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.
Stale lock bug: how locks that are never refreshed cause outages
A lock is acquired, the operation succeeds, but the lock is never released or refreshed. Other processes wait until the lock TTL expires, causing delays or outages.
Tenant cache leak: how to debug cross-tenant data exposure through caching
A user from Tenant A sees data from Tenant B because the cache key does not include the tenant identifier. The cache is leaking data across tenants.
Observability missing logs: how to debug gaps in logging and monitoring
A critical error happened in production but there are no logs for it. The log level is too high, logs are dropped under load, or the log pipeline has a silent failure.
Log says success but the user still fails: how to debug misleading logs
Your application logs 'Operation completed successfully' but the user sees an error or gets no result. The log is lying — it is logging intent, not outcome.
Background job stuck: how to debug jobs that never complete
A background job enters the queue, a worker picks it up, and then nothing. The job never completes, never fails, and never retries. It is stuck in limbo.
Race condition in payment flow: how to debug concurrent payment issues
Two requests hit the payment endpoint at the same time. Both check the balance, both see enough funds, and both deduct. The user is charged twice.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Debugging Webhook Delivery Failures: What the Logs Don't Tell You
HTTP 200 doesn't mean your webhook was processed. A practical guide to the network and middleware layers that silently drop webhooks.
Debugging HTTP Headers with curl: From Basic Flags to Packet-Level Inspection
A practical guide to inspecting HTTP request and response headers with curl, covering basic flags, debugging tricky issues, and understanding what your headers are really doing.
Debugging WebSocket Real-Time Features: Packet Loss, Reconnect Storms, and Silent Failures
WebSocket debugging goes beyond console.log. I cover packet capture with tcpdump, reconnect backoff strategies, and a war story about a silent failure that took down a production chat feature.
Rest API Design Mistakes That Inject Bugs Into Your System
Most API bugs aren't in the implementation—they're baked into the contract. Here are the design errors I've seen cause the most production incidents.
Blameless Postmortems: How We Fixed Root Causes Without Firing Anyone
A practical guide to running postmortems that focus on systemic failures, not individual mistakes. Includes a real incident breakdown from a production database outage.
Chaos Engineering at 3 AM: When Our Kubernetes Cluster Lost Its DNS
We ran a chaos experiment on our Kubernetes cluster and found a subtle DNS misconfiguration that would have caused a cascading failure. Here's how we did it and what we learned.