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.
The Debugging Mindset: A Systematic Method for Finding Root Causes
A repeatable, hypothesis-driven approach to debugging that works for intermittent failures, performance regressions, and production incidents.
Analyzing a Core Dump: What to Do When Your Process Goes Silent
A core dump is your process's last scream. Here's how to make it talk.
Timeouts Every Engineer Gets Wrong (and How to Fix Them)
Most timeout bugs aren't logic errors — they're configuration failures. Here's how to stop treating timeouts as magic numbers and start engineering them deliberately.
Backpressure in Streaming Systems: When Your Pipeline Fights Back
Backpressure is the system's way of saying 'slow down.' Ignore it and you get OOM crashes, silent data loss, or cascading failures. Here's how to design for it.
Finding Memory Leaks Step by Step: A Systematic Approach
Memory leaks are the silent killers of long-running services. Here's a repeatable process to hunt them down, from heap dumps to production monitoring.