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.
NumPy Broadcasting Shape Mismatch: A Field Guide to Silent Failures and Runtime Errors
Diagnose and fix NumPy broadcasting shape mismatches with concrete steps, error patterns, and a real incident walkthrough.
SQLAlchemy N+1 Queries: Diagnosing Lazy Loading Performance Disasters
How to detect, diagnose, and fix the N+1 query problem in SQLAlchemy caused by lazy loading. Includes concrete commands, SQLAlchemy event hooks, and realistic war stories.
Pandas dtype Unexpected Conversion: A Debugging Guide
When pandas silently changes dtypes from int to float, object to category, or datetime to object, debugging requires understanding pandas' internal type inference and nullable integer arrays. This guide covers real-world causes and fixes.
Debugging Python Datetime Timezone-Awareness and Offset Errors
A concise guide to diagnosing and fixing Python datetime offset and timezone-awareness bugs, with real-world examples and concrete commands.
Celery Beat Periodic Task Not Running: A Field Guide
A production-tested guide to diagnosing why your Celery Beat periodic tasks silently fail to execute, covering scheduler locks, timezone mismatches, and worker routing.
Python Virtual Environment Package Not Found: Debugging Guide
A practical guide to debugging 'module not found' errors inside Python virtual environments, covering PATH issues, activation traps, and pip installation nuances.
Long-form thinking on debugging habits, observability, and the systems around the bug.
How to Debug a Regression: A Practical Walkthrough
A practical, step-by-step guide to finding and fixing regression bugs, with real-world examples and concrete commands you can run today.
The Cost of Not Reproducing Bugs: Why Local Debugging Saves Hours
Skipping local reproduction leads to wasted hours, broken deploys, and frustrated teams. Here's why it's non-negotiable and how to do it right.
Debugging an Unfamiliar Codebase: A Systematic Approach
A repeatable process for debugging code you didn't write — with specific techniques, tooling choices, and a war story from a production outage at 2 AM.
5 Questions to Ask Yourself Before Filing a Bug Report
A senior engineer's pre-flight checklist for bug reports — forged in the fire of a production incident that turned a 5-minute fix into a 3-hour hunt.
Binary Search for Bugs: Cutting Down Bisection Time with git bisect run
Automating git bisect with a script turns days of manual hunting into minutes. Here's how to build a reliable bisection harness for your codebase.
Reading a Call Stack: What Each Frame Actually Tells You
A call stack shows you the path your code took to crash. But most developers only look at the top frame. Here’s how to read the whole thing — including async traces, native frames, and minified code.