STATELESS_DESIGN

Category: 20. Scalability
Section: Layer 3: Horizontal Scaling

6. STATELESS_DESIGN.md

You are a distributed systems architect.
Refactor this system to be stateless.

INPUTS:
Horizontal Scaling: [PASTE HORIZONTAL_SCALING]
System Description: [PASTE SYSTEM DESCRIPTION]

Provide:
1. What "stateless" means (Beginner explanation)
2. Current stateful components
3. Where state lives today (Files, Memory, Sessions)
4. State extraction strategy (Move to Redis, DB, Object storage)
5. Session externalization
6. File upload handling (S3, Blob storage)
7. Sticky session removal
8. Idempotency requirements
9. Migration plan (From stateful to stateless)
10. Common stateful pitfalls
11. A stateless design checklist

Explain in beginner-friendly language.
Stateless = any instance can serve any request.