If you want off Slack or Discord and onto something you actually control, two very different tools showed up in our catalog this year. Both are free to run, both keep your conversations off someone else's cloud by default, and both are aimed at technical teams — but they solve that problem in almost opposite ways.
Chatto: a whole chat server in one file
Chatto is a Slack/Discord-style team chat app you run yourself, and the whole thing ships as a single ~50MB binary with zero external dependencies. There's no separate database to set up for a basic install, it encrypts data at rest with crypto shredding, and voice/video/screen share are built in via LiveKit.
Pricing: self-hosted deployment is free. A managed "Chatto Cloud" offering is entering public beta, but pricing for it hasn't been published yet.
Who it's for: teams and communities who want the familiar Slack/Discord experience — channels, voice, screen share — but with full data ownership and minimal ops overhead to stand it up.
Limits: it's built by a solo developer rather than a company, so support guarantees are unclear, and the open-source license status isn't explicit on the homepage. There's also no public GitHub star count to gauge how big the community actually is.
Buzz: chat where AI agents are teammates, not bots
Buzz is a free, open-source group chat built by Block (Jack Dorsey's company) with a different premise entirely: AI agents aren't bolted-on bots answering slash commands, they're participants with their own identity, permissions and a visible history of what they did, sitting in the same channel as humans. Git repositories are integrated directly into the chat space, and it runs on Nostr, a decentralized protocol, rather than a company-owned server.
Pricing: completely free and open source (Apache 2.0). Desktop apps exist for macOS, Windows and Linux; there's no mobile app yet.
Who it's for: engineering teams who already run AI coding agents and want them working visibly alongside humans in the same space, with git context built in — not a general replacement for Slack in a non-technical org.
Limits: no mobile app at launch, it's a very recent product (July 2026) with an ecosystem still forming, and being decentralized via Nostr means a different adoption curve than a conventional SaaS chat tool — there's no single company you're signing a contract with.
Side by side
| Chatto | Buzz | |
|---|---|---|
| Core idea | Slack/Discord clone, self-hosted, one binary | Chat where AI agents are first-class teammates |
| Architecture | Single server you host (or upcoming managed cloud) | Decentralized via Nostr protocol |
| Pricing | Free self-hosted; Cloud pricing TBA | Free, Apache 2.0 open source |
| Voice/video | Built in (LiveKit) | Not a focus |
| Git integration | No | Yes, repos live in the chat space |
| Platforms | Self-hosted server + clients | macOS, Windows, Linux desktop (no mobile yet) |
| Backing | Solo developer | Block (Jack Dorsey's company) |
Which one to pick
Pick Chatto if you want a straightforward, self-hosted Slack/Discord replacement — channels, voice, screen share, encryption — without needing to think about AI agents or decentralized protocols. It's the closer like-for-like swap.
Pick Buzz if your team already runs AI coding agents day to day and you want them visible in the same chat as your humans, with git repos and permissions attached to their identity rather than treated as a chatbot add-on. Accept that it's early, desktop-only for now, and built on infrastructure (Nostr) you don't fully control.
Neither has the maturity of Slack itself — Chatto is a one-person project and Buzz only shipped in July 2026 — so if uptime guarantees and enterprise support matter more than data ownership or agent-native design, both are still worth watching rather than betting the company on today.