redirectseither

redirectseither is a term used to describe a conditional redirection mechanism that sends an HTTP request to one of two target URIs based on evaluated criteria. Rather than specifying a single permanent or temporary redirect, redirectseither allows server-side logic to choose between two destinations when a request matches a given rule.

Typical parameters for a redirectseither implementation include the matching condition (such as URL pattern, header value, cookie, geographic location, or device type), the primary target, the secondary target, and the HTTP status code to return (commonly 302 for temporary or 301 for permanent). Implementations vary and can appear as built-in directives in web servers, as middleware in web frameworks, or as rules in content delivery networks and load balancers.

Common uses include simple A/B routing, mobile-versus-desktop redirection, regional routing for localized content, and failover to an alternate page. Benefits include compact configuration for binary routing decisions and integration with existing routing logic. Risks and limitations include potential for open redirect vulnerabilities if target URIs are not validated, adverse search engine effects if redirects are misused, and increased complexity for caching and analytics.

Alternatives and related concepts include general-purpose rewrite rules, conditional routing, feature-flag driven routing, and reverse proxy configurations. Best practices recommend explicit validation of targets, clear use of appropriate HTTP status codes, and documenting the routing logic to maintain predictable behavior.