HTTP 428 Precondition Required vs 500 Internal Server Error
HTTP 428 (Precondition Required) is a 4xx Client Error response, while 500 (Internal Server Error) is a 5xx Server Error response. 428 indicates that the server requires the request to be conditional (e.g., include If-Match header) to prevent lost updates. In contrast, 500 means that the server encountered an unexpected condition that prevented it from fulfilling the request. A generic catch-all for server-side errors.
Description
The server requires the request to be conditional (e.g., include If-Match header) to prevent lost updates.
When You See It
When an API requires optimistic concurrency control via ETags.
How to Fix
Fetch the resource first to get its ETag, then include If-Match in your update request.
Description
The server encountered an unexpected condition that prevented it from fulfilling the request. A generic catch-all for server-side errors.
When You See It
When an unhandled exception occurs, a database connection fails, or server code has a bug.
How to Fix
Check server logs for the stack trace. Common causes: unhandled exceptions, database errors, misconfigurations.
Key Differences
428 is a 4xx Client Error response, while 500 is a 5xx Server Error response.
HTTP 428: The server requires the request to be conditional (e.g., include If-Match header) to prevent lost updates.
HTTP 500: The server encountered an unexpected condition that prevented it from fulfilling the request. A generic catch-all for server-side errors.
You encounter 428 when when an API requires optimistic concurrency control via ETags.
You encounter 500 when when an unhandled exception occurs, a database connection fails, or server code has a bug.
When to Use Which
For 428 (Precondition Required): Fetch the resource first to get its ETag, then include If-Match in your update request. For 500 (Internal Server Error): Check server logs for the stack trace. Common causes: unhandled exceptions, database errors, misconfigurations.