linear-webhooks-events

# Linear Webhooks & Events ## Overview Set up and handle Linear webhooks for real-time event processing. Linear sends HTTP POST requests for data changes on Issues, Comments, Issue Attachments, Documents, Emoji Reactions, Projects, Project Updates, Cycles, Labels, Users, and Issue SLAs. **Webhook headers:** - `Linear-Signature` — HMAC-SHA256 hex digest of the raw body - `Linear-Delivery` — Unique delivery ID for deduplication - `Linear-Event` — Event type (e.g., "Issue") - `Content-Type: application/json; charset=utf-8` **Payload body includes:** `action`, `type`, `data`, `url`, `actor`, `updatedFrom` (previous values on update), `createdAt`, `webhookTimestamp` (UNIX ms). ## Prerequisites - Linear workspace admin access (required for webhook creation) - Public HTTPS endpoint for webhook delivery - Webhook signing secret (generated in Linear Settings > API > Webhooks) ## Instructions ### Step 1: Build Webhook Receiver with Signature Verification ```typescript import express from "express"; import crypto from "crypto"; const app = express(); // CRITICAL: use raw body parser — JSON parsing destroys the original for signature verification app.post("/webhooks/linear", express.raw({ type: "*/*" }), (req, res) => { const signature = req.headers["linear-signature"] as string; const delivery = req.headers["linear-delivery"] as string; const eventType = req.headers["linear-event"] as string; const rawBody = req.body.toString(); // 1. Verify HMAC-SHA256 signature co...