HTTP 301 Moved Permanently vs 428 Precondition Required
HTTP 301 (Moved Permanently) is a 3xx Redirection response, while 428 (Precondition Required) is a 4xx Client Error response. 301 indicates that the resource has been permanently moved to a new URL. All future requests should use the new URL. Search engines will transfer link equity to the new URL. In contrast, 428 means that the server requires the request to be conditional (e.g., include If-Match header) to prevent lost updates.
Description
The resource has been permanently moved to a new URL. All future requests should use the new URL. Search engines will transfer link equity to the new URL.
When You See It
After domain migrations, URL restructuring, or when consolidating duplicate URLs.
How to Fix
Update links and bookmarks to the new URL in the Location header. For SEO, this is the preferred redirect for permanent moves.
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.
Key Differences
301 is a 3xx Redirection response, while 428 is a 4xx Client Error response.
HTTP 301: The resource has been permanently moved to a new URL. All future requests should use the new URL. Search engines will transfer link equity to the new URL.
HTTP 428: The server requires the request to be conditional (e.g., include If-Match header) to prevent lost updates.
You encounter 301 when after domain migrations, URL restructuring, or when consolidating duplicate URLs.
You encounter 428 when when an API requires optimistic concurrency control via ETags.
When to Use Which
For 301 (Moved Permanently): Update links and bookmarks to the new URL in the Location header. For SEO, this is the preferred redirect for permanent moves. For 428 (Precondition Required): Fetch the resource first to get its ETag, then include If-Match in your update request.