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.
Queue consumer not processing messages: how to debug it
Messages pile up in the queue but your consumer does nothing. The consumer might be crashed, stuck, or silently discarding messages.
JWT token invalid after deployment: how to debug it
JWTs work locally and in staging, but after a production deploy every token is rejected. The secret, algorithm, or clock changed.
Node version mismatch in CI: how to debug it
Your code uses a feature from Node 20 but CI runs Node 18. Build fails with a syntax error or missing API. The fix is one line in the CI config.
npm install works locally but fails in CI: how to debug it
npm install completes on your machine but CI throws errors. The issue is usually a clean environment gap: missing native build tools, lockfile drift, or platform-specific binaries.
File upload works locally but fails in production: how to debug it
Your upload endpoint works with local files but returns errors in production. The filesystem, permissions, size limits, or storage backend is different.
API returns 500 only in production: how to debug it
Your API endpoint returns 200 locally but 500 in production. Some code path that never triggers in dev fires in the real environment.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Debugging CSS Layout Issues: A Systematic Approach to Fixing Broken Layouts
A practical, step-by-step system for diagnosing and fixing CSS layout bugs — from overflow and collapsing margins to flexbox and grid misbehavior. Includes real DevTools workflows and a war story from production.
Debugging Accessibility Violations: A Systematic Approach from Audit to Fix
A practical guide to identifying, triaging, and fixing accessibility violations in web applications, covering automated tools, manual testing techniques, and common pitfalls.
Find the Real Cause of a Slow Page: A Profiling Protocol for Engineers
A practical protocol for profiling web page performance — not a list of metrics, but a repeatable process for finding what actually slows down your users.
Tracking Down Memory Leaks in Browser JavaScript: A Practical Field Guide
Memory leaks in the browser are subtle and hard to reproduce. This guide covers practical techniques to detect, isolate, and fix them using Chrome DevTools, heap snapshots, and allocation timelines.
Why Your 60fps Animation Stutters: A Deep Dive Into the Browser Event Loop
The event loop isn't just about callbacks. It's about when and in what order the browser processes tasks, microtasks, and rendering. Here's what actually happens between frames.
Remote Debugging Mobile Devices at Scale: What Works and What Doesn't
Setting up remote debugging for iOS and Android devices involves more than just enabling Developer Mode. Here's what I've learned from debugging over 500 devices in production.