Interoperability between js-libp2p and py-libp2p focused on ping protocol

Description

This issue tracks a cross-language interoperability test between py-libp2p and js-libp2p using the /ipfs/ping/1.0.0 protocol. The goal is to verify that a Python libp2p node can connect to a JavaScript libp2p node over TCP/WebSockets, negotiate the ping protocol, and successfully exchange a 32-byte payload.

This serves as a foundational test for validating protocol compliance, stream handling, and transport compatibility between the two implementations.

Motivation

libp2p is designed to be a modular, cross-platform networking stack that works across programming languages and runtimes. However, real-world interoperability between implementations (e.g., JavaScript and Python) requires active validation and testing.

This project aims to:

• Ensure compatibility between py-libp2p and js-libp2p on the protocol, transport, and stream levels.
• Provide a minimal working example to demonstrate cross-language communication using a well-defined protocol (/ipfs/ping/1.0.0).
• Lay the groundwork for broader protocol support (e.g., identify, pubsub, DHT) and more advanced scenarios like NAT traversal and QUIC/WebRTC transports.
• Support the libp2p community with a reproducible test suite that helps debug and verify cross-stack behavior.

Current Implementation

• The py-libp2p repository is under active development and includes support for:

  • Basic host and peer identity setup
  • TCP transport (partial WebSocket support may be experimental or missing)
  • Stream multiplexing using mplex
  • Protocol negotiation via multistream-select
  • Preliminary /ipfs/ping/1.0.0 protocol logic (may require additional integration)

• The js-libp2p stack is mature and fully supports:

  • Multiple transports: TCP, WebSockets, WebRTC
  • Stream multiplexers: mplex, yamux
  • Protocol negotiation and stream handlers
  • A built-in /ipfs/ping/1.0.0 responder

Currently, there is no integrated setup or test that connects a py-libp2p node with a js-libp2p node for pinging. Each stack operates in isolation, and interoperability is unverified.

Are you planning to do it yourself in a pull request ?

Maybe

Start by reviewing the py-libp2p host and peer identity setup, TCP/WebSocket transport support, mplex stream multiplexing, multistream-select negotiation, and preliminary ping implementation described in the issue. Define a reproducible integration test with js-libp2p that connects the nodes and exchanges the 32-byte /ipfs/ping/1.0.0 payload over a supported transport.