How do I test Slack Block Kit blocks without deploying?

Use botlint-slack's `validate()`—offline checks for limits, types, errors. Instant, specific feedback.

What's the best way to unit test Slack Bolt handlers?

`createMockClient()` from botlint-slack. Pass to handlers, assert calls/payloads. No network needed.

Silent metadata drop to avoid crashes. Test with validation tools to catch it early—no live deploys.

Slack's API ghosts invalid blocks with 200 OKs, forcing devs into live deploys for every tweak. Here's the data-driven fix that's finally arriving.

Open Source Beat Apr 16, 2026 4 min read

Slack bot testing fails silently—200 OK on invalid blocks forces live deploys. 𝕏
botlint-slack delivers offline validation + mocks: sub-second units, no network. 𝕏
Two layers beat hacks: units daily, E2E on CI. Slack's delays handed win to OSS. 𝕏