IO/InputStream.php
@@ -2,10 +2,10 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\request\JsonRpcRequestAggregate;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestAggregate;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
 
 class InputStream implements JsonRpcInput
 {
diff --git a/src/io/JsonRpcInput.php b/src/IO/JsonRpcInput.php
similarity index 50%
rename from src/io/JsonRpcInput.php
rename to src/IO/JsonRpcInput.php
index 151a7b4..7392480 100644
--- a/src/io/JsonRpcInput.php
+++ b/src/IO/JsonRpcInput.php
@@ -1,8 +1,8 @@
 <?php
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\request\JsonRpcRequestAggregate;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestAggregate;
 
 interface JsonRpcInput
 {
diff --git a/src/io/JsonSerializer.php b/src/IO/JsonSerializer.php
similarity index 82%
rename from src/io/JsonSerializer.php
rename to src/IO/JsonSerializer.php
index 5d4df62..93257f4 100644
--- a/src/io/JsonSerializer.php
+++ b/src/IO/JsonSerializer.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\exception\ParseError;
+use DawidMazurek\JsonRpc\Exception\ParseError;
 
 class JsonSerializer
 {
diff --git a/src/request/IdentifiedJsonRpcRequest.php b/src/Request/IdentifiedJsonRpcRequest.php
similarity index 77%
rename from src/request/IdentifiedJsonRpcRequest.php
rename to src/Request/IdentifiedJsonRpcRequest.php
index 4d0046a..04c993b 100644
--- a/src/request/IdentifiedJsonRpcRequest.php
+++ b/src/Request/IdentifiedJsonRpcRequest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 interface IdentifiedJsonRpcRequest extends JsonRpcRequest
 {
diff --git a/src/request/JsonRpcRequest.php b/src/Request/JsonRpcRequest.php
similarity index 82%
rename from src/request/JsonRpcRequest.php
rename to src/Request/JsonRpcRequest.php
index c5ec2ce..daed92f 100644
--- a/src/request/JsonRpcRequest.php
+++ b/src/Request/JsonRpcRequest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 interface JsonRpcRequest
 {
diff --git a/src/request/JsonRpcRequestAggregate.php b/src/Request/JsonRpcRequestAggregate.php
similarity index 89%
rename from src/request/JsonRpcRequestAggregate.php
rename to src/Request/JsonRpcRequestAggregate.php
index 69bb883..7d6f472 100644
--- a/src/request/JsonRpcRequestAggregate.php
+++ b/src/Request/JsonRpcRequestAggregate.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 class JsonRpcRequestAggregate
 {
diff --git a/src/request/JsonRpcRequestBuilder.php b/src/Request/JsonRpcRequestBuilder.php
similarity index 92%
rename from src/request/JsonRpcRequestBuilder.php
rename to src/Request/JsonRpcRequestBuilder.php
index 17e761a..247d063 100644
--- a/src/request/JsonRpcRequestBuilder.php
+++ b/src/Request/JsonRpcRequestBuilder.php
@@ -2,10 +2,10 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
-use DawidMazurek\JsonRpc\exception\InvalidParams;
-use DawidMazurek\JsonRpc\io\JsonSerializer;
+use DawidMazurek\JsonRpc\Exception\InvalidParams;
+use DawidMazurek\JsonRpc\IO\JsonSerializer;
 
