Choose Your Level
Pick the difficulty that matches where you are. You can come back and try a harder level later.
Fix a Bug in a Sample To-Do App
Diagnose and fix a state management bug in a React to-do app.
Memory Leak in an Event Listener
Diagnose and fix a React memory leak caused by un-garbage-collected DOM nodes.
Race Condition in Async Data Fetching
Fix a tricky race condition where stale network responses overwrite fresh data.
Production Bug Debugging & Root Cause Analysis (RCA)
Debugging production failures requires methodical troubleshooting skills. Tech leads look for developers who inspect error log stack traces, write Root Cause Analysis (RCA) post-mortems, reproduce complex edge cases in test environments, and deploy regression patches.
1. Production Incident Post-Mortem & RCA
Detailed RCA document analyzing incident timeline, root cause, impact, immediate fix, and preventive action items.
2. Isolated Regression Unit Test
Unit or integration test reproducing the exact failure edge-case before the bug fix is applied.
3. Bug Fix Patch & Deployment Verification
Code modification patch resolving the bug alongside deployment verification log.
Frequently Asked Questions (Debug & Fix)
What is a 5 Whys Root Cause Analysis?
The 5 Whys method iteratively asks 'Why did this happen?' five times to dig past surface symptoms to underlying process or technical failures.
Why is reproducing a bug in an isolated test the first step in fixing it?
Reproducing the bug in a automated test proves you understand the root cause and provides immediate automated verification when the fix works.
What should be included in a blameless post-mortem?
Incident timeline, technical root cause, business impact, short-term remediation, and long-term systemic preventive actions.
Explore Software Development Career Paths
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