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 'this' Being Undefined in JavaScript
A practical guide to diagnosing and fixing 'this' binding errors where this is undefined in JavaScript, covering async callbacks, class methods, and strict mode.
TypeScript Function Overload Resolution: Fixing 'No Matching Signature' Errors
A focused guide to resolving TypeScript's 'No matching signature' error during function overload resolution, covering advanced patterns and real-world debugging tactics.
JavaScript Regex Catastrophic Backtracking Debug Guide
Diagnose and fix catastrophic backtracking in JavaScript regular expressions. Real commands, specific patterns, and a real incident story.
Debugging JavaScript NaN Comparison: Why NaN === NaN is False
A practical guide to understanding why NaN comparisons always return false in JavaScript, with real debugging steps and fixes.
Why Optional Chaining Returns Unexpected Undefined
A debugging guide for when optional chaining (?.) unexpectedly returns undefined instead of the expected value or error.
TypeScript Partial/Omit/Pick Type Errors: When Utility Types Fail at Scale
Debugging type errors with Partial, Omit, and Pick in TypeScript — real causes, concrete fix patterns, and a war story from a production codebase.
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.