Try the HTTP Status Code Reference
Look up any HTTP status code (200, 301, 403, 404, 429, 500, 502...) to see its real meaning, category and the most common real-world causes.
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Search "429" -> Too Many Requests: the client has sent too many requests in a given time window (rate limiting); common causes include an API being called too frequently or a bot-protection trigger; the fix is usually to slow down requests or respect a Retry-After header.Open the HTTP Status Code Reference
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What is the HTTP Status Code Reference?
Every response an HTTP server sends starts with a three-digit status code, and every one of those codes is officially defined by web standards (RFC 9110 and related specs) with a specific real meaning — 200 means success, 404 means the resource wasn't found, 500 means the server itself failed. This reference lists every standard code across all five categories (1xx informational, 2xx success, 3xx redirection, 4xx client error, 5xx server error), with its official name, a plain-English explanation, and the most common real-world situations that actually trigger it.
Search by typing a number (like 403) or a keyword (like "not found" or "rate limit") to jump straight to the code you're debugging, instead of scrolling a long static list. Each entry also notes what a developer, and separately what an end user, should typically do when they hit that specific code.
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What you get
All five categories, 1xx through 5xx, with official names and real definitions.
Find the exact code you're troubleshooting instantly.
Not just the spec definition, but the actual situations that typically produce each code in practice.
Plain-English explanations alongside the technical meaning.
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It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
Web and API developers
Quickly confirm what a status code in a log or error message actually means and why it typically happens.
Try it freeQA and support engineers
Explain an error to a non-technical user or triage a bug report faster.
Try it freeStudents learning web development
Understand the real structure and meaning behind HTTP responses beyond just memorizing "404 means not found".
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This utility | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
What's the difference between a 4xx and a 5xx error?
4xx means the client's request itself had a problem (wrong URL, bad input, missing authentication); 5xx means the server received a valid request but failed to process it.
What does 403 actually mean versus 401?
401 Unauthorized means you haven't successfully authenticated at all; 403 Forbidden means you are identified but you don't have permission for that specific resource.
Why do I see 200 but the page still looks broken?
200 only confirms the HTTP request itself succeeded — it says nothing about whether the application logic or page content behind it worked correctly, which is a separate, common source of confusion.
What should I do about a 429 error?
Slow down your request rate and, if the server provides one, respect the Retry-After header rather than immediately retrying.
Is this list official?
Yes, it reflects the standard HTTP status codes defined by RFC 9110 and related IETF specifications used by every web server and browser.
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Search or browse every standard HTTP status code with its real meaning and common causes. Free to use.
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