headerbased

Headerbased, often written as header-based, refers to a design approach in which processing, routing, or decision-making is driven primarily by values found in HTTP headers. In this approach, header fields convey metadata such as authentication tokens, routing hints, content types, or user context, enabling components to act without relying on the request path or query parameters.

Common use cases include header-based routing and load balancing, where reverse proxies or load balancers direct requests to backends based on header values (for example, a specific X-Region or X-User header). It is also used for authentication and access control by transmitting API keys or bearer tokens in headers, as well as for content negotiation through Accept and Content-Type headers. Some deployments leverage headers for feature flagging, tracing, or telemetry to influence processing without altering URL structures.

Implementation is typically found in API gateways, reverse proxies, and load balancers. Popular platforms support header-based configurations, such as route matching or rule evaluation against header values. Examples include Nginx and Envoy-based proxies, and cloud load balancers and API gateways that offer header-based routing rules.

Advantages of headerbased include statelessness, flexible routing without changing URLs, and easier experimentation (for example, A/B testing) by shifting routing decisions into headers. Downsides can involve header spoofing or manipulation by clients, potential privacy concerns, and caching complications if headers vary frequently. Proper security practices—such as validating headers on trusted boundaries, using TLS, and avoiding sensitive data in headers—are important for reliable and secure deployments.

See also: HTTP headers, header-based routing, API gateway, reverse proxy, load balancer.