Short, illustrated explainers covering how the pieces of website monitoring fit together — written for the people who own the site, not for SREs.
Short, illustrated explainers on how the moving parts of a website actually work: DNS resolution, TLS certificates and the handshake, Core Web Vitals and what makes each metric move, HTTP status codes, crawling and indexing, and how monitoring checks are run and confirmed.
Written for people who own or manage a site rather than for SREs — enough depth to diagnose a real problem, no assumed background in networking. Every guide includes a diagram of the flow and a section on how that layer typically breaks.
If something is broken right now, start with the guide for the layer that's failing. If you're setting monitoring up for the first time, the DNS and SSL guides cover the two things that most often take a site down without warning.