HTTP Status Codes
Quick reference for HTTP response status codes with descriptions
About HTTP Status Codes
Lists 30 commonly used HTTP status codes, from 100 Continue to 504 Gateway Timeout, each with its reason phrase, a one-line description and a color for its class. Typing in the search box filters by number, phrase or description, so 42 or timeout narrows the list instantly. Useful when choosing a response code for an API or reading one in server logs.
Category: API.
Frequently asked questions
Which codes are listed, and what do the 1xx to 5xx classes mean?
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The list covers 30 common codes across all five classes: 1xx informational, 2xx success, 3xx redirection, 4xx client error (the request was wrong) and 5xx server error (the server failed to fulfill a valid request). Less common codes such as 303 See Other, 418 or 451 aren't included.
What's the difference between 301 and 302?
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301 is a permanent redirect — browsers and search engines update their records to the new URL. 302 is temporary — the original URL should be kept. Use 301 for SEO-sensitive redirects.
What's the difference between 401 and 403?
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401 Unauthorized means the request lacks valid authentication credentials — the client should log in. 403 Forbidden means the server understood the request but refuses to authorize it — even with valid credentials.
When should I return 400 vs 422?
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Return 400 Bad Request when the request itself is malformed, such as a body with invalid JSON syntax. Return 422 Unprocessable Entity when the syntax is valid but the content fails validation, like a missing required field or an end date before the start date; many APIs simply use 400 for both.