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.
Redis Pub/Sub Subscriber Not Receiving Messages: A Debugging Guide
A practical guide to debugging Redis Pub/Sub when subscribers miss messages. Covers channel mismatches, client disconnections, and message ordering issues.
Redis Cluster Slot Migration Error: Diagnosis and Fix
A practical guide to diagnosing and resolving slot migration errors in Redis Cluster, covering common causes, verification steps, and real-world fixes.
Prisma Migration Drift: Schema Mismatch Between Generated Client and Database
When Prisma's generated client doesn't match the actual database schema, migrations fail or produce inconsistent results. This guide covers detection, root causes, and fixes for schema drift.
How to Find and Fix Prisma N+1 Queries with include and select
A practical guide to debugging N+1 query problems in Prisma when using include and select, with real commands and specific fixes.
TypeORM Relation Eager vs Lazy Loading Errors: Debugging Unexpected Query Behavior
When TypeORM relations load too many or too few rows, the culprit is often a mix of eager and lazy loading settings. This guide covers debugging unexpected query patterns and fixing silent performance issues.
Debugging GraphQL N+1 Queries with DataLoader Batching
When DataLoader batching fails, GraphQL resolvers generate cascading database queries that kill performance. This guide shows you how to find, fix, and verify the N+1 pattern with concrete tools.
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.