How to Use the HTTP Status Codes Reference & Diagnostic Directory
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1
Type any status code (e.g., 404, 502, 401) or term (e.g., "gateway", "unauthorized", "redirect") into the search bar.
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2
Click any status card to expand detailed RFC specifications, common triggers, and developer resolution steps.
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3
Filter by category pill: Informational (1xx), Successful (2xx), Redirection (3xx), Client Error (4xx), or Server Error (5xx).
Practical Example & Use Case
Common Real-World Scenario
Diagnosing the difference between a `502 Bad Gateway` (upstream server issue) and `504 Gateway Timeout` during API outage troubleshooting.
Technical Notes & Limitations
Browser Engine Architecture
Covers over 60 standardized IETF and IANA HTTP status codes.
Frequently Asked Questions
What is the difference between 401 and 403?
401 Unauthorized means the user is not authenticated (missing/invalid credentials). 403 Forbidden means the user is authenticated but lacks permission to access the resource.