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.
FastAPI Dependency Injection Fails: Missing `async def` and Scope Mismatches
A practical guide to debugging FastAPI dependency injection errors caused by missing async def, incorrect scope, or parameter mismatches.
Django Celery Task Not Executing: A Field Guide to Silent Failures
Diagnose why your Celery task won't run in Django — from broker misconfigurations to worker crashes. Commands, logs, and fixes included.
Debugging FastAPI 422 Validation Errors: Pydantic Model Mismatches
A systematic approach to diagnosing and fixing HTTP 422 validation errors in FastAPI, focusing on Pydantic model mismatches and request parsing issues.
FastAPI Background Task Not Running: Debugging Silent Failures
A practical debugging guide for when FastAPI background tasks silently fail to execute, covering lifespan events, async context, and server configuration.
Debugging FastAPI CORS Errors from Frontend Requests
A practical guide to diagnosing and fixing CORS errors when a frontend makes requests to a FastAPI backend.
Python Multiprocessing PicklingError: How to Debug
A practical guide to diagnosing and fixing PicklingError when using Python's multiprocessing module. Covers pickling scope issues, lambda closures, and dynamic classes.
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.