Coterm is an open-source fork of Mosaic/cmux that adds self-hosted real-time pair programming. Two developers can drive the same live Claude Code session, while the collaboration backend runs in their own Cloudflare account.

Hi Product Hunt! I'm Simon, the maker of Coterm. AI coding agents are great when you work alone, but pairing around them still feels broken. Screen sharing turns one developer into a passenger, while chat loses the shared terminal, browser, and agent context. I built Coterm so two developers can join the same live workspace and drive the same Claude Code or other terminal-agent session together. You can keep the browser beside the terminal, share previews, and stay in the same context throughout the session. A few principles mattered to me: - Native macOS app powered by libghostty - Works with any terminal-based coding agent - Collaboration is self-hosted in your own Cloudflare account - Free and open source under GPL-3.0 Coterm descends from the cmux/Mosaic codebase and keeps full attribution in the repository. This is an early public release, and I would especially value feedback on: 1. Does the pair-programming flow feel natural? 2. Is the self-host setup clear enough? 3. Which coding-agent workflow should we support next? Thanks for taking a look!

The self-hosted angle is genuinely useful for teams worried about code leaving their infra, and the dual-driver model sounds smooth in practice. One thing that would make adoption easier on our side is a simple TUI indicator showing who currently has control of the session and a quick hotkey to request or hand off driving, since right now I can imagine both devs accidentally typing at the same time and stepping on each other without realizing it.

Coterm

Self-hosted pair programming, built on Mosaic

Self-hosted pair programming, built on Mosaic