 class JsonRpcRequestBuilder
 {
diff --git a/src/request/Notification.php b/src/Request/Notification.php
similarity index 94%
rename from src/request/Notification.php
rename to src/Request/Notification.php
index 06b3aa8..729cbf1 100644
--- a/src/request/Notification.php
+++ b/src/Request/Notification.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 class Notification implements JsonRpcRequest
 {
diff --git a/src/request/Request.php b/src/Request/Request.php
similarity index 95%
rename from src/request/Request.php
rename to src/Request/Request.php
index ce3d511..99726ec 100644
--- a/src/request/Request.php
+++ b/src/Request/Request.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 class Request implements IdentifiedJsonRpcRequest
 {
diff --git a/src/response/FailedResponse.php b/src/Response/FailedResponse.php
similarity index 94%
rename from src/response/FailedResponse.php
rename to src/Response/FailedResponse.php
index 661205c..9e6699f 100644
--- a/src/response/FailedResponse.php
+++ b/src/Response/FailedResponse.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 class FailedResponse implements JsonRpcResponse
 {
diff --git a/src/response/JsonRpcResponse.php b/src/Response/JsonRpcResponse.php
similarity index 72%
rename from src/response/JsonRpcResponse.php
rename to src/Response/JsonRpcResponse.php
index e1c4858..540022b 100644
--- a/src/response/JsonRpcResponse.php
+++ b/src/Response/JsonRpcResponse.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 interface JsonRpcResponse
 {
diff --git a/src/response/JsonRpcResponseAggregate.php b/src/Response/JsonRpcResponseAggregate.php
similarity index 95%
rename from src/response/JsonRpcResponseAggregate.php
rename to src/Response/JsonRpcResponseAggregate.php
index 5be9f56..7891ca5 100644
--- a/src/response/JsonRpcResponseAggregate.php
+++ b/src/Response/JsonRpcResponseAggregate.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 class JsonRpcResponseAggregate
 {
diff --git a/src/response/NotificationResponse.php b/src/Response/NotificationResponse.php
similarity index 80%
rename from src/response/NotificationResponse.php
rename to src/Response/NotificationResponse.php
index bb60c84..0ebf722 100644
--- a/src/response/NotificationResponse.php
+++ b/src/Response/NotificationResponse.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 class NotificationResponse implements JsonRpcResponse
 {
diff --git a/src/response/Response.php b/src/Response/Response.php
similarity index 93%
rename from src/response/Response.php
rename to src/Response/Response.php
index a2a4305..df6592e 100644
--- a/src/response/Response.php
+++ b/src/Response/Response.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 class Response implements JsonRpcResponse
 {
diff --git a/src/server/JsonRpcServer.php b/src/Server/JsonRpcServer.php
similarity index 75%
rename from src/server/JsonRpcServer.php
rename to src/Server/JsonRpcServer.php
index 39929f4..96206bb 100644
--- a/src/server/JsonRpcServer.php
+++ b/src/Server/JsonRpcServer.php
@@ -2,12 +2,12 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\server;
+namespace DawidMazurek\JsonRpc\Server;
 
-use DawidMazurek\JsonRpc\exception\JsonRpcException;
-use DawidMazurek\JsonRpc\handler\JsonRpcRequestHandler;
-use DawidMazurek\JsonRpc\io\JsonRpcInput;
-use DawidMazurek\JsonRpc\response\JsonRpcResponseAggregate;
+use DawidMazurek\JsonRpc\Exception\JsonRpcException;
+use DawidMazurek\JsonRpc\Handler\JsonRpcRequestHandler;
+use DawidMazurek\JsonRpc\IO\JsonRpcInput;
+use DawidMazurek\JsonRpc\Response\JsonRpcResponseAggregate;
 
 class JsonRpcServer
 {
diff --git a/tests/integration/JsonRpcServerIntegrationTest.php b/tests/integration/JsonRpcServerIntegrationTest.php
index 7394c63..993b125 100644
--- a/tests/integration/JsonRpcServerIntegrationTest.php
+++ b/tests/integration/JsonRpcServerIntegrationTest.php
@@ -2,12 +2,12 @@
 
 declare(strict_types = 1);
 
