👀 Is there an existing feature request for this?

• I have searched the existing issues

🔖 Enhancement description

Add fine-grained port control for replay target resolution, specifically:

1. ssePort — A new top-level config field (test.ssePort) and CLI flag (--sse-port) that overrides the HTTP port for SSE (Server-Sent Events) test cases. SSE requests are detected via text/event-stream in the response Content-Type or request Accept header.

2. protocol section — An extensible, map-based protocol config under test.protocol that allows per-protocol port overrides:

   test:
     protocol:
       http:
         port: 8000
       sse:
         port: 8047
       grpc:
         port: 8034

   New protocols or new keys within a protocol can be added in the config file without code changes.

3. replaceWith.port mapping — A port-to-port mapping inside replaceWith (both global and per-test-set) that acts as the highest-priority port override:

   test:
     replaceWith:
       global:
         port:
           8033: 8043
       test-sets:
         sse:
           port:
             8033: 8043

Updated priority order (lowest → highest):

1. Recorded app_port
2. test.port / test.grpcPort / test.ssePort
3. test.protocol.<proto>.port
4. replaceWith URL (if replacement contains explicit port)
5. replaceWith.port mapping (highest, overrides everything)

🎤 Why should this be worked on?

Currently Keploy only supports a single port for all HTTP requests and a separate grpcPort for gRPC. When an application serves both regular HTTP and SSE endpoints on different ports, there is no way to route SSE test cases to a different port during replay.

Real-world use cases:

• Microservices with SSE: Apps that serve REST on one port and SSE (e.g. real-time notifications, AI streaming responses) on another.
• Protocol-aware routing: Different protocols may run on different ports in development vs production. The protocol config enables this without juggling replaceWith URL rules.
• Port migration during replay: When replaying against a different environment, the replaceWith.port mapping provides a clean way to remap ports without rewriting full URLs.

💻 Repository

keploy