What are HTTP status codes?

HTTP status codes are three-digit numbers returned by a server in response to a client's request. They indicate whether the request was successful (2xx), needs redirection (3xx), had a client error (4xx), or encountered a server error (5xx).

What is the difference between 401 and 403?

401 Unauthorized means the client is not authenticated — the server doesn't know who you are. 403 Forbidden means the server knows who you are but won't allow access. Authentication fixes 401; authorization fixes 403.

What causes a 500 Internal Server Error?

A 500 error indicates something went wrong on the server side. Common causes include unhandled exceptions, database connection failures, misconfigured server settings, or bugs in server-side code.

What's the difference between 301 and 302 redirects?

301 Moved Permanently tells browsers and search engines that the URL has permanently changed. 302 Found indicates a temporary redirect. Use 301 for permanent URL changes (better for SEO), 302 for temporary moves.

What does 429 Too Many Requests mean?

429 means you've exceeded the rate limit set by the API or server. The response typically includes a Retry-After header telling you how long to wait before making another request. This is commonly encountered when using APIs.

HTTPステータスコード

HTTPステータスコードを検索し、説明・使用例・サンプルを確認できます。1xx〜5xxコードの完全リファレンス。

1xxInformational

2xxSuccess

3xxRedirection

4xxClient Errors

5xxServer Errors

使い方

HTTPステータスコードを検索し、説明・使用例・サンプルを確認できます。1xx〜5xxコードの完全リファレンス。

1Use the search bar to find a specific status code by number or name.
2Click category buttons (1xx, 2xx, 3xx, 4xx, 5xx) to filter by type.
3Click on any code to see its full description and use cases.
4Copy the code number to use in documentation or API responses.

主な機能

Complete reference for all standard HTTP status codes
Organized by category: 1xx, 2xx, 3xx, 4xx, 5xx
Search by code number or description
Detailed explanations with real-world use cases

HTTPステータスコード

使い方

主な機能

よくある質問