Block launches Buzz, an open-source Slack rival for AI agents
Jack Dorsey’s Block has released Buzz, an open-source workplace app designed for human and AI collaboration that could appeal to European firms seeking to avoid US vendor lock-in.
Jack Dorsey’s Block has released Buzz, a free, open-source messaging platform built for teams of humans and AI agents. The app offers familiar workplace tools like channels, threads and voice, but treats autonomous software as colleagues rather than passive bots.
Unlike traditional chat tools, every AI agent on Buzz operates with its own cryptographic identity and defined permissions. They can post updates, review code and execute approved workflows alongside human workers. The platform is model-agnostic, meaning companies can plug in agents built on systems like Claude Code, Codex, or Block’s own goose.
The platform runs on Nostr, a decentralised protocol long backed by Dorsey. Block uses this to solve the problem of identity in multi-agent work, ensuring an agent's history and reputation are tied to a cryptographic keypair rather than a vendor’s API key. This makes the agent's identity portable across any compatible system.
Buzz ships under an Apache-2.0 licence, allowing companies to run their own self-hosted instances. “Every company is going to need a place where humans and agents work together,” said Bradley Axen, Block’s Head of AI Capabilities. “The question is whether that place is proprietary or open. We built Buzz because we believe it should be open.”
This open, self-hosted approach targets a specific pain point for European businesses. As companies integrate AI into daily operations, many are building agent infrastructure on proprietary platforms run by a handful of US tech giants. This creates heavy vendor dependency, fragmentation, and data sovereignty concerns. A self-hosted Buzz instance offers an alternative, keeping corporate data entirely within a company's control and off third-party servers.
Block is entering a crowded market dominated by Slack and Microsoft Teams, which are aggressively deploying their own AI features. The product is early, with its Git integration still nascent. Furthermore, granting autonomous software its own cryptographic identity and workplace permissions is a double-edged sword. It streamlines workflows, but it is exactly the kind of autonomy that safety researchers continue to warn about.
