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.
Flaky tests in CI: how to debug and fix intermittent test failures
A test passes nine times out of ten but randomly fails in CI with no code changes. Flaky tests destroy trust in the test suite — here is how to find and fix them.
Stale cache key bug: how to debug cache key collisions
Your cache returns data belonging to a different user, tenant, or request. The cache key is not unique enough — it is missing a dimension.
Distributed lock not releasing: how to debug stuck locks
Your distributed lock is acquired but never released. The lock holder crashed, the TTL expired but the key lingers, or the unlock logic has a bug.
Idempotency key not preventing duplicate payment: how to debug it
Your payment API accepts an idempotency key but still processes the same charge twice. The key is not being checked, stored, or matched correctly.
Slow API response: how to debug latency issues
An API endpoint that used to return in 50ms now takes 3 seconds. Find the bottleneck before your users notice.
N+1 query slowing down your API: how to find and fix it
Your API makes one query to get a list, then one more query for every item in the list. That is the N+1 pattern — it turns 1 query into 101 and kills performance.
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.