toxy
Hackable HTTP proxy for resiliency testing
...Its core model uses poisons to alter traffic and rules to decide when those alterations should apply. Tests can inject latency, limit bandwidth, return errors, manipulate payloads, or combine several adverse conditions. Rules can filter traffic by route, headers, query values, methods, bodies, and other request properties. A hierarchical middleware architecture makes the proxy extensible with custom behaviors and reusable modules. The repository was archived in 2023, so it is primarily useful as a reference or for legacy testing setups.