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.
NextAuth Session Not Persisting: Debugging Silent Token Refresh Failures
A hands-on guide to debugging why NextAuth sessions silently vanish after page navigation, focusing on JWT callback, token refresh, and provider configuration.
Supabase Auth Not Working: Session, Redirect, and JWT Debugging
A hands-on debugging guide for Supabase auth failures—session drops, redirect loops, and JWT validation errors in production.
Passport.js Strategy Not Authenticating: A Diagnostic Walkthrough
Step-by-step guide to debug a Passport.js strategy that silently fails to authenticate, covering serialization, middleware order, and callback pitfalls.
bcrypt.compare() Always Returns False: A Field Guide
Debug why bcrypt.compare() always returns false. Covers salt rounds, encoding mismatches, and truncated hashes with real commands.
Vite Production Build Error: Debugging Crashes, Blank Screens, and Silent Failures
A concise guide to diagnosing and fixing Vite production build errors, including crashes, blank screens, and silent failures.
Vite HMR Not Working: Debugging Stale Modules and Silent Failures
A practical guide to debug Vite Hot Module Replacement when changes don't reflect, including common pitfalls like file watcher limits, dependency caching, and misconfigured optimizations.
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.