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.
GraphQL Subscription WebSocket Not Receiving Events
A step-by-step debugging guide for when GraphQL subscriptions fail silently over WebSocket—no events, no errors, just silence.
Apollo Client Cache Not Updating After Mutation: How to Force a Normalized Cache Refresh
If Apollo Client returns stale data after a mutation, your normalized cache isn't merging correctly. Here's how to diagnose cache policies, field merge functions, and cache redirects.
Svelte Store Not Updating Component – Reactive Assignment Pitfalls
Learn how to debug a Svelte store that doesn't trigger component re-renders. Covers reactive assignments, store subscriptions, and common Svelte reactivity gotchas.
Debugging Apollo Federation Subgraph Errors: A Field Guide
A practical guide to diagnosing and resolving errors from Apollo Federation subgraphs, including type resolution failures, entity lookup issues, and gateway-subgraph communication problems.
Svelte Reactive Statement Not Re-running After State Change
A deep guide to debugging Svelte reactive statements that fail to re-run: covering dependency tracking pitfalls, stale closures, and assignment traps.
SvelteKit load function errors: root cause analysis and fix patterns
A practical guide to diagnosing and fixing errors in SvelteKit load functions, covering server vs client context, serialization issues, and timing pitfalls.
Long-form thinking on debugging habits, observability, and the systems around the bug.
The Art of the Minimal Reproducible Example: A Debugging Superpower
A minimal reproducible example (MRE) is more than just a snippet — it's a tool that isolates the bug, saves time, and gets you faster answers. Here's how to build one that works, with a real-world war story.
Retry Storms: When Retries Make a Cascading Failure Worse
Retries seem like a safety net, but in a distributed system under load they can turn a small hiccup into a full outage. Here's how retry storms form and what to do about them.
Caching Bugs Are the Worst: A Postmortem on Stale Data Disasters
A deep dive into the most insidious caching bugs, with real postmortems and practical patterns to avoid stale-data disasters.
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.
Debugging Flaky Tests for Good: A Systematic Approach to Root Cause Analysis
Flaky tests waste time and erode trust. Here's how to find and fix the actual root cause instead of just rerunning.
Idempotency Keys: The Safety Net Your Payment API Needs
How idempotency keys prevent double charges, lost refunds, and data corruption in payment APIs. With real-world examples and edge cases you haven't considered.