Codync

The open-source Grok Bot alternative. Your coding agents, as teammates you can message.

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Free, open source, no paid tier. A ⭐ is how others find it.

macOS: Apple Silicon + Intel (DMG) · Windows: x64 installer · Linux: AppImage · All downloads

Codync turns the coding agents on your computer — Claude Code, Codex, Cursor, Pi, OpenCode, Grok Build, Gemini, Copilot and ~40 more — into persistent bots you delegate to from your iPhone, Mac, Windows PC, Linux desktop or any terminal, the way you'd message a colleague. Pick who, say what, put the phone away. You get a notification when a bot finishes or needs your approval.

Why bots? On a phone, "find the right working session, then pick an environment" is too slow. With bots you already know who to hand the intent to: open the chat, type, done.

Why Codync

• Free and open source. No subscription, no paid tier, Apache 2.0 licensed. It runs on your computer with the agents and accounts you already have.
• Bring any coding agent. Claude Code, Codex, Cursor, Gemini, Copilot, OpenCode, Pi, Grok Build and ~40 more — everything in the ACP registry. Installed agents are found automatically, the rest are fetched on first use, and every bot picks its own. Mix them freely: a Claude bot can ask a Codex bot for a review.
• Many bots, one team. Run as many bots as you like side by side, each with its own agent, project folder and approvals, all working at once. Put several in a group chat and they answer in turn, like a team channel; @name picks who replies. Start a thread on any message to branch off without cluttering the main chat.
• Built in Rust. codync-host is one small, fast Rust binary for macOS, Windows and Linux (static on Linux, runs on any distro) that drives every agent, keeps the transcripts and serves every client.
• One app per kind of device. Native SwiftUI on the iPhone, one desktop app for Mac, Windows and Linux (Electron), and a terminal UI for SSH.
• A Grok Bot, Muse and Dots alternative. Persistent named bots, group chats, reply threads, bots asking each other for help, approval cards, per-bot memory, remote screen, voice calls and "needs you / done" notifications — the same features, without being tied to one model or one subscription.
• Reach your computer from anywhere, free. The hosted Cloudflare relay is included at no cost: no Tailscale, no VPN, no port forwarding. Traffic is end-to-end encrypted between your phone and your computer, so the relay only forwards ciphertext. Same Wi-Fi or Tailscale? The phone connects directly instead.
• Every computer, one app. Sign in and your iPhone lists every computer on your account (Mac, Windows PC, Linux desktop, server or cloud VM); tap Connect, confirm a 6-digit code on that computer, and its bots show up next to the others. A new bot can live on any of them, and the Mac app reaches your SSH machines too. Each computer approves each device itself, so an account alone never unlocks a computer.
• Remote screen. See and control your computer from the iPhone over WebRTC (hardware H.264), and let bots use the screen themselves through the built-in computer tool.
• Voice calls. Talk to a bot hands-free from the iPhone and hear its replies read aloud.
• Private push. Notification text is sealed to your phone's key, so the push relay never sees what your bots said.

Platforms

The host (codync-host, Rust) runs on macOS, Windows and Linux; every client talks to it, so all your bots and chats are the same everywhere.

Looking for the former native Mac app (SwiftUI + AppKit)? Version 2.7.0 moved Mac and Linux to one Electron desktop app. The native implementation is preserved in Git history; see the changelog and source lookup commands and the archived AppKit chat implementation notes.

How it works

Remote Apple client ⇄ encrypted channel (direct or Cloudflare cloud/) ⇄ codync-host ⇄ ACP agent
Local / SSH client  ⇄ loopback HTTP + SSE                             ⇄ codync-host
Host notifications → APNs worker (relay/) → iPhone

• Bots have a name, a character avatar, standing instructions, an agent backend, a project folder and a permission policy. Each bot has a persistent main chat and optional reply threads; the agent sessions underneath are an implementation detail (resumed with session/load, restarted with New session).
• Group chats hold several bots and you. Each message starts a short room turn: the bots you @-mention (or everyone) reply one at a time, each in its own session, and can react to each other, up to 3 rounds. See group chats and threads.
• Bots can ask each other for help. Tell one “ask Reviewer to check these changes.” The built-in team MCP server lets it discover your other visible bots and wait for a reply. Requests appear in both chats; each recipient keeps its own agent, folder and approvals. Native subagents stay under the coding agent's control. See bot collaboration.
• The chat only shows what matters: your messages, each turn's final reply, approval cards and notices. Every tool call, diff, plan and thought is one tap away in Full conversation. While a bot works, its row shows what it's doing right now.
• Agents are detected automatically: the host hydrates PATH from your login shell (plus Homebrew, ~/.local/bin, nvm, bun, volta, asdf, mise, pnpm…), finds every harness you have installed, and prefers its native ACP mode. Anything else in the official ACP registry can be picked too — Codync fetches it on first use (npx, uvx or a checksummed binary).
• codync-host (Rust, macOS, Windows and Linux) runs on your computer. It speaks the Agent Client Protocol to each agent, keeps transcripts in SQLite, and serves the phone. Every change carries a global rev, so the phone reconnects with since: rev and never misses anything.
• Usage limits come from your local installs, with no extra login: Claude via claude -p /usage (a local command, no m