Production Debugging Skill

Use Case: Investigating production issues, reproducing bugs from ticket information, and planning test cases.

Core Debugging Workflow

Phase 1: Understand & Reproduce

1. Intake: Gather error logs, user reports, and environment details (Browser, OS, Staging/Prod).
2. Reproduce: Replicate the exact conditions. Write failing test cases to prove the bug exists before touching any application code.
   • If Frontend: Look for race conditions in React hooks, stale closures, missing keys, or CORS.
   • If Backend: Look for N+1 queries, missing indexes, race conditions, or null reference errors.

Phase 2: Root Cause Analysis (5 Whys)

Do not just patch the error. Determine why it happened.

• Why did the variable evaluate to null?
• Why did the database allow a null value?
• Why was validation missing?