Build Websites
That Actually Work

'Error unprotecting the session cookie' in ASP.NET Core means the Data Protection keys were lost. What I reproduced, the different messages each cause produces, and the Program.cs fix for IIS.

Each issue in our own PageSpeed report and exactly what we changed - code splitting, the fade-in that hid our headline, analytics on interaction, two fixes that backfired - plus e-commerce speed and security headers.

Our own benchmark of gzip, Brotli and zstd (body size, requests per second, CPU), and the Cloudflare settings this site runs: what is on, what is off, and what a shop must never cache.

The page loads with no styling and the console says ChunkLoadError. The build is fine and the files are on the server. The HTML asking for them is three hours old and came from your CDN, and it is still naming the chunks from the previous build.

You deployed, the database says the change is there, and the live page still shows the old content. Before you start debugging, send one request and read a single header. It will tell you which of two completely different problems you have.

Every guide to deploying ASP.NET Core on Plesk stops at "dotnet publish and upload the folder". Mine all went wrong after that step. Here are the five errors in the order you meet them, and what each one actually means.

Most guides to running Next.js on IIS assume a VPS you control and a reverse proxy to PM2. On Plesk shared Windows hosting you have neither. Here is the setup that works, and the four failures that cost me the most time.

A production build baked http://localhost:5080 into the live bundle. The cause was a .env.local file that Next.js loads during next build and ranks above .env.production. Here is the precedence order, a ten-line way to prove it on your own project, and the rename that fixes it permanently.

An index is how reads survive scale; idempotency is how writes survive retries. What each one fixes, why composite column order decides everything, why an idempotency key needs a UNIQUE constraint, and the migration-history failure where both ideas meet.