How this site works

When you opened this page, your browser and this server had a short conversation. Here is each step, with timings from your own visit.

1. Your browserasks for the page
2. DNSfinds the address
3. Firewalllets web traffic in
4. Caddyencrypts and answers
5. FilesHTML, CSS, notes

Your visit, measured

Measuring your visit.

Step by step

1. Finding the server

   Your browser asks the domain name system for this site's address. The name is registered with the free service DuckDNS and points to the server's fixed public address.

2. Passing the firewall

   The cloud provider's firewall sits in front of the server. It drops everything except web traffic on ports 80 and 443 and administrator access from one trusted address.

3. Securing the connection

   The web server Caddy completes the encrypted handshake. It obtains its certificate from Let's Encrypt and renews it automatically, so nobody has to remember to do it. Plain HTTP requests are redirected to HTTPS.

4. Answering the request

   Most pages are plain files read from disk. Notes are written in Markdown and turned into HTML by Caddy when you open them. Two small internal services sit behind Caddy and are only reachable through it. One counts visits, and the other can run the playground's molecular dynamics sandbox. Every other address under /api is refused.

5. Arriving in your browser

   The response is compressed, and it carries security headers that tell your browser what this page is allowed to do. These are the headers this server sent just now:

   Header	What it does

Round-trip test

Sends ten small requests to the server, one after another, and times each round trip.