-use DawidMazurek\JsonRpc\handler\MethodCallableHandler;
-use DawidMazurek\JsonRpc\io\CustomStringInput;
-use DawidMazurek\JsonRpc\io\JsonSerializer;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
-use DawidMazurek\JsonRpc\response\JsonRpcResponseAggregate;
-use DawidMazurek\JsonRpc\server\JsonRpcServer;
+use DawidMazurek\JsonRpc\Handler\MethodCallableHandler;
+use DawidMazurek\JsonRpc\IO\CustomStringInput;
+use DawidMazurek\JsonRpc\IO\JsonSerializer;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Response\JsonRpcResponseAggregate;
+use DawidMazurek\JsonRpc\Server\JsonRpcServer;
 use PHPUnit\Framework\TestCase;
 
 class JsonRpcServerIntegrationTest extends TestCase
diff --git a/tests/unit/exception/InvalidParamsTest.php b/tests/unit/Exception/InvalidParamsTest.php
similarity index 82%
rename from tests/unit/exception/InvalidParamsTest.php
rename to tests/unit/Exception/InvalidParamsTest.php
index 2ae5e4b..1f29f24 100644
--- a/tests/unit/exception/InvalidParamsTest.php
+++ b/tests/unit/Exception/InvalidParamsTest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 use PHPUnit\Framework\TestCase;
 
 class InvalidParamsTest extends TestCase
diff --git a/tests/unit/exception/InvalidRequestTest.php b/tests/unit/Exception/InvalidRequestTest.php
similarity index 82%
rename from tests/unit/exception/InvalidRequestTest.php
rename to tests/unit/Exception/InvalidRequestTest.php
index be54cce..0d3b48b 100644
--- a/tests/unit/exception/InvalidRequestTest.php
+++ b/tests/unit/Exception/InvalidRequestTest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 use PHPUnit\Framework\TestCase;
 
 class InvalidRequestTest extends TestCase
diff --git a/tests/unit/exception/MethodNotFoundTest.php b/tests/unit/Exception/MethodNotFoundTest.php
similarity index 82%
rename from tests/unit/exception/MethodNotFoundTest.php
rename to tests/unit/Exception/MethodNotFoundTest.php
index ad3f41b..f036d4e 100644
--- a/tests/unit/exception/MethodNotFoundTest.php
+++ b/tests/unit/Exception/MethodNotFoundTest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 use PHPUnit\Framework\TestCase;
 
 class MethodNotFoundTest extends TestCase
diff --git a/tests/unit/exception/ParseErrorTest.php b/tests/unit/Exception/ParseErrorTest.php
similarity index 82%
rename from tests/unit/exception/ParseErrorTest.php
rename to tests/unit/Exception/ParseErrorTest.php
index 9fbbffb..8aae7bd 100644
--- a/tests/unit/exception/ParseErrorTest.php
+++ b/tests/unit/Exception/ParseErrorTest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\exception;
+namespace DawidMazurek\JsonRpc\Exception;
 
-use DawidMazurek\JsonRpc\error\JsonRpcErrorCodes;
+use DawidMazurek\JsonRpc\Error\JsonRpcErrorCodes;
 use PHPUnit\Framework\TestCase;
 
 class ParseErrorTest extends TestCase
diff --git a/tests/unit/handler/MethodCallableHandlerTest.php b/tests/unit/Handler/MethodCallableHandlerTest.php
similarity index 88%
rename from tests/unit/handler/MethodCallableHandlerTest.php
rename to tests/unit/Handler/MethodCallableHandlerTest.php
index 8f0ec2a..9948380 100644
--- a/tests/unit/handler/MethodCallableHandlerTest.php
+++ b/tests/unit/Handler/MethodCallableHandlerTest.php
@@ -2,15 +2,15 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\handler;
-
-use DawidMazurek\JsonRpc\exception\ParseError;
-use DawidMazurek\JsonRpc\request\JsonRpcRequest;
-use DawidMazurek\JsonRpc\request\Notification;
-use DawidMazurek\JsonRpc\request\Request;
-use DawidMazurek\JsonRpc\response\FailedResponse;
-use DawidMazurek\JsonRpc\response\NotificationResponse;
-use DawidMazurek\JsonRpc\response\Response;
+namespace DawidMazurek\JsonRpc\Handler;
+
+use DawidMazurek\JsonRpc\Exception\ParseError;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequest;
+use DawidMazurek\JsonRpc\Request\Notification;
+use DawidMazurek\JsonRpc\Request\Request;
+use DawidMazurek\JsonRpc\Response\FailedResponse;
+use DawidMazurek\JsonRpc\Response\NotificationResponse;
+use DawidMazurek\JsonRpc\Response\Response;
 use PHPUnit\Framework\TestCase;
 
