Slack Block Kit Builder

Design Block Kit payloads, validate the locally checkable structure, then use Slack's Block Kit Builder when exact rendering matters.

This skill was refreshed against Slack's official reference and changelog on 2026-07-31. Read latest Block Kit coverage before using newer blocks.

Workflow

1. Choose the surface: message, modal, or Home tab.
2. Read surface compatibility.
3. Choose blocks from block types.
4. Add controls using interactive components.
5. Apply layout rules.
6. Include stable block_id, action_id, and callback_id values where interactions require them.
7. Run the bundled validator.
8. Use Slack Block Kit Builder for visual and server-side confirmation.

Core Rules