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.
Case-sensitive import fails on Linux: how to debug it
Your import works on macOS and Windows but fails on Linux with 'module not found'. The fix is a single character.
Database transaction rollback not working: how to debug it
Your code calls rollback but the data stays committed. The transaction was never really open, or it auto-committed before the failure.
Redis cache serving stale data: how to debug it
Your Redis cache returns old data after the source of truth updates. The cache key, TTL, or invalidation is wrong.
Timezone off by one day in JavaScript: how to debug it
Your date shows the wrong day because of a timezone offset. The date string, parser, or display format is silently shifting it.
Retry logic creating duplicate requests: how to debug it
Your retry logic fires a second request before the first one finishes. The server processes both. Now you have two charges, two emails, or two orders.
Webhook fires twice: how to debug duplicate webhook deliveries
Your webhook endpoint receives the same event twice. The provider retried because your endpoint did not acknowledge fast enough, or your handler is not idempotent.
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.