 class MethodCallableHandlerTest extends TestCase
diff --git a/tests/unit/io/CustomStringInputTest.php b/tests/unit/IO/CustomStringInputTest.php
similarity index 85%
rename from tests/unit/io/CustomStringInputTest.php
rename to tests/unit/IO/CustomStringInputTest.php
index ebf1b9a..d26da02 100644
--- a/tests/unit/io/CustomStringInputTest.php
+++ b/tests/unit/IO/CustomStringInputTest.php
@@ -2,10 +2,10 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\request\JsonRpcRequestAggregate;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestAggregate;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
 use PHPUnit\Framework\TestCase;
 
 class CustomStringInputTest extends TestCase
diff --git a/tests/unit/io/InputStreamTest.php b/tests/unit/IO/InputStreamTest.php
similarity index 86%
rename from tests/unit/io/InputStreamTest.php
rename to tests/unit/IO/InputStreamTest.php
index f8ef308..6b0a2e1 100644
--- a/tests/unit/io/InputStreamTest.php
+++ b/tests/unit/IO/InputStreamTest.php
@@ -3,10 +3,10 @@
 declare(strict_types = 1);
 
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\request\JsonRpcRequestAggregate;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestBuilder;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestAggregate;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestBuilder;
 use PHPUnit\Framework\TestCase;
 
 function file_get_contents()
diff --git a/tests/unit/io/JsonSerializerTest.php b/tests/unit/IO/JsonSerializerTest.php
similarity index 92%
rename from tests/unit/io/JsonSerializerTest.php
rename to tests/unit/IO/JsonSerializerTest.php
index 8999cb4..814946d 100644
--- a/tests/unit/io/JsonSerializerTest.php
+++ b/tests/unit/IO/JsonSerializerTest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\io;
+namespace DawidMazurek\JsonRpc\IO;
 
-use DawidMazurek\JsonRpc\exception\ParseError;
+use DawidMazurek\JsonRpc\Exception\ParseError;
 use PHPUnit\Framework\TestCase;
 
 class JsonSerializerTest extends TestCase
diff --git a/tests/unit/request/JsonRpcRequestBuilderTest.php b/tests/unit/Request/JsonRpcRequestBuilderTest.php
similarity index 96%
rename from tests/unit/request/JsonRpcRequestBuilderTest.php
rename to tests/unit/Request/JsonRpcRequestBuilderTest.php
index b1d2bdf..4bec356 100644
--- a/tests/unit/request/JsonRpcRequestBuilderTest.php
+++ b/tests/unit/Request/JsonRpcRequestBuilderTest.php
@@ -2,9 +2,9 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
-use DawidMazurek\JsonRpc\io\JsonSerializer;
+use DawidMazurek\JsonRpc\IO\JsonSerializer;
 use PHPUnit\Framework\TestCase;
 
 class JsonRpcRequestBuilderTest extends TestCase
diff --git a/tests/unit/request/NotificationTest.php b/tests/unit/Request/NotificationTest.php
similarity index 93%
rename from tests/unit/request/NotificationTest.php
rename to tests/unit/Request/NotificationTest.php
index 5dc6384..9c605f9 100644
--- a/tests/unit/request/NotificationTest.php
+++ b/tests/unit/Request/NotificationTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 use PHPUnit\Framework\TestCase;
 
diff --git a/tests/unit/request/RequestTest.php b/tests/unit/Request/RequestTest.php
similarity index 94%
rename from tests/unit/request/RequestTest.php
rename to tests/unit/Request/RequestTest.php
index 077b375..86acd33 100644
--- a/tests/unit/request/RequestTest.php
+++ b/tests/unit/Request/RequestTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\request;
+namespace DawidMazurek\JsonRpc\Request;
 
