This page performs a live, annotated https: request for its own source. It’s inspired by The Illustrated TLS 1.3 Connection and Julia Evans’ toy TLS 1.3.
It’s built on subtls, a pure-JS TLS 1.3 implementation that depends only on SubtleCrypto. Raw TCP traffic is carried via a WebSocket proxy.

Key Raw bytes in hexadecimal. Outgoing message annotations. Incoming message annotations.