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HTTP Status Codes online

Complete HTTP status code reference - searchable

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by
CHUNKY
MUNSTER

Searching the HTTP Status Codes Reference

  1. Type a code number (404), a name (not found) or a keyword from the description (redirect) into the search box.
  2. The list filters live as you type - every match across number, name and description is shown.
  3. Each entry is colour-coded by family: blue 1xx, green 2xx, orange 3xx, red 4xx, purple 5xx.
  4. Read the one-line meaning to decide which code fits your situation.

HTTP Status Codes Reference: a technical lookup for every standard server response code used in modern web architecture. This status code lookup guide helps developers and SEOs understand the difference between permanent and temporary redirects or client versus server errors. It provides a searchable interface for all REST API responses, ensuring you return the correct signal to browsers and crawlers alike.

Understanding Server Response Codes

The first digit of any code indicates its primary purpose: 1xx for informational headers, 2xx for success states like 200 OK, 3xx for redirects, 4xx for client-side issues, and 5xx for server-side failures. This status code reference is an essential tool for debugging network requests and configuring server behavior. Use it to verify that your application is communicating correctly with the global web infrastructure.

Frequently Asked Questions

What is the difference between 301 and 302?

301 Moved Permanently tells browsers and search engines the new URL is the canonical one - they should update bookmarks and link equity. 302 Found is a temporary redirect - the resource is somewhere else for now but the original URL still belongs. Use 301 for site moves and HTTPS upgrades, 302 for short-term diversions.

When should an API return 401 versus 403?

401 Unauthorized means the request is missing or has bad credentials - the client should authenticate and retry. 403 Forbidden means the credentials are valid but the user is not allowed to access this resource - re-authenticating won't help. Sending 403 when you mean 401 will hide a fixable client-side problem.

What does 422 mean and how is it different from 400?

422 Unprocessable Entity means the request was well-formed JSON or XML but failed validation rules (e.g. email format wrong, required field missing). 400 Bad Request means the server couldn't even parse the body. Use 422 for validation errors so clients can distinguish syntax problems from semantic ones.

Why does my API see 502 Bad Gateway intermittently?

502 means the proxy or load balancer in front of your app received an invalid response from the upstream server - usually because the app crashed mid-request, exceeded a timeout, or was restarted during deploy. Check upstream logs around the timestamp; it's almost never a problem with the proxy itself.

Keep your web services healthy by bookmarking this HTTP Status Codes Reference for quick API debugging sessions.

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