 use PHPUnit\Framework\TestCase;
 
diff --git a/tests/unit/response/FailedResponseTest.php b/tests/unit/Response/FailedResponseTest.php
similarity index 94%
rename from tests/unit/response/FailedResponseTest.php
rename to tests/unit/Response/FailedResponseTest.php
index 8b15133..b1a31f5 100644
--- a/tests/unit/response/FailedResponseTest.php
+++ b/tests/unit/Response/FailedResponseTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 use PHPUnit\Framework\TestCase;
 
diff --git a/tests/unit/response/JsonRpcResponseAggregateTest.php b/tests/unit/Response/JsonRpcResponseAggregateTest.php
similarity index 98%
rename from tests/unit/response/JsonRpcResponseAggregateTest.php
rename to tests/unit/Response/JsonRpcResponseAggregateTest.php
index 7cdfff8..aa9d1af 100644
--- a/tests/unit/response/JsonRpcResponseAggregateTest.php
+++ b/tests/unit/Response/JsonRpcResponseAggregateTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 use PHPUnit\Framework\TestCase;
 
diff --git a/tests/unit/response/NotificationResponseTest.php b/tests/unit/Response/NotificationResponseTest.php
similarity index 88%
rename from tests/unit/response/NotificationResponseTest.php
rename to tests/unit/Response/NotificationResponseTest.php
index 311fa4b..28d95e0 100644
--- a/tests/unit/response/NotificationResponseTest.php
+++ b/tests/unit/Response/NotificationResponseTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 use PHPUnit\Framework\TestCase;
 
diff --git a/tests/unit/response/ResponseTest.php b/tests/unit/Response/ResponseTest.php
similarity index 93%
rename from tests/unit/response/ResponseTest.php
rename to tests/unit/Response/ResponseTest.php
index 19f5dc8..bce1cfa 100644
--- a/tests/unit/response/ResponseTest.php
+++ b/tests/unit/Response/ResponseTest.php
@@ -2,7 +2,7 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\response;
+namespace DawidMazurek\JsonRpc\Response;
 
 use PHPUnit\Framework\TestCase;
 
diff --git a/tests/unit/server/JsonRpcServerTest.php b/tests/unit/Server/JsonRpcServerTest.php
similarity index 89%
rename from tests/unit/server/JsonRpcServerTest.php
rename to tests/unit/Server/JsonRpcServerTest.php
index 0db425a..62c12a8 100644
--- a/tests/unit/server/JsonRpcServerTest.php
+++ b/tests/unit/Server/JsonRpcServerTest.php
@@ -2,14 +2,14 @@
 
 declare(strict_types = 1);
 
-namespace DawidMazurek\JsonRpc\server;
-
-use DawidMazurek\JsonRpc\exception\ParseError;
-use DawidMazurek\JsonRpc\handler\JsonRpcRequestHandler;
-use DawidMazurek\JsonRpc\io\JsonRpcInput;
-use DawidMazurek\JsonRpc\request\JsonRpcRequestAggregate;
-use DawidMazurek\JsonRpc\request\Request;
-use DawidMazurek\JsonRpc\response\JsonRpcResponse;
+namespace DawidMazurek\JsonRpc\Server;
+
+use DawidMazurek\JsonRpc\Exception\ParseError;
+use DawidMazurek\JsonRpc\Handler\JsonRpcRequestHandler;
+use DawidMazurek\JsonRpc\IO\JsonRpcInput;
+use DawidMazurek\JsonRpc\Request\JsonRpcRequestAggregate;
+use DawidMazurek\JsonRpc\Request\Request;
+use DawidMazurek\JsonRpc\Response\JsonRpcResponse;
 use PHPUnit\Framework\TestCase;
 
 class JsonRpcServerTest extends TestCase