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.
TLS Handshake Failure: Connection Reset Debugging Guide
A practical guide for diagnosing and fixing TLS handshake failures that manifest as connection resets, covering packet-level analysis, cipher mismatches, and server-side issues.
OpenTelemetry Metrics Not Exporting: A Field Guide
A direct, actionable guide for debugging OpenTelemetry metrics that fail to export. Covers collector configuration, SDK timing, and common silent failures.
Astro Component Hydration Not Working: Debugging Missing Client-Side Interactivity
A debugging guide for Astro components that fail to hydrate: symptoms, root causes, diagnosis steps, and fixes for missing client-side interactivity.
Debugging TypeScript Module Augmentation When It Silently Fails
A direct guide to diagnosing why your TypeScript module augmentation doesn't take effect, covering ambient module declarations, import side effects, and module resolution quirks.
Postgres Sequence Gaps in SERIAL ID: Why They Happen and How to Stop Panicking
A no-fluff guide to understanding why Postgres serial IDs have gaps, how to identify the cause, and when to actually worry.
CSS Modules Class Not Found: Why Your Imported Styles Object Returns Undefined
When a CSS Modules class import resolves to undefined at runtime, the root cause is almost always a misconfiguration in your build pipeline. This guide walks through the five real reasons it happens and how to fix each one.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Tracking Down a 200 MB Leak with Python Memory Profilers
A production API was silently leaking 200 MB of RAM every hour. Here's how memory profilers found the culprit—a forgotten NumPy array reference—and how you can apply the same techniques.
Reading CPU Flame Graphs: What the Hot Colors Actually Tell You
Flame graphs are everywhere, but most engineers read them wrong. Here's how to identify real bottlenecks, avoid common misinterpretations, and turn profile data into actionable fixes.
When Logs Lie: The Gaps Between What You Log and What Actually Happened
Logs are the first thing we reach for during an incident. But they can be misleading, incomplete, or outright wrong. Here's when to trust them and when not to.
Adding Observability to a 500K-Line Monolith Without a Rewrite
Adding structured logging, distributed tracing, and metrics to a legacy monolith without a full rewrite. Real code examples and a war story from a 500K-line codebase.
Distributed Tracing: Following a Single Request Across Microservices
Distributed tracing lets you follow a request as it hops across services. I'll show you how trace context propagates, why sampling matters, and how tracing helped us debug a 5-second latency spike in production.
Structured Logging in JSON: Fields, Schemas, and Pitfalls from Production
A practical guide to designing JSON log schemas that are queryable, consistent, and actually useful in production — with field recommendations and a war story.