Coterm

Coterm is a native macOS workspace for two developers collaborating in one terminal, browser and coding-agent session. It is best suited to pairs who already work with command-line agents and can operate a self-hosted backend. The focused workflow is compelling at no cost, but its Mac-only desktop app and limited session restoration rule out some teams.

Overview

A live room lets two developers follow the same terminal, see the other participant and share previews while working together. Coterm does not provide screen sharing, so it is designed for shared development context rather than remote control of an entire desktop. That makes it more precise for terminal-centric pairing and less suitable when visual desktop access is the main requirement.

The Mac application runs without a Coterm-hosted account service. Its relay, control plane, presence and approval flow run in the users' own Cloudflare account. This arrangement keeps the collaboration service under the team's control, while making backend setup and maintenance part of the practical commitment.

Key features

Terminal and coding-agent pairing

The shared workflow supports Claude Code, Codex, OpenCode, Gemini CLI, Aider, Amp, Cursor Agent and other CLI agents. Pairs can therefore stay in one agent-assisted terminal session instead of switching to a separate code-review or interview tool. It is a strong fit for two-person agent workflows, but the product's stated pairing model is specifically two developers rather than a larger group.

Native terminal workspace

Coterm uses a Ghostty-based terminal with vertical tabs and a notification panel. A socket-based control API, plus a CLI, exposes programmatic commands through both interfaces. Configurable hooks cover Claude Code, Amp, Cursor, Gemini and Kiro CLI, giving automation-minded users ways to connect their existing tools.

Restore and data boundaries

After relaunch, Coterm restores layout and metadata, not arbitrary live process state. Unsupported applications reopen as ordinary terminals, so long-running work that depends on a process remaining alive needs its own recovery approach. The terms say user code, files and content stay off Coterm's servers during normal use. Crash diagnostics, operating-system and app versions, and anonymous usage patterns may be collected, while personal information is not sold for marketing.

The beta iOS companion attaches to a Mac's terminals. Terminal traffic goes directly between phone and Mac over the user's network; forwarded notification text can pass through Coterm servers and Apple's push service. That is useful for monitoring from a phone, with a narrower privacy boundary for notifications.

Pricing

There is no free trial because the product is free to use, and no paid tier or seat quota is given. The plan suits pairs wanting a zero-cost, open-source Mac workspace and willing to run collaboration infrastructure themselves. Teams wanting a vendor-managed service, broader desktop coverage or commercial plan guarantees should evaluate alternatives instead.

Platforms

The desktop app requires macOS 14.0 or later and runs on both Apple Silicon and Intel Macs. Installation is available through a DMG or Homebrew. An iOS companion is in beta, while API and self-hosted components support the wider workflow. There is no stated Windows or Linux desktop application, making Coterm a poor choice for mixed-OS pairs.

Who it's for

Choose Coterm for two developers who want to pair directly inside terminal and coding-agent sessions, especially when Cloudflare-based self-hosting is acceptable. It is less appropriate for larger collaboration groups, teams centered on full-desktop screen sharing, or anyone who needs live processes to survive a relaunch automatically.

Pros and cons

• Pros: Free, GPL-3.0-or-later software avoids subscription cost.
• Pros: Shared support for major CLI agents keeps pairing in one working session.
• Pros: Self-hosted relay, presence and approval flow give teams control of the collaboration backend.
• Pros: CLI and Unix-socket control suit scripted workflows.
• Cons: macOS 14 or later is required, excluding Windows and Linux desktop users.
• Cons: No screen sharing means it cannot replace whole-desktop remote collaboration.
• Cons: Relaunch restores layout and metadata but not arbitrary live process state.
• Cons: Self-hosting shifts operational responsibility to the user.

Alternatives

For a broader shortlist, see Pair Programming Software.

Drovio is the better pick for cross-platform screen sharing, with a free two-person tier and remote control capped at 30 minutes per day.

Choose Pop when browser-based meetings with unlimited hosting and no time limit during its beta fit better than terminal pairing.

Zed suits users seeking a cross-platform code editor with a free personal plan and 2,000 accepted edit predictions.

Pick Hopp for a self-hosted option or a $15 a month cloud plan.

Saros is another free, open-source collaboration choice.

CodeInterview is aimed at structured interviews, with two free interviews per month.

Duckly fits occasional web sessions, offering two simultaneous participants on its free tier.

Remote Collab is a free, open-source SublimeText collaboration plugin.

Verdict

Coterm is a strong choice for two Mac-based developers who want free, agent-aware terminal pairing and control of their own collaboration backend. Look elsewhere if you need Windows or Linux desktops, full screen sharing, larger groups or reliable preservation of running processes after relaunch.