HTTP Status Code Lookup
Look up HTTP status codes to understand server response meanings.
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Result
Quick Reference
| Code | Name | Category |
|---|---|---|
200 | OK | Success |
201 | Created | Success |
204 | No Content | Success |
301 | Moved Permanently | Redirection |
302 | Found | Redirection |
304 | Not Modified | Redirection |
400 | Bad Request | Client Error |
401 | Unauthorized | Client Error |
403 | Forbidden | Client Error |
404 | Not Found | Client Error |
429 | Too Many Requests | Client Error |
500 | Internal Server Error | Server Error |
502 | Bad Gateway | Server Error |
503 | Service Unavailable | Server Error |
About HTTP Status Code Lookup
This HTTP status lookup tool explains common response codes so you can quickly understand what a server is returning. Enter any standard HTTP status code to see its name and description.
It is useful for debugging API responses, checking redirect behavior, reading server logs, and understanding whether a request failed because of the client, the server, or an upstream service.
HTTP Status Code Categories
| Category | Range | Description |
|---|---|---|
| 1xx Informational | 100-199 | Request received, continuing process |
| 2xx Success | 200-299 | Request successfully received and processed |
| 3xx Redirection | 300-399 | Further action needed to complete request |
| 4xx Client Error | 400-499 | Request contains error or invalid syntax |
| 5xx Server Error | 500-599 | Server failed to fulfill valid request |
Common Status Codes Explained
200 OK Standard success response for GET, POST, PUT, DELETE Response contains requested resource or result 201 Created Resource successfully created (POST response) Location header points to new resource 204 No Content Success but no body to return Common for DELETE operations 301 Moved Permanently Resource has new permanent URL Update bookmarks, SEO transfers 302 Found (Temporary Redirect) Resource temporarily at different URL Keep using original URL next time 304 Not Modified Use cached version (ETag/If-Modified-Since match) No body, saves bandwidth 400 Bad Request Invalid syntax, malformed request Check request format and parameters 401 Unauthorized Authentication required/failed Include valid credentials 403 Forbidden Authenticated but no permission Check access control rules 404 Not Found Resource doesn't exist at URL Check URL path and resource ID 429 Too Many Requests Rate limit exceeded Wait and retry (check Retry-After) 500 Internal Server Error Generic server error Check server logs for details 502 Bad Gateway Upstream server returned invalid response Check proxy/backend health 503 Service Unavailable Server temporarily overloaded/maintenance Retry later (check Retry-After) 504 Gateway Timeout Upstream server didn't respond in time Increase timeout or check backend
Frequently Asked Questions
- What are HTTP status codes?
- HTTP status codes are 3-digit numbers returned by servers to indicate the result of an HTTP request. They are grouped into 5 categories: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), 5xx (Server Error). The first digit defines the class, remaining two provide specific details.
- What does 200 OK mean?
- 200 OK is the standard success response. It indicates the request was received, understood, and processed successfully. GET requests return the requested resource, POST requests return the result of processing, PUT/PATCH return confirmation of updates.
- What is the difference between 401 and 403?
- 401 Unauthorized means authentication is required but missing or invalid (you need to log in). 403 Forbidden means authentication succeeded but you lack permission for this resource (you're logged in but not authorized). 401 = who are you? 403 = you're not allowed.
- What does 404 Not Found mean?
- 404 Not Found means the server cannot locate the requested resource. The URL might be mistyped, the resource was deleted, or the path is incorrect. Unlike 403 (exists but forbidden) or 500 (server error), 404 specifically means the resource doesn't exist at that location.
- What is the difference between 301 and 302?
- 301 Moved Permanently tells clients to update bookmarks/links to the new URL (SEO-friendly, cached). 302 Found is a temporary redirect; clients should continue using the original URL for future requests. Use 301 for permanent moves, 302 for temporary maintenance or A/B tests.
- What causes 500 Internal Server Error?
- 500 Internal Server Error is a generic server error when no specific code applies. Causes include: code exceptions, database connection failures, configuration errors, resource exhaustion. Check server logs for details. 502/503/504 provide more specific information about the failure.