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.
3 playbooks in Backend & APIs
Debugging Retry Bugs
Retry issues often hide the first failure and create duplicate work.
Debugging Idempotency Bugs
How to debug duplicate writes when clients, webhooks, or workers retry after ambiguous failures.
Debugging Payment Races
How to reason about duplicate charges, concurrent refunds, and payment workflow compensation.
Structured investigations for the failure modes engineers meet in real systems.
Debugging CORS Errors in Browser-Based APIs
Learn how to identify and fix CORS errors in browser clients calling APIs, with actionable steps and real-world debugging examples.
Diagnosing tRPC Procedure Errors in Next.js Apps
Pinpoint and resolve tRPC procedure errors in Next.js projects. Covers error signatures, hidden pitfalls, common root causes, and real-world troubleshooting steps.
Debugging 500 Errors on Nuxt Server API Routes
Nuxt server API routes returning HTTP 500 errors are common but often tricky. This guide gives you concrete steps and real fixes for Vue/Nuxt stacks.
Express Middleware Not Executing in Order: A Debugging Guide
Diagnose and fix Express middleware that executes out of order or skips entirely. Covers route ordering, next() misuse, and async pitfalls.
Fastify Plugin Not Registered: Debugging the 'Missing Plugin' Error
A direct guide to debugging Fastify's 'plugin not registered' error, covering encapsulation, async registration, and dependency ordering.
Express-Session Not Saving Between Requests: The Real Causes
A debugging guide for when express-session fails to persist session data across HTTP requests in Node.js applications.
Long-form thinking on debugging habits, observability, and the systems around the bug.
Debugging Third-Party API Issues: A Systematic Approach
A practical guide to diagnosing and fixing third-party API integration problems, with real-world examples and a step-by-step debugging framework.
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.
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.