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.
18 playbooks · 509 guides · 96 articles · 13 linked practice labs ·skip to practice
Fast pattern recognition for the production failures engineers see most often.
18 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.
Null Pointer from Kotlin Platform Types in Java Interop
A guide to debugging NullPointerException from platform types when calling Java code from Kotlin. Covers root causes, diagnosis, and fixes.
Android ANR (Application Not Responding) Debugging: From Input Dispatch to Watchdog Timeouts
A field guide for Android engineers on diagnosing and fixing Application Not Responding (ANR) errors, covering input dispatch, broadcast receivers, and service timeouts.
Debugging Excessive Recomposition in Jetpack Compose
A deep dive into identifying and fixing unnecessary recompositions in Jetpack Compose, covering state hoisting, stable types, and common anti-patterns.
Swift Retain Cycles in Closures: How to Find and Fix Them
A guide to diagnosing, fixing, and preventing retain cycles caused by closures in Swift, with real-world debugging steps and a detailed incident story.
SwiftUI View Not Updating When State Changes: A Field Guide
Your SwiftUI view stays stuck even though @State or @Published values change. This guide covers the real reasons—wrong view identity, unnecessary equatable conformance, and publishers on background queues—and how to fix them.
Swift Actor Data Race Concurrency Debugging: Real-World Race Conditions in Actors
A practical guide to debugging data races in Swift actors, covering reentrancy, priority inversion, and actor-isolated state corruption with real crash logs and diagnostic steps.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Mocking External APIs in Tests: Why stubbing HTTP is harder than it looks
Stubbing HTTP calls seems easy until a subtle mismatch between your mock and the real API causes a production incident. Here's what I learned the hard way.
How I Diagnosed a 1-in-1000 Race Condition in Our CI Pipeline
A race condition that only appeared once every thousand CI runs took weeks to track down. Here's how we finally caught it, what tools helped, and what we changed to prevent similar bugs.
How Database Indexes Work: A Debugging Story
A practical guide to understanding database indexes through the lens of debugging a real production outage caused by a missing covering index.
Reading PostgreSQL EXPLAIN ANALYZE Output: A Practical Guide with Real Query Examples
EXPLAIN ANALYZE is the single most important tool for diagnosing slow queries. Here's how to read the output, spot common pitfalls, and fix them with real-world examples.
When caches lie: debugging stale data in distributed systems
Cache invalidation is often cited as one of the two hard problems in CS, but the daily reality is subtler: partial staleness, clock drift, and silent evictions. This post walks through real debugging techniques for stale data in Redis, Memcached, and CDN layers.
Debugging Cache Invalidation Failures: A Case Study with Redis and PostgreSQL
Cache invalidation sounds simple — write-through, TTLs, done. But in practice, silent failures hide in race conditions, connection pools, and stale read replicas. Here's a real debugging story with Redis and PostgreSQL that taught me how to find them.