Buzz folds team chat, Git hosting, search, and named AI agents onto one Apache-2.0 relay you run yourself, against the roughly $36 per user per month a team already pays for Slack Business+ and GitHub Enterprise seats.
A 40-person product team on Slack Business+ and GitHub Enterprise is paying somewhere around $36 per person per month for the privilege of keeping the conversation in one tool and the code in another. Call it $1,440 a month, a little over $17,000 a year, and what it buys you is the daily ritual of copying an answer out of one window and pasting it into a different one. Block just open-sourced the thing that collapses both onto a single server you own, and it bothered with the part everybody else has skipped: your AI agents get names and cryptographic signatures instead of being a browser tab somebody pastes out of.
The prices are on the vendors' own pages. Slack lists Business+ at $15 per user per month on annual billing, $18 if you pay monthly. GitHub lists Enterprise at $21 per user per month, and that figure is the introductory rate for the first year. Add a project tracker and a search layer on top and the real number is higher than $36.
What it does. Buzz is Apache 2.0, it picked up roughly 6,400 stars in the past week, and it is currently sitting in the top ten of GitHub's weekly trending list at about 24,000 total. Block's engineering team published the reasoning on July 21, and the diagnosis is sharper than the usual launch post. Giving everybody an AI agent made individuals faster and teams worse, because the org ended up with everyone "alone with an agent in a little harness window, copying its output into Slack." Humans became the integration layer between the agents.
Buzz runs as a relay built on Nostr, an open protocol for signed messages. The consequence that matters is architectural: chat messages, code reviews, workflow runs, and Git events are all the same kind of thing, signed events in one log. So a feature branch can become a room. So search covers a conversation, a patch, and a failed automation run in one query, instead of three tools with three answers.
Then there is agent identity, which is the piece nobody selling you seats has an answer for. Every agent in Buzz gets its own key, signed by the human who authorized it. The agent posts as itself and carries your signature on its credential. That turns "who approved the thing that opened this pull request" from a Slack screenshot into an audit trail. Git hosting is built the same way, with repositories stored as immutable content-addressed packfiles and mutable manifest pointers, sitting on object storage rather than a filesystem, so concurrent writes work at machine speed instead of fighting over locks. That is a design decision that only makes sense if you assume the thing writing to your repo is forty agents rather than four people. Block clearly assumes that.
Who it is for. This is for an engineering-led organization where agents already write a meaningful share of the code and the coordination overhead has become something people complain about out loud. It is also for whoever is going to get asked, this quarter, to produce an accounting of which agents touched production and on whose authority. There are pre-built desktop packages for macOS, Linux, and Windows, and a Railway one-click deploy for the relay, so standing one up is an afternoon rather than a project. It is not a marketing team's tool. If your engineers live in GitHub and your revenue team lives in Slack, Buzz plausibly replaces one of those, and half a migration is worse than no migration.
The honest caveat. This is pre-1.0 software and it is not pretending otherwise. The latest tag is Buzz Desktop v0.5.5 from August 5, and releases are landing every one to three days. That cadence is a sign of life and also a warning: what you deploy this week is not what you will be running next month. There are close to 900 open issues. The project's own landing page invites you to test the early stages with them, which is the right amount of honesty and also a real statement about readiness.
Self-hosting is not free either, and the free-versus-$36 framing hides where the money actually goes. Say yes to this and you become the operator of both your company's chat and your company's code host, which means uptime, backups, restores you have actually tested, and somebody's phone ringing. Part of that $36 buys enforced single sign-on, retention policies, discovery for legal, and a vendor to escalate to when search dies mid-incident. Buzz does not have those yet. Building on Nostr also means the integration surface you quietly depend on, the ticket-system hook, the alerting bridge, the compliance archiver, has not been written for it.
The bet Block is making is not that self-hosting is cheaper. It is that per-seat pricing falls apart the moment half your workforce does not have a credit card or a bathroom break. Nobody has decided yet what a Slack seat costs for something that runs four hundred sessions a day, and the vendors will answer that question in their own favor when they get around to it. Block just made sure there is a second answer sitting on the table when they do.