HTTP ステータスコード
すべての HTTP ステータスコードをカテゴリ別に説明付きで検索できます。
100
1xx
Continue
The server has received the request headers and the client should proceed to send the request body.
101
1xx
Switching Protocols
The requester has asked the server to switch protocols and the server has agreed to do so.
200
2xx
OK
The request has succeeded.
201
2xx
Created
The request has succeeded and a new resource has been created as a result.
202
2xx
Accepted
The request has been received but not yet acted upon.
204
2xx
No Content
The server successfully processed the request but is not returning any content.
206
2xx
Partial Content
The server is delivering only part of the resource due to a range header sent by the client.
301
3xx
Moved Permanently
The URL of the requested resource has been changed permanently. The new URL is given in the response.
302
3xx
Found
Tells the client to look at another URL. Temporary redirect.
303
3xx
See Other
The response can be found under a different URL using the GET method.
304
3xx
Not Modified
The resource has not been modified since last request. Cached version is still valid.
307
3xx
Temporary Redirect
Redirect to another URL, preserving request method. Temporary.
308
3xx
Permanent Redirect
Permanent redirect that preserves the request method.
400
4xx
Bad Request
The server could not understand the request due to invalid syntax.
401
4xx
Unauthorized
Authentication is required and has failed or has not yet been provided.
403
4xx
Forbidden
The client does not have access rights to the content.
404
4xx
Not Found
The server can not find the requested resource.
405
4xx
Method Not Allowed
The request method is known by the server but is not supported by the target resource.
408
4xx
Request Timeout
The server would like to shut down this unused connection.
409
4xx
Conflict
The request could not be completed due to a conflict with the current state of the resource.
410
4xx
Gone
Access to the target resource is no longer available and this condition is likely to be permanent.
413
4xx
Payload Too Large
The request entity is larger than the server is willing or able to process.
414
4xx
URI Too Long
The URI requested by the client is longer than the server is willing to interpret.
415
4xx
Unsupported Media Type
The media format of the request is not supported by the server.
422
4xx
Unprocessable Entity
The request was well-formed but was unable to be followed due to semantic errors.
429
4xx
Too Many Requests
The user has sent too many requests in a given amount of time (rate limiting).
500
5xx
Internal Server Error
The server has encountered a situation it does not know how to handle.
501
5xx
Not Implemented
The request method is not supported by the server and cannot be handled.
502
5xx
Bad Gateway
The server, while working as a gateway, received an invalid response from the upstream server.
503
5xx
Service Unavailable
The server is not ready to handle the request. Common causes: maintenance or overloaded.
504
5xx
Gateway Timeout
The server is acting as a gateway and cannot get a response in time.
505
5xx
HTTP Version Not Supported
The HTTP version used in the request is not supported by the server.
このツールについて
HTTP ステータスコードリファレンスは、HTTP プロトコルで定義されたすべての主要なステータスコードをカテゴリ別に整理した参照ツールです。
コードは1xx（情報）、2xx（成功）、3xx（リダイレクト）、4xx（クライアントエラー）、5xx（サーバーエラー）の5つのカテゴリに分類され、各コードの番号、名称、詳細な説明を提供します。
使い方
- 検索ボックスにコード番号、名前、または説明キーワードを入力してください。
- カテゴリフィルターで特定の範囲のコードのみ表示できます。
- コードカードでステータス番号、名称、説明を確認してください。
- 必要なコードを見つけて API 開発やデバッグに活用してください。
活用事例
API レスポンスの適切なステータスコード選択、ウェブサーバーエラーのデバッグ、HTTP プロトコルの学習、REST API ドキュメント作成に活用できます。
よくある質問
- すべての HTTP ステータスコードが含まれていますか？ — はい、RFC 7231 および関連標準で定義された主要なコードをすべて含んでいます。
- 4xx エラーと 5xx エラーの違いは？ — 4xx はクライアント側のエラー（不正なリクエスト、認証失敗など）で、5xx はサーバー側のエラー（内部エラー、過負荷など）です。
- 301 と 302 の違いは？ — 301 は恒久的なリダイレクト（URL が永続的に変更された）で、302 は一時的なリダイレクトです。SEO のために恒久的な移動には 301 を使用してください。