Tailscale Ships a Bare-Bones Clone to Explain Its Own Magic
Tailscale has published a blog post and companion project called Tailcat, a minimal reimplementation of core Tailscale functionality built without using Tailscale's own client software. The idea is educational: rather than treating NAT traversal, WireGuard key exchange, and peer coordination as black-box magic, Tailcat exposes a simplified version of the plumbing so developers can see how a mesh VPN actually establishes direct connections between devices behind different networks.
This fits a pattern of infrastructure companies open-sourcing simplified versions of their internals to build trust and developer goodwill, similar to how database or queueing vendors sometimes publish toy implementations of their consensus protocols.
The project isn't meant to replace Tailscale in production, but as a teaching tool for engineers curious about coordination servers, STUN-like hole punching, and key distribution.