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.
JavaScript Microtask & Promise Execution Order Debugging
A deep dive into debugging broken promise execution order and microtask queue race conditions in Node.js and browser environments.
Debugging TypeScript .d.ts Declaration File Errors
A practical guide to diagnosing and fixing errors in TypeScript declaration files, covering common pitfalls with third-party types, custom declarations, and compiler issues.
TypeScript strictNullChecks 'possibly undefined' Error: A Debugging Guide
Practical debugging guide for TypeScript's strictNullChecks 'Object is possibly undefined' errors. Covers real-world causes, quick diagnosis, and fixes beyond the obvious.
TypeScript Path Alias 'Cannot Find Module' Errors
A practical guide to diagnosing and fixing 'Cannot find module' errors when using TypeScript path aliases in tsconfig.json.
Debugging TypeScript Conditional Types: Infer Not Firing Correctly
A focused guide on why `infer` in conditional types produces unexpected `never` or wrong types, with concrete diagnostic steps and fixes.
JavaScript Generator Iterator Not Working: Debugging Silent Failures
A hands-on guide to debugging JavaScript generators that fail silently, produce unexpected values, or skip iterations. Covers advanced edge cases like premature return, error swallowing, and iterator protocol violations.
Long-form thinking on debugging habits, observability, and the systems around the bug.
The Art of the Minimal Reproducible Example: A Debugging Superpower
A minimal reproducible example (MRE) is more than just a snippet — it's a tool that isolates the bug, saves time, and gets you faster answers. Here's how to build one that works, with a real-world war story.
Retry Storms: When Retries Make a Cascading Failure Worse
Retries seem like a safety net, but in a distributed system under load they can turn a small hiccup into a full outage. Here's how retry storms form and what to do about them.
Caching Bugs Are the Worst: A Postmortem on Stale Data Disasters
A deep dive into the most insidious caching bugs, with real postmortems and practical patterns to avoid stale-data disasters.
Observability vs. Monitoring: Why Your On-Call Rotation Still Wakes You Up at 3 AM
Monitoring tells you something is broken. Observability lets you figure out why—without guessing, without SSH, without restarting the pod.
Debugging Flaky Tests for Good: A Systematic Approach to Root Cause Analysis
Flaky tests waste time and erode trust. Here's how to find and fix the actual root cause instead of just rerunning.
Idempotency Keys: The Safety Net Your Payment API Needs
How idempotency keys prevent double charges, lost refunds, and data corruption in payment APIs. With real-world examples and edge cases you haven't considered.