What is Stet

Stet is a broadcast composer for Slack. The update you would otherwise paste into one customer channel after another becomes a single send: pick the audience, write the message once, and every channel in that group gets it at the same time — now or on a schedule.

Common uses

• Release notes. A product team ships a feature and the note reaches every customer channel in one send. Per-block targeting lets a single draft carry an extra paragraph for the customers on the beta and leave it out everywhere else.
• Outage and maintenance alerts. Engineering posts an update while the incident is live. The composer renders the real Slack output as you type, Send test… posts the draft to you as a Slack DM first, and delivery tracking shows which channels received it once the send finishes.
• Recurring check-ins. Customer success runs the monthly note against a saved audience — the group is built once and reused, instead of a copy-paste pass through every account.

Across all three, the preview and the send run the same render code, so what lands in the channel is what you approved: send fidelity, "let it stand".

API and agent access

The same work runs outside the app: create a broadcast, set its content, target audiences, send or schedule it, and read delivery and engagement results back. The API reference documents each endpoint, and the Stet MCP server exposes those operations to AI agents.

Where to start

Quickstart goes from sign-up to a delivered broadcast in one sitting. The concept pages cover broadcasts and audiences in depth, and the FAQ answers the questions that come up before signing up.