Show HN: Toolkit – Visual Simulators for How Internet Protocols and Systems Work

The step-by-step timeline format is really well done. I've bookmarked the OAuth page specifically — explaining the redirect flow visually makes it so much clearer than the spec's wall of text.

One thing I'd love to see added: a WebSocket upgrade visualization. The initial HTTP handshake → 101 Switching Protocols → full-duplex flow is something a lot of devs use daily (via Socket.io or similar) but never actually understand at the protocol level. It would fit perfectly with your existing format.

Also, the HTTPS section could benefit from showing the 0-RTT resumption failure case — what happens when the server rejects the early data and falls back to a full handshake. That's the part that catches people off guard in production when they're debugging intermittent TLS issues.

Really nice work overall. These kinds of interactive explainers stick way better than reading RFCs.