Traffic Forking: Send Matching Requests to Another Destination

Description

I’d like to request a feature that allows Proxyman to split or fork captured traffic and forward specific requests to a secondary endpoint. The idea is to listen to traffic as usual, but when certain requests match a defined pattern (e.g., URL, headers, or body contents), Proxyman would forward a copy of those requests to a user-defined collector endpoint for additional processing or inspection.

For example, I’d like to capture requests made by Claude Code, and forward those that match a pattern to my collector service. This would let me analyze the structure of the payload in real time without interrupting the original flow of traffic.

Why this feature/change is important?

This feature would expand Proxyman’s usefulness beyond debugging and inspection into traffic routing and collection.

• Advanced Analysis: Developers could forward a subset of traffic to custom collectors for logging, metrics, or ML analysis.
• Non-Intrusive: It enables inspection without modifying or blocking the original request.
• Flexibility: Pattern-based forwarding gives developers fine control (e.g., forward only API calls to specific hosts, endpoints, or with particular payload structures).
• Developer Tooling: This would make Proxyman more competitive with other proxy tools that offer scripting or extensibility.

In my case, I’d like to inspect and analyze AI tool requests (Claude Code) in a collector endpoint I’ve built. Having Proxyman forward matching traffic directly would save time and reduce the need for external tooling.

The issue names no files, tests, or entry points to inspect. Clarify the supported matching rules, collector endpoint behavior, protocols, failure handling, and acceptance criteria before locating the existing traffic-capture and forwarding architecture; done should demonstrate that matching requests are copied without interrupting the original flow.