HTTP Status Codes Cheat Sheet
Infrastructure Editor
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Who it's for
- Site owners troubleshooting errors
- Developers
- Support teams
- Anyone diagnosing a broken site
Every response a web server sends back carries a three-digit HTTP status code indicating what happened. This HTTP status codes cheat sheet shows the first digit and what it tells you at a glance — the fastest way to triage a problem before digging into specifics.
HTTP Status Code Ranges
| Range | Meaning | What it tells you |
|---|---|---|
| 2xx | Success | The request worked as expected |
| 3xx | Redirection | The resource has moved; the browser is being sent elsewhere |
| 4xx | Client error | The problem is with the request (bad URL, missing permission, etc.) |
| 5xx | Server error | The problem is on the server, not the visitor’s request |
Most hosting troubleshooting centers on the 5xx range, because those codes mean the server itself failed to complete a valid request. The fault sits with the hosting environment, application, or configuration, not with anything the visitor did wrong.
Common HTTP Status Codes and Their Fixes
| Code | Name | Common cause | Fix |
|---|---|---|---|
| 200 | OK | — | Working as expected |
| 301 | Moved Permanently | URL structure changed | Confirm redirect target is correct |
| 302 | Found (temporary redirect) | Temporary URL change | Confirm it should be temporary, not permanent |
| 400 | Bad Request | Malformed request from the client | Check the URL/form data being submitted |
| 401 | Unauthorized | Missing or invalid authentication | Check login credentials or API keys |
| 403 | Forbidden | Permission denied by the server | Check file permissions |
| 404 | Not Found | Page doesn’t exist at that URL | Check the URL or restore the missing page |
| 429 | Too Many Requests | Rate limit exceeded | Check for a misbehaving script or bot traffic |
| 500 | Internal Server Error | Broad server-side failure — often a plugin, script, or .htaccess error | See 500 error causes & fixes |
| 502 | Bad Gateway | Upstream server sent an invalid response | See 502 error causes & fixes |
| 503 | Service Unavailable | Server temporarily overloaded or in maintenance | See 503 error causes & fixes |
| 504 | Gateway Timeout | Upstream server took too long to respond | See 504 error causes & fixes |
How to Use This HTTP Status Codes Cheat Sheet During an Outage
Identify the code first. Check the browser’s error page, developer tools network tab, or server logs. Once you have the code, its first digit tells you where to look: 4xx means check the request or permissions, 5xx means check the server and application. From there, follow the link to the dedicated page for that specific error, which covers ranked causes and step-by-step fixes.
If the site is fully unreachable rather than returning any status code at all, that’s usually a DNS or connectivity issue rather than an HTTP error. See “this site can’t be reached” and the website down diagnostic checklist instead.
For the full troubleshooting hub these codes belong to, see common web hosting errors. For the resources hub, see web hosting resources.