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.
1 playbook in Observability & Performance
Structured investigations for the failure modes engineers meet in real systems.
Debugging LCP: Largest Contentful Paint Too Slow
A practical guide to diagnosing and fixing slow Largest Contentful Paint in real-world web applications, with specific commands, metrics, and war stories.
Debugging Cumulative Layout Shift (CLS): A Production Engineer's Guide
This guide provides concrete steps to diagnose and fix CLS issues in production, with real commands and specific tools.
JavaScript Long Task Blocking Main Thread: Diagnosis and Fixes
A practical guide to identifying and fixing JavaScript long tasks that block the browser's main thread, causing jank and poor user experience.
Debugging High Interaction to Next Paint (INP) Scores
A practical guide to diagnosing and fixing poor Interaction to Next Paint (INP) scores, covering event handler delays, rendering bottlenecks, and real-user monitoring.
Debugging JavaScript Garbage Collection Pauses That Kill Responsiveness
Learn how to identify and fix long GC pauses in Node.js and browser JavaScript using Chrome DevTools, Node --trace-gc, and heap snapshots.
OpenTelemetry Traces Not Appearing: Debugging Missing Spans in Production
A debugging guide for when OpenTelemetry traces are not appearing in your observability backend. Covers common and non-obvious causes like sampling misconfiguration, exporter timeouts, and context propagation failures.
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.
Reading Distributed Traces to Find Latency: A Field Guide
Tracing tools generate a firehose of data. Here's how to filter the signal from the noise and actually find the root cause of high latency.
Why Your P99 Latency Is Lying to You (and What to Use Instead)
The 99th percentile is the go-to metric for tail latency, but it's easy to fool. Here's a real outage caused by trusting P99, and how to build a more honest monitoring stack.
Reading Flame Graphs: The Non-Obvious Patterns That Reveal Real Bottlenecks
Flame graphs are everywhere in performance profiling, but most engineers only scratch the surface. Here are the patterns that actually tell you where your code is slow.
Observability vs. Monitoring: Why Your On-Call Rotation Still Wakes You Up at 3 AM
Monitoring tells you something is broken. Observability lets you figure out why—without guessing, without SSH, without restarting the pod.