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.
WebSocket Reconnect Storm & Thundering Herd Debugging
Diagnose and fix cascading WebSocket reconnection storms triggered by thundering herd patterns in distributed systems.
DNS Caching Stale Records: Why TTL Is Ignored and How to Fix It
A practical guide to debugging cases where DNS resolvers serve stale records past their TTL, covering common causes like resolver caches, stub resolvers, and low TTLs.
Debugging HTTP Keep-Alive Connection Reset by Peer
A practical guide to diagnosing and fixing 'connection reset by peer' errors on HTTP keep-alive connections, covering server, proxy, and network causes.
PostgreSQL Logical Replication Slot Lag: How to Diagnose and Fix WAL Buildup
A concise guide to diagnosing and resolving PostgreSQL logical replication slot lag, including WAL accumulation, consumer failures, and monitoring commands.
PostgreSQL TOAST Table Bloat: Diagnosis and Recovery
A practical guide to identifying, diagnosing, and fixing TOAST table bloat in PostgreSQL, including real commands and war stories.
MongoDB WriteConflict Transaction Retry: A Practical Debugging Guide
Step-by-step debugging guide for MongoDB WriteConflict errors in transactions, covering causes, diagnostics, and fixes.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Profiling SQL Queries: Finding and Fixing the Slow 5%
Profiling SQL queries is more than running EXPLAIN. This guide covers practical techniques to find the slowest queries, interpret execution plans, and fix them — with real examples from PostgreSQL and MySQL.
Debugging Character Encoding Problems: From Gibberish to Unicode
A practical guide to identifying and fixing character encoding problems, from broken UTF-8 to hidden BOM bytes, with real debugging examples.
Debugging Timezone Date Bugs: A Case Study in UTC vs. Local Time
A practical walkthrough of a timestamp bug that broke a billing system, with reproducible code and debugging tactics.
Floating Point Arithmetic Errors: A Debugging Postmortem
How a $0.0000000000000004 error silently corrupted a financial system, and the debugging techniques that caught it.
Why JSON.parse() Throws and How to Catch It: A Field Guide to Parsing Failures
JSON.parse() seems simple until it throws. Here's a practical guide to the most common — and most maddening — parsing failures I've encountered, with exact error messages and fixes.
Debugging Third-Party API Issues: A Systematic Approach
A practical guide to diagnosing and fixing third-party API integration problems, with real-world examples and a step-by-step debugging framework.