Master HTTP Status Codes

The ultimate developer reference for understanding, debugging, and implementing HTTP status codes.

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Explore the five classes of HTTP status codes.

The request was received, continuing process.

The action was successfully received, understood, and accepted.

Further action must be taken in order to complete the request.

The request contains bad syntax or cannot be fulfilled.

The server failed to fulfil an apparently valid request.

The initial part of the request was received; the client should proceed with sending the body.

The server accepts the request to upgrade the connection to a different protocol.

The server has received and is processing the request, but no response is available yet.

Allows the server to send Link headers before the main response, prompting the browser to preload assets.

APIs that return a 200 status code with an error payload break standard HTTP semantics and confuse caching layers.

401 means "Unauthenticated" (who are you?), while 403 means "Unauthorized" (you don't have permission).

If the URL exists but the HTTP method (e.g. POST) is wrong, return 405 Method Not Allowed, not 404.

Bad vs Good API Response

// ❌ BAD
HTTP/1.1 200 OK
{
  "success": false,
  "error": "User not found"
}

// ✅ GOOD
HTTP/1.1 404 Not Found
{
  "error": {
    "code": "user_not_found",
    "message": "The requested user does not exist."
  }
}

Stop guessing and start implementing perfect HTTP semantics today.