HTTP 203 Non-Authoritative Information vs 409 Conflict
HTTP 203 (Non-Authoritative Information) is a 2xx Success response, while 409 (Conflict) is a 4xx Client Error response. 203 indicates that the response payload has been modified by a transforming proxy from the origin server's 200 response. In contrast, 409 means that the request conflicts with the current state of the server. Often due to concurrent modification or business rule violations.
Description
The response payload has been modified by a transforming proxy from the origin server's 200 response.
When You See It
When a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
How to Fix
Check if a proxy is modifying the response. Access the origin directly if you need the original content.
Description
The request conflicts with the current state of the server. Often due to concurrent modification or business rule violations.
When You See It
When trying to create a resource that already exists, or updating a resource that was modified by another request.
How to Fix
Refresh the resource state, resolve conflicts, and retry. Use ETags for optimistic concurrency.
Key Differences
203 is a 2xx Success response, while 409 is a 4xx Client Error response.
HTTP 203: The response payload has been modified by a transforming proxy from the origin server's 200 response.
HTTP 409: The request conflicts with the current state of the server. Often due to concurrent modification or business rule violations.
You encounter 203 when when a proxy or CDN modifies the response body (e.g., adds headers, transforms content).
You encounter 409 when when trying to create a resource that already exists, or updating a resource that was modified by another request.
When to Use Which
For 203 (Non-Authoritative Information): Check if a proxy is modifying the response. Access the origin directly if you need the original content. For 409 (Conflict): Refresh the resource state, resolve conflicts, and retry. Use ETags for optimistic concurrency.