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.
1 playbook in Frontend & Web
Structured investigations for the failure modes engineers meet in real systems.
React setState Called but State Not Updating: Real Debugging Steps
React state not updating after setState? Pinpoint hidden causes—like stale closures, async timing, or skipped re-renders—using targeted debugging tactics.
React.memo Fails to Prevent Re-render: Deep Props, Functions, and Traps
Debug React.memo not working: identify why supposedly memoized components still re-render, including deep prop equality, unstable functions, and context pitfalls.
Diagnosing 404s from Next.js API Routes That Should Exist
When your Next.js API route responds with a 404 despite existing, dig past simple typos. This guide covers real fixes, pitfalls, and non-obvious causes.
Next.js Middleware Not Executing on Expected Routes
Investigate why your Next.js middleware isn't firing as expected. This guide goes beyond basics and addresses subtle config, routing, and deployment issues.
Environment Variable Undefined at Runtime in Next.js Projects
Why and how Next.js environment variables end up undefined during runtime, including hidden build pitfalls. Step-by-step debugging for real production issues.
Diagnosing ‘React Hook Called Conditionally’ in Function Components
A hands-on guide to resolving errors from calling React hooks inside conditional blocks. Covers root causes, real-world mistakes, and validation steps.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Debugging Network Issues with Chrome DevTools: Timing, Waterfalls, and Hidden Columns
A practical guide to diagnosing slow requests, stalled connections, and caching bugs using the Network tab's non-obvious features.
Finding Jank in React Apps with Chrome DevTools Performance Tab
A practical walkthrough of the Performance tab for diagnosing frame drops and long tasks in React apps, with a real debugging story.
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.