Networking
Cloudflare 526: The Redirect Loop Behind One Setting
Flexible gives you an infinite redirect. Full strict gives you a 526. The documentation says Full or higher, and higher is the one that breaks.
Node.js
EMFILE: Too Many Open Files, and Why Raising ulimit Is Wrong
The quick fix is raising ulimit. The real question is what is holding thousands of descriptors open and never closing them.
Shopify
Shopify Webhooks You Are Not Receiving
The webhook is registered, orders are being created, and nothing arrives. Here is where they go and how to stop being unsubscribed.
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: Fix 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: The Static-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 Used: Reading EXPLAIN ANALYZE
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.