diff --git a/webapp/php/src/AbstractHandler.php b/webapp/php/src/AbstractHandler.php
new file mode 100644
index 000000000..eede44c9f
--- /dev/null
+++ b/webapp/php/src/AbstractHandler.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace IsuPipe;
+
+use JsonSerializable;
+use Psr\Http\Message\ResponseInterface as Response;
+
+abstract class AbstractHandler
+{
+    public function jsonResponse(Response $response, array|JsonSerializable $data, int $status = 200): Response
+    {
+        $response->getBody()->write(json_encode($data));
+
+        return $response->withHeader('Content-Type', 'application/json')
+            ->withStatus($status);
+    }
+}
diff --git a/webapp/php/src/InitializeHandler.php b/webapp/php/src/InitializeHandler.php
index 02530ffea..f6b8b385f 100644
--- a/webapp/php/src/InitializeHandler.php
+++ b/webapp/php/src/InitializeHandler.php
@@ -8,7 +8,7 @@
 /**
  * FIXME: ポータルと足並み揃えて修正
  */
-class InitializeHandler
+class InitializeHandler extends AbstractHandler
 {
     public function __invoke(Request $request, Response $response): Response
     {
diff --git a/webapp/php/src/Livecomment/Handler.php b/webapp/php/src/Livecomment/Handler.php
index 2e83ea511..0b062988b 100644
--- a/webapp/php/src/Livecomment/Handler.php
+++ b/webapp/php/src/Livecomment/Handler.php
@@ -4,10 +4,11 @@
 
 namespace IsuPipe\Livecomment;
 
+use IsuPipe\AbstractHandler;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
     public function getLivecommentsHandler(Request $request, Response $response): Response
     {
diff --git a/webapp/php/src/Livestream/Handler.php b/webapp/php/src/Livestream/Handler.php
index 2d161348f..3e0150ed5 100644
--- a/webapp/php/src/Livestream/Handler.php
+++ b/webapp/php/src/Livestream/Handler.php
@@ -4,10 +4,11 @@
 
 namespace IsuPipe\Livestream;
 
+use IsuPipe\AbstractHandler;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
     public function reserveLivestreamHandler(Request $request, Response $response): Response
     {
diff --git a/webapp/php/src/Payment/Handler.php b/webapp/php/src/Payment/Handler.php
index dfddfe5d0..514bd4783 100644
--- a/webapp/php/src/Payment/Handler.php
+++ b/webapp/php/src/Payment/Handler.php
@@ -4,10 +4,11 @@
 
 namespace IsuPipe\Payment;
 
+use IsuPipe\AbstractHandler;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
     public function getPaymentResult(Request $request, Response $response): Response
     {
diff --git a/webapp/php/src/Reaction/Handler.php b/webapp/php/src/Reaction/Handler.php
index c521beaae..7d08365cc 100644
--- a/webapp/php/src/Reaction/Handler.php
+++ b/webapp/php/src/Reaction/Handler.php
@@ -4,10 +4,11 @@
 
 namespace IsuPipe\Reaction;
 
+use IsuPipe\AbstractHandler;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
     public function getReactionsHandler(Request $request, Response $response): Response
     {
diff --git a/webapp/php/src/Stats/Handler.php b/webapp/php/src/Stats/Handler.php
index a04255974..568006899 100644
--- a/webapp/php/src/Stats/Handler.php
+++ b/webapp/php/src/Stats/Handler.php
@@ -4,10 +4,11 @@
 
 namespace IsuPipe\Stats;
 
+use IsuPipe\AbstractHandler;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
     public function getUserStatisticsHandler(Request $request, Response $response): Response
     {
diff --git a/webapp/php/src/Top/Handler.php b/webapp/php/src/Top/Handler.php
index 6313e15b7..36aee690b 100644
--- a/webapp/php/src/Top/Handler.php
+++ b/webapp/php/src/Top/Handler.php
@@ -4,11 +4,18 @@
 
 namespace IsuPipe\Top;
 
+use IsuPipe\AbstractHandler;
+use PDO;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
+    public function __construct(
+        private PDO $db,
+    ) {
+    }
+
     public function getTagHandler(Request $request, Response $response): Response
     {
         // TODO: 実装
diff --git a/webapp/php/src/User/Handler.php b/webapp/php/src/User/Handler.php
index 85a550ae1..460e1830e 100644
--- a/webapp/php/src/User/Handler.php
+++ b/webapp/php/src/User/Handler.php
@@ -4,10 +4,11 @@
 
 namespace IsuPipe\User;
 
+use IsuPipe\AbstractHandler;
 use Psr\Http\Message\ResponseInterface as Response;
 use Psr\Http\Message\ServerRequestInterface as Request;
 
-class Handler
+class Handler extends AbstractHandler
 {
     public function getIconHandler(Request $request, Response $response): Response
     {