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.
Debugging Node.js Cluster Module Worker Crashes
A hands-on guide to diagnosing and fixing worker crashes in Node.js cluster mode, covering uncaught exceptions, memory leaks, and IPC failures.
Debugging TypeScript Generic Type Constraint Errors
A practical guide to diagnosing and fixing TypeScript errors when generic type parameters violate their constraints, with real-world debugging strategies and a war story.
Mapped Types Returning 'never' or 'unknown' — What Your IDE Won't Tell You
A field guide for when mapped types silently collapse to 'never' or 'unknown', covering conditional checks, key remapping, and distributive conditional types.
JavaScript Closure Stale Variable Inside Loop
A debugging guide for the classic JavaScript closure-in-loop bug where callbacks capture the final value of a loop variable instead of each iteration's value.
TypeScript Discriminated Union Type Narrowing Not Working
A practical debugging guide for when TypeScript's discriminated union type narrowing fails due to common pitfalls like excess property checks, optional discriminants, and type assertions.
Debugging Prototype Chain Inheritance Bugs in JavaScript
A guide to diagnosing and fixing subtle bugs caused by shared state and unintended property shadowing in JavaScript prototype chains.
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.