Slack Block Kit Builder

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

Read latest Block Kit coverage before using newer blocks or fields.

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, checking both their parent block and surface.
5. If requested controls conflict with the surface, list the conflicts and choose a supported surface or split the flow before emitting JSON.
6. Apply layout rules.
7. Include stable action_id and callback_id values where interactions require them; use unique block_id values for each payload iteration.
8. Run the bundled validator and fix every error.
9. Use Slack Block Kit Builder for visual confirmation, then confirm server acceptance through the target Slack API method in a test workspace.

Core Rules