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.
HTTP Connection Timeout: Debugging Network Stalls and Misconfigured Timeouts
A practical guide to diagnosing HTTP connection timeouts caused by network latency, firewall drops, TCP backlog exhaustion, and misconfigured timeout stack.
OAuth2 PKCE Code Challenge Verification Failed
This guide covers diagnosing and fixing PKCE code challenge verification failures in OAuth2 flows, including S256 hash mismatches and incorrect code verifier handling.
Debugging OAuth2 Authorization Code Flow Errors
A tactical guide to diagnosing failures in the OAuth2 authorization code flow, covering redirect URI mismatches, state validation, token endpoint issues, and common provider-specific pitfalls.
Debugging HTTP 429 Too Many Requests – API Rate Limit Guide
A hands-on guide to diagnosing, mitigating, and preventing HTTP 429 rate limit errors with specific tools and patterns.
WebSocket Connection Closing Unexpectedly: A Field Guide
A systematic approach to diagnosing why WebSocket connections drop, covering proxy timeouts, idle timeouts, load balancer quirks, and client-side keepalive failures.
Debugging gRPC Status Code Errors: Root Causes and Fixes
A practical guide to debugging gRPC status code errors, covering non-obvious causes like proxy interference, deadline propagation, and client/server version mismatches.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Tracking Down a 200 MB Leak with Python Memory Profilers
A production API was silently leaking 200 MB of RAM every hour. Here's how memory profilers found the culprit—a forgotten NumPy array reference—and how you can apply the same techniques.
Reading CPU Flame Graphs: What the Hot Colors Actually Tell You
Flame graphs are everywhere, but most engineers read them wrong. Here's how to identify real bottlenecks, avoid common misinterpretations, and turn profile data into actionable fixes.
When Logs Lie: The Gaps Between What You Log and What Actually Happened
Logs are the first thing we reach for during an incident. But they can be misleading, incomplete, or outright wrong. Here's when to trust them and when not to.
Adding Observability to a 500K-Line Monolith Without a Rewrite
Adding structured logging, distributed tracing, and metrics to a legacy monolith without a full rewrite. Real code examples and a war story from a 500K-line codebase.
Distributed Tracing: Following a Single Request Across Microservices
Distributed tracing lets you follow a request as it hops across services. I'll show you how trace context propagates, why sampling matters, and how tracing helped us debug a 5-second latency spike in production.
Structured Logging in JSON: Fields, Schemas, and Pitfalls from Production
A practical guide to designing JSON log schemas that are queryable, consistent, and actually useful in production — with field recommendations and a war story.