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 · 96 articles · 13 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.
Configuration Options Not Binding in .NET: How to Debug
A practical guide to debugging .NET configuration binding failures, covering real-world causes like casing mismatches, missing sections, and premature validation.
Elixir GenServer call timeout: How to find and fix the real cause
A hands-on guide for debugging Elixir GenServer call timeouts: from symptoms and root causes to specific fixes and verification steps, with a real incident walkthrough.
Phoenix LiveView assign not updating UI: Debugging Stale State
A practical guide to debugging Phoenix LiveView UI that doesn't update after an assign change. Covers socket diffs, Ecto schema reloads, and dead-end pitfalls.
Debugging Ecto N+1 Preload Queries in Elixir
Identify and fix N+1 query problems caused by Ecto preload misuse in Elixir/Phoenix applications.
Elixir Process Mailbox Overflow: How to Diagnose and Fix Unbounded Message Accumulation
Diagnose and fix Elixir process mailbox growth that causes memory pressure, latency spikes, and crashes. Covers OTP mailbox internals, redbug, recon, and practical fixes.
Kotlin Coroutine Not Cancelling: Debugging Stuck Jobs
A practical guide to debugging Kotlin coroutines that ignore cancellation, covering common pitfalls like blocking calls, uncooperative suspend functions, and improper scope management.
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.