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.
Logs, Traces, and the Lies They Tell: Debugging a Stuck Queue in Production
A single stuck queue brought down an entire checkout flow. Here's how we traced the failure across services, what the logs didn't say, and the tools that finally showed the truth.
Pair Debugging: How to Debug Together Without Killing Each Other
Pair debugging sounds great on paper. In practice, it's easy to step on each other's toes, go silent, or fight over the keyboard. Here's how to make it work.
Debugging with AI Tools: What Worked and What Didn't in Production
After a year of using GPT-4, Copilot, and Claude to hunt production bugs, here's what actually helped — and what sent me down dead ends.
How to Debug Legacy Code Without Losing Your Mind
A pragmatic approach to debugging code you didn't write, with techniques for tracing execution, isolating side effects, and making safe edits.
Debugging Feature Flag Rollouts: Tracing the Live-at-5 Incident
A misconfigured feature flag triggered a cascading failure in production. Here's how we traced the root cause and built a better debugging toolkit.
How to Ask for Debugging Help Without Wasting Everyone's Time
Asking for debugging help is a skill. Here's how to provide enough context, show your work, and frame the problem so others can actually help you.