Buglyst Blog
Learn to debug under pressure.
Playbooks for fast pattern recognition, guides for the full investigation, and articles for the engineering judgment around the edges.
17 playbooks · 509 guides · 95 articles · 12 linked practice labs ·skip to practice
Fast pattern recognition for the production failures engineers see most often.
17 playbooks
Debugging Env Var Issues
A concise checklist for incidents where local works but CI, staging, or production changes behavior.
Debugging Cache Stampedes
How to recognize and contain request spikes when cached data expires.
Debugging CORS Origin Bugs
A practical way to inspect origin parsing, credentials, and header behavior.
Debugging Retry Bugs
Retry issues often hide the first failure and create duplicate work.
Debugging Timezone Bugs
Time bugs usually live at day boundaries, DST changes, and unit conversions.
Debugging Pagination Bugs
Pagination bugs hide in boundary math, cursor reuse, and new records arriving between pages.
Structured investigations for the failure modes engineers meet in real systems.
React setState Called but State Not Updating: Real Debugging Steps
React state not updating after setState? Pinpoint hidden causes—like stale closures, async timing, or skipped re-renders—using targeted debugging tactics.
React.memo Fails to Prevent Re-render: Deep Props, Functions, and Traps
Debug React.memo not working: identify why supposedly memoized components still re-render, including deep prop equality, unstable functions, and context pitfalls.
Diagnosing 404s from Next.js API Routes That Should Exist
When your Next.js API route responds with a 404 despite existing, dig past simple typos. This guide covers real fixes, pitfalls, and non-obvious causes.
Next.js Middleware Not Executing on Expected Routes
Investigate why your Next.js middleware isn't firing as expected. This guide goes beyond basics and addresses subtle config, routing, and deployment issues.
Environment Variable Undefined at Runtime in Next.js Projects
Why and how Next.js environment variables end up undefined during runtime, including hidden build pitfalls. Step-by-step debugging for real production issues.
Diagnosing ‘React Hook Called Conditionally’ in Function Components
A hands-on guide to resolving errors from calling React hooks inside conditional blocks. Covers root causes, real-world mistakes, and validation steps.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Logs, Traces, and the Lies They Tell: Debugging a Stuck Queue in Production
A single stuck queue brought down an entire checkout flow. Here's how we traced the failure across services, what the logs didn't say, and the tools that finally showed the truth.
Pair Debugging: How to Debug Together Without Killing Each Other
Pair debugging sounds great on paper. In practice, it's easy to step on each other's toes, go silent, or fight over the keyboard. Here's how to make it work.
Debugging with AI Tools: What Worked and What Didn't in Production
After a year of using GPT-4, Copilot, and Claude to hunt production bugs, here's what actually helped — and what sent me down dead ends.
How to Debug Legacy Code Without Losing Your Mind
A pragmatic approach to debugging code you didn't write, with techniques for tracing execution, isolating side effects, and making safe edits.
Debugging Feature Flag Rollouts: Tracing the Live-at-5 Incident
A misconfigured feature flag triggered a cascading failure in production. Here's how we traced the root cause and built a better debugging toolkit.
How to Ask for Debugging Help Without Wasting Everyone's Time
Asking for debugging help is a skill. Here's how to provide enough context, show your work, and frame the problem so others can actually help you.