X-Redirect-By

The HTTP X-Redirect-By response header is an unofficial HTTP header identifying which application or plugin initiated a redirect.

Usage

The X-Redirect-By header appears alongside the Location header in redirect responses. The value names the software component responsible for the redirect, making redirect chains easier to trace and debug.

WordPress introduced the header in core through the wp_redirect() function. When WordPress itself performs a redirect, the value is WordPress. Plugins override this value through the x_redirect_by filter hook, allowing each plugin to identify its own redirects. The header has since been adopted by other platforms like TYPO3.

The header is most common in the WordPress ecosystem, where SEO plugins, multilingual plugins, and redirect managers all produce redirects. Knowing which component triggered a 301 or 302 response saves time when diagnosing unexpected redirect behavior or redirect loops.

Values

The value is a free-form string identifying the application or plugin responsible for the redirect. Common values from production data include:

WordPress

The WordPress value means WordPress core initiated the redirect. This covers canonical URL redirects, trailing slash normalization, and old slug redirects handled by WordPress itself.

Plugin names

Plugin-specific values identify which installed plugin triggered the redirect. Frequently observed values include redirection (the Redirection plugin), Rank Math, Yoast SEO Premium, Polylang Pro, WPML, and Permalink Manager.

Example

A permanent redirect issued by WordPress core includes the header with the value WordPress. The Location header shows the target URL while X-Redirect-By confirms WordPress core handled the redirect.

HTTP/1.1 301 Moved Permanently
Location: https://example.re/new-page/
X-Redirect-By: WordPress

When a redirect plugin handles the response, the header value changes to identify the plugin. Here the Redirection plugin performed a temporary redirect.

HTTP/1.1 302 Found
Location: https://example.re/destination/
X-Redirect-By: redirection

An SEO plugin managing URL redirects identifies itself in the header. Rank Math uses its own name as the value, making the redirect source immediately visible in response headers.

HTTP/1.1 301 Moved Permanently
Location: https://example.re/updated-path/
X-Redirect-By: Rank Math

Takeaway

The X-Redirect-By header names the application or plugin responsible for a redirect response. The header is most prevalent in the WordPress ecosystem, where plugins use the x_redirect_by filter hook to identify their redirects.

See also

• Location
• Redirects
• 301
• 302
• HTTP headers