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.
Diagnosing Node.js Event Loop Lag and High Latency in Production
An advanced guide to investigating and resolving unexpected event loop lag and high request latency in live Node.js applications.
Express Middleware Not Executing in Order: A Debugging Guide
Diagnose and fix Express middleware that executes out of order or skips entirely. Covers route ordering, next() misuse, and async pitfalls.
Node.js ESM/CommonJS Interop: require() of ES Module Fails
A focused guide on diagnosing and fixing the 'require() of ES Module' error when mixing module systems in Node.js.
Debugging Node.js Stream Backpressure: When HighWaterMark Betrays You
A practical guide to diagnosing and fixing backpressure failures in Node.js streams, covering highWaterMark tuning, drain events, and memory pressure.
Fastify Plugin Not Registered: Debugging the 'Missing Plugin' Error
A direct guide to debugging Fastify's 'plugin not registered' error, covering encapsulation, async registration, and dependency ordering.
Node.js Graceful Shutdown Not Completing: Debugging Dirty Handles and Stuck Timers
A direct, actionable guide for when process.exit() hangs or SIGTERM is ignored because of unclosed handles, active timers, or persistent connections.
Long-form thinking on debugging habits, observability, and the systems around the bug.
How to Debug a Regression: A Practical Walkthrough
A practical, step-by-step guide to finding and fixing regression bugs, with real-world examples and concrete commands you can run today.
The Cost of Not Reproducing Bugs: Why Local Debugging Saves Hours
Skipping local reproduction leads to wasted hours, broken deploys, and frustrated teams. Here's why it's non-negotiable and how to do it right.
Debugging an Unfamiliar Codebase: A Systematic Approach
A repeatable process for debugging code you didn't write — with specific techniques, tooling choices, and a war story from a production outage at 2 AM.
5 Questions to Ask Yourself Before Filing a Bug Report
A senior engineer's pre-flight checklist for bug reports — forged in the fire of a production incident that turned a 5-minute fix into a 3-hour hunt.
Binary Search for Bugs: Cutting Down Bisection Time with git bisect run
Automating git bisect with a script turns days of manual hunting into minutes. Here's how to build a reliable bisection harness for your codebase.
Reading a Call Stack: What Each Frame Actually Tells You
A call stack shows you the path your code took to crash. But most developers only look at the top frame. Here’s how to read the whole thing — including async traces, native frames, and minified code.