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.
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.
How to Read Error Messages: A Debugging Protocol
Most engineers skim error messages and miss the signal. Here's a repeatable protocol for extracting maximum information from stack traces, log lines, and crash dumps — with a real incident walkthrough.
When to Escalate a Bug: A Decision Framework for Junior and Mid-Level Engineers
A practical framework for junior and mid-level engineers to decide when to escalate a bug, with real-world examples and criteria beyond time spent.
Debugging vs. Firefighting: Why Treating Production Incidents as Debugging Sessions Fails
When production goes down, your brain wants to debug. That instinct costs you hours. Here's why firefighting requires a fundamentally different approach, and the specific process I use to switch modes.
Writing an Incident Runbook That Actually Gets Used in Production
A runbook isn't a document—it's a tool. Here's how to write one that reduces MTTR and doesn't embarrass you during the next PagerDuty alert.
Debugging a production incident with your boss on Slack: staying rational when everything is on fire
A personal account of debugging a cascading Redis failure while the VP of Engineering watched, and the mental models that kept the fix from turning into a rollback.
Reading Distributed Traces to Find Latency: A Field Guide
Tracing tools generate a firehose of data. Here's how to filter the signal from the noise and actually find the root cause of high latency.