Shopify
Shopify Inventory Says In Stock and Checkout Says Otherwise
The storefront cached availability, the customer added to cart, and checkout disagreed. Here is where the state diverges and what to do about it.
Shopify
Shopify App Proxy Returns 404 and the Reason Is Never Obvious
The proxy path, the subpath prefix, and the actual route all have to line up. Here is the checklist and how to verify the signature properly.
PostgreSQL
Postgres deadlock detected: Reading the Log and Fixing the Lock Order
Two transactions each hold what the other wants. Here is how to read the deadlock report, find both statements, and restructure so it cannot happen again.
Docker
exec format error: The ARM64 and AMD64 Mismatch Explained
Your image builds on a Mac and dies in production. What the error means, how to check an image's architecture, and how to build multi arch properly.
Next.js
Next.js Dynamic Server Usage: Understanding the Static and Dynamic Boundary
Your build fails because a page tried to read a header. Here is what triggers dynamic rendering and how to decide what each route should be.
JavaScript
Module Not Found in Vite but Fine in Webpack
Same code, same package.json, different bundler, different result. The difference is resolution conditions and how strict each tool is.
PostgreSQL
Why Your Index Is Not Being Used: Reading EXPLAIN ANALYZE Line by Line
You added the index and the query is still slow. Here is how to read a Postgres query plan properly and find the row estimate error causing it.
Python
Debugging asyncio Deadlocks and the Blocking Call Checklist
Your async service handles ten requests a second and pegs one core. Somewhere a synchronous call is blocking the event loop.
Shopify
The Liquid Loop That Adds Three Seconds to Your Shopify Page
Liquid has no query log, so N+1 problems are invisible until the page is slow. Here is how to find them with Server-Timing and how to restructure the loops.
Kubernetes
OOMKilled: Why Your Container Died and Your Metrics Showed Nothing
Exit code 137, a memory graph that looks perfectly healthy, and no application error. Here is why your monitoring missed it and how to find the real number.
Networking
GraphQL Returns 200 With Your Error Inside It
Every response is a success as far as HTTP is concerned. That one design decision breaks monitoring, retries, and error handling unless you plan for it.
Node.js
ERR_REQUIRE_ESM: The Complete Guide to Why Your Import Broke
The error that shows up when a dependency goes ESM only. What it means, the five ways to fix it, and how to pick the right one.