ErrorFindly
2032xx SuccessLow

HTTP 203 Non-Authoritative Information

Defined in RFC 7231

What Does HTTP 203 Mean?

The request was successful but the enclosed payload has been modified by a transforming proxy from the origin server's 200 OK response.

Common Causes

  1. 1Proxy or CDN modifying response headers or body
  2. 2Mirror site serving cached but slightly altered content
  3. 3Content transformation by intermediary

Impact

  • ⚠Content may differ slightly from the original source
  • ⚠Metadata may have been modified by a proxy

Developer Fix

For web developers and application engineers

  1. 1Verify response data integrity when 203 is received
  2. 2Compare with direct origin requests if accuracy is critical
  3. 3Consider using end-to-end encryption for sensitive data

Server Admin Fix

For system administrators and DevOps engineers

  1. 1Review proxy transformation rules
  2. 2Ensure intermediaries are not unintentionally modifying content
  3. 3Configure proper cache headers

Frequently Asked Questions

Is 203 commonly used?
No, 203 is rarely used in practice. Most proxies that modify content still return 200. It exists mainly for transparency about content transformation.
Should I worry about getting a 203 response?
Generally no. It indicates the content was slightly modified by an intermediary, but the request was still successful. Check if your proxy or CDN configuration is as expected.

Related HTTP Status Codes

200OK

About the Author

Web Infrastructure Team

Verified against official RFC specifications and real-world server configurations. HTTP status code behavior confirmed across Apache, Nginx, and Cloudflare.