What is Serverless?
Serverless computing lets you run code without managing servers. You upload functions, and the cloud provider handles scaling, patching, and availability. AWS Lambda, Vercel Functions, and Cloudflare Workers are popular options.
When Serverless Excels
- API Backends: Handle thousands of concurrent requests without provisioning servers.
- Webhooks & Event Processing: Process events from Stripe, Twilio, or message queues.
- Scheduled Tasks: Run cron jobs for reports, cleanup, or notifications.
- Prototypes: Launch MVPs in hours, not days.
When Serverless Falls Short
- Long-Running Tasks: Lambda has a 15-minute timeout. Video processing or large data migrations need containers.
- Stateful Applications: Serverless is stateless by design. Sessions and WebSocket connections require additional services.
- Cold Starts: First invocations can take 500ms-2s, which is unacceptable for latency-sensitive APIs.
- Vendor Lock-in: Migrating from Lambda to another platform requires significant code changes.
The Hybrid Approach
Most production systems use a hybrid: serverless for event-driven tasks and containers for core application logic. This gives you the best of both worlds.