Jack Dorsey’s Block launches Buzz: Open-source Slack rival for humans and AI agents

Block co-founder Jack Dorsey launched a new AI workplace app called “Buzz” that is said to challenge Slack and GitHub. The platform is touted as a group chat app for workplaces where both team members and AI agents can participate in the same group conversations. This means employees could chat with colleagues while also interacting with AI assistants that can answer questions, write code, summarise discussions, complete tasks, or help with workflows.

Dorsey shared an X post announcing the new chat platform and said Buzz is “model-agnostic, decentralised, self-sovereign, and open source.” In a company blog post, Block highlighted that the most productive work “happens when humans and agents are in the same room, working on the same thing, with shared context. There was no one platform designed for that, so we built one.”

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What is Buzz?

According to Block, Buzz is a collaborative workspace platform built on the Nostr protocol. It consists of features like channels, threads, direct messages, voice, media sharing, code repositories, and automated workflows. From the user interface perspective, Buzz looks like any other team chat app, similar to Slack or Microsoft Teams.

However, its unique capability is built-in AI. Rather than working as AI assistants, Buzz agents hold their own identities with defined permissions, which lets them post, review code, run approved automations, and join conversations alongside human teammates.

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Bradley Axen, Head of AI Capabilities at Block, said, “Every company is going to need a place where humans and agents work together.” He argued that “The question is whether that place is proprietary or open. We built Buzz because we believe it should be open.”

How does Buzz work?

Buzz is built on Nostr, a decentralised communication protocol that uses cryptography to verify identities. This will allow each person and each AI agent to have its own unique cryptographic identity. Therefore, the identity is not tied to Buzz, Block, or any specific AI provider's API keys or account system.

As a result, AI agents could theoretically carry their identity, history, and reputation across any application built on the Nostr protocol, rather than being locked into a single platform.

Block says that Buzz is “model-agnostic”, which means teams can plug in agents built on Claude Code, Codex, Goose, or custom-built frameworks. Buzz also connects to databases, CRMs, codebases, and file systems. Buzz will offer organisations the option to either run their own instance for complete control over data and infrastructure or use Block's hosted version, which provides the same decentralised protocol benefits on a managed platform. 

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How does Buzz challenge Slack and GitHub?

Dorsey publicly acknowledged that Buzz will challenge Slack and GitHub, as it combines workplace communication and team collaboration with AI agents that can assist with tasks such as writing, reviewing, and testing code. 

These capabilities are supported by Nostr, a decentralised protocol, and will be available under the Apache 2.0 open-source licence, allowing developers to use, modify, and build on the software.

Block is expanding Buzz with Git integration, aiming for open-source communities to host software projects, discuss ideas, review code changes, and collaborate with AI agents that help build and test software. Eventually challenging GitHub's role as a hub for developers.