Optimize API Performance with Background Workers

Your API is slow because it's doing too much before it responds. A user places an order. Your endpoint saves it, charges payment, sends an email, generates an invoice, updates inventory. Then it responds. That payment call? 5 to 25 seconds. Thousands of requests during a flash sale? Thousands of blocked threads. Provider goes down? Your entire API goes down. But the user only needs one answer: "Did you get my order?" That's it. Everything else can happen after. The fix is one architectural shift: → API saves the order to the database → Queues the heavy work for a background worker → Returns "received" in ~50ms The worker picks it up and handles the rest:   Charge payment   Send email   Generate invoice   Update inventory If something fails, it retries with exponential backoff. If all retries fail, the user gets notified AND the engineering team gets an alert with the full traceback. Nobody is left in the dark. Three things I learned building this in production: 1. Save to the database before queuing. If the worker crashes, the order still exists. The DB is your safety net. 2. Use Celery's on_failure() hook. Define it once in a custom base class. When retries run out, it automatically notifies users and alerts your team. No scattered try/except blocks. 3. Your API is a receptionist, not a worker. It takes the request, confirms receipt, and hands it off. The real work happens in the background. What's the slowest thing your API does before responding? ↓ Full blog post with architecture diagram and code in the comments #Python #SoftwareEngineering #SystemDesign #BackendDevelopment #Celery

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Here's the full blog post with the architecture diagram, code examples, and failure handling patterns:https://medium.com/p/95b27b1e5f0b?postPublishedType=initial

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