Shopify's webhook delivery timeout is 5 seconds. After 19 consecutive failures, Shopify removes the subscription entirely. Your app silently stops working for every affected merchant. Synchronous webhook handlers cause this. Async architecture prevents it. Here are the five patterns every Shopify developer needs in production. The 50ms Rule: What Belongs in the Webhook Handler Everything in your webhook handler that isn't HMAC validation and queue enqueue is a liability. js // ✅ Async webhook handler — returns 200 in under 50ms app . post ( ' /webhooks ' , express . raw ({ type : ' */* ' }), async ( req , res ) => { const hmac = req . headers [ ' x-shopify-hmac-sha256 ' ]; const topic = req . headers [ ' x-shopify-topic ' ]; const shop = req . headers [ ' x-shopify-shop-domain ' ]; const webhook = req . headers [ ' x-shopify-webhook-id ' ]; if ( ! verifyShopifyHmac ( req . body , hmac )) { return res . status ( 401 ). send ( ' Unauthorized ' ); } await ingestionQueue .…