Slack App & Bot Patterns

Everything you need to build a real Slack app — not a hello-world bot. Covers signature verification (the right way, with raw-body and replay guards), slash commands with response_url for long jobs, interactive Block Kit modals and buttons, Events API with idempotency, multi-workspace OAuth distribution, rate-limit + 429 retry handling, and deployment templates for Vercel, Cloudflare Workers, and AWS Lambda. Also documents the gotchas that bite every Slack dev: the 3-second ack deadline, trigger_id expiry, mrkdwn vs Markdown, channel_not_found, ephemeral message limits, scope re-install, and Block Kit field length limits. Includes a distribution checklist for the Slack App Directory and a quick endpoint reference. Drop it into any agent that builds Slack integrations and skip the 4-hour learning curve.