Networking6 min read

Complete HTTP Status Codes Reference Guide for REST APIs

A developer-friendly guide explaining 1xx, 2xx, 3xx, 4xx, and 5xx HTTP response status codes with REST API best practices.

DevOnlineTools Team

Backend Engineering

2026-08-03

Interactive Utility

Instant browser execution. 100% private with zero server data sent.

Overview of HTTP Response Status Codes

HTTP status codes indicate whether a specific HTTP request has been successfully completed. Responses are grouped into five classes:

1xx Informational: Request received, continuing process.

2xx Success: Action successfully received, understood, and accepted.

3xx Redirection: Further action must be taken to complete request.

4xx Client Error: Request contains bad syntax or cannot be fulfilled.

5xx Server Error: Server failed to fulfill an apparently valid request.

200

Standard response for successful HTTP requests. The actual response payload will depend on the request method used.

201

The request has been fulfilled and resulted in a new resource being created (e.g., POST /api/users).

400

The server cannot process the request due to malformed syntax, invalid parameters, or client payload errors.

401

Authentication is required or credentials provided were invalid.

403

The client is authenticated but lacks permission rights to access the requested resource.

404

The requested resource could not be found on the server.

429

The client has exceeded the allowed rate limit within a given timeframe.

500

A generic error message returned when an unexpected server exception occurs.