PacketProxy

The tool functions as a local proxy that can capture, inspect, and modify traffic for any TCP or UDP based protocol, not only HTTP/1.x, HTTP 2, or HTTPS. It records each request and response, stores them in a history view, and provides filtering and search capabilities. Users can edit intercepted packets before forwarding them, replay or resend them, and compare differences between two messages. Built‑in encoders and decoders support a range of protocols such as WebSocket, MQTT, gRPC, Protocol Buffers, XMPP over TLS, MessagePack, CBOR, and Amazon Lex V2, and developers can add extensions for additional formats.

For application testing and security analysis, the proxy can send multiple packets concurrently to probe race conditions, replace server certificates with self‑signed ones, and run a configurable DNS server to route client traffic transparently. Project data and history are saved in an SQLite3 file, and the software runs on Windows, macOS, and Linux.

Installation is provided via platform‑specific installers or Homebrew on macOS, and the source code is released under the Apache License 2.0, allowing developers to extend its protocol support or UI features.