X-Redirect

The HTTP X-Redirect response header is an unofficial header identifying the redirect configuration or deployment phase applied to a response.

Usage

The X-Redirect header surfaces internal routing or deployment metadata. Observed primarily on Microsoft Azure infrastructure, the header carries opaque strings like Production-Phase3 identifying which redirect rule set or deployment ring handled the request.

Azure and similar platforms use phased deployment models where traffic is gradually shifted between rings or stages. A value such as Production-Phase3 indicates the request was processed under the third phase of a production deployment rollout. The header allows tracing which configuration governed a redirect response without inspecting infrastructure dashboards.

The Location header remains the authoritative header for where a redirect sends the client. X-Redirect adds context about the rule set or routing stage responsible for issuing the redirect. This is useful for debugging misrouted requests or unexpected redirect behavior during staged deployments.

The header is not part of any HTTP specification. Its format and values are defined entirely by the serving infrastructure and carry meaning only within the deployment context.

Values

Values are opaque strings defined by the serving infrastructure. No standardized set of values exists. Observed formats include:

• Production-Phase3: a named deployment phase indicating the third ring of a production rollout on Azure
• Other values follow similar Environment-PhaseN patterns or take the form of internal stage names meaningful to the deployment team

Example

An Azure-hosted service responds to a redirect request and includes X-Redirect to identify the deployment phase matching the redirect rule. The Location header carries the destination URL.

HTTP/1.1 301 Moved Permanently
Location: https://www.example.re/new-path
X-Redirect: Production-Phase3

During active deployment rollouts, different traffic segments receive different phase values, allowing operators to confirm traffic is hitting the intended configuration stage.

X-Redirect: Production-Phase2
Location: https://www.example.re/

Takeaway

The X-Redirect header exposes internal deployment ring or redirect rule metadata on infrastructure using phased rollouts. The values are opaque and specific to the serving platform.

See also

• X-Redirect-By
• Location
• Redirects
• HTTP headers