Serverless at Scale: Lessons from Production

After running serverless workloads processing millions of requests per day, here are the hard-learned lessons.

Cold Starts Are Real

Despite what vendors claim, cold starts matter. Our strategies:

Provisioned concurrency for critical paths

Keep functions warm with scheduled pings

Optimize bundle size (tree shaking, minimal dependencies)

Serverless can get expensive fast. Monitor:

Function duration (optimize algorithms)

Memory allocation (right-size your functions)

Data transfer costs (VPC vs public endpoints)

**Idempotency**: Always design for retries

**Timeouts**: Set aggressive timeouts and handle gracefully

**Observability**: Structured logging and distributed tracing are essential

**Testing**: Local development with SAM/Serverless Framework

✅ Event-driven workloads

✅ Unpredictable traffic patterns

✅ Rapid prototyping

❌ Long-running processes

❌ Stateful applications