tsshd is a UDP-based SSH server (and Go library) designed for unreliable networks, providing seamless client roaming and auto-reconnect. It works in conjunction with the tssh client (trzsz-ssh). The architecture is session-based: a standard SSH login spawns a tsshd process that listens on a UDP port (using KCP or QUIC transport), then the client switches to UDP communication, surviving network changes and temporary disconnections. The codebase implements a full-featured SSH replacement: session management, port forwarding (TCP/UDP), X11 and agent forwarding, terminal attach/detach, and a middleware system for custom session handlers. It also includes a reusable client library (SshUdpClient) for building custom SSH applications with roaming support. The project is well-maintained with extensive test coverage, CI/CD, and multi-platform support (Linux, macOS, Windows, FreeBSD).