HTTP Status Code Reference
Look up what any HTTP response code means — plain English, no jargon. Search by number or keyword, or browse by category.
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HTTP status codes are three-digit responses your browser and server exchange every time a web page loads. Whether you're debugging a broken page, setting up redirects, or troubleshooting an API, knowing what each code means saves time. This free reference lists every standard HTTP status code with plain-English explanations — no login, no fluff.
How to Use the HTTP Status Code Reference
- Search or browse — Type any status code (like
404) or keyword (like "redirect") in the search bar to filter instantly. - Browse by category — Click a category tab (1xx, 2xx, 3xx, 4xx, 5xx) to see all codes in that group.
- Read the explanation — Each code includes a plain-English description, when it typically occurs, and what to do about it.
- Copy the code — Click the copy icon next to any code to copy it to your clipboard for use in documentation or code.
- Bookmark the page — Save it as your go-to HTTP reference whenever you're debugging web issues.
Why Use Flipper File for HTTP Status Code Lookups?
- Every standard HTTP code covered — All 1xx, 2xx, 3xx, 4xx, and 5xx codes from the official IANA registry, including commonly encountered non-standard codes.
- Instant search — Filter by code number, name, or keyword to find what you need in under a second.
- Plain-English explanations — No RFC jargon. Each code explains what happened, why it happens, and what you should do next.
- 100% free — No login, no account, no email required.
- Works offline-friendly — The full reference loads once and runs entirely in your browser.
- Developer-friendly details — Includes common causes and fix guidance for every error-range code.
Frequently Asked Questions
What are HTTP status codes?
HTTP status codes are standardized three-digit numbers returned by a web server in response to a browser or client request. They tell the client whether the request succeeded, failed, or requires further action. The first digit indicates the category: 1xx (informational), 2xx (success), 3xx (redirection), 4xx (client error), and 5xx (server error).
What does a 200 status code mean?
A 200 OK status code means the request was successful and the server returned the requested resource. It's the most common status code and indicates everything worked as expected.
What does 404 mean?
A 404 Not Found error means the server couldn't find the resource at the requested URL. This can happen because the page was deleted, the URL was mistyped, or the content was moved without a redirect being set up. Fixing a 404 typically means either restoring the content or setting up a 301 redirect to the new location.
What's the difference between a 301 and a 302 redirect?
A 301 Moved Permanently tells browsers and search engines that a page has permanently moved to a new URL. A 302 Found (or Moved Temporarily) signals a temporary move. For SEO purposes, 301 redirects pass link equity to the new URL while 302s generally do not — use 301 for permanent redirects.
What causes a 500 Internal Server Error?
A 500 Internal Server Error is a generic server-side error meaning something went wrong on the server but it can't be more specific. Common causes include misconfigured server software, a bug in server-side code, a failed database connection, or a PHP/Python script crash. Checking server error logs is usually the first step to diagnosing a 500.
What does 403 Forbidden mean?
A 403 Forbidden response means the server understood the request but refuses to authorize it. Unlike a 401 Unauthorized, re-authenticating won't help — the server knows who you are but won't let you access the resource. Common causes include file permission errors, IP blocks, or accessing a protected directory.
What is a 429 status code?
429 Too Many Requests means the client has sent too many requests in a given timeframe and has been rate-limited. The server may include a Retry-After header indicating how long to wait before sending another request. This is commonly seen with APIs that enforce request limits.
What does 503 Service Unavailable mean?
A 503 Service Unavailable response means the server is temporarily unable to handle the request — usually due to server overload or scheduled maintenance. Unlike a 500 error, a 503 implies the problem is temporary and the server expects to recover. The response may include a Retry-After header.