yemu — TinyEMU RISC-V emulator

Boots Alpine Linux on RISC-V entirely inside your browser (wasm-interpreted CPU — no server involved). The rootfs is a large download (~250 MB compressed, cached after the first visit) and the first boot takes a while; the log below streams every step. Terminals attach from the Terminals tab via the TinyEMU VM session type — each gets its own telnet login on the one VM.

stopped attached terminals: none

(emulator not started — boot log will stream here)

yos — FreeBSD wasm userspace

Runs zsh, nvim, tmux and coreutils as wasm32 binaries on the yos process engine — no server, no VM, no kernel (~40 MB of tools on first start). yos is an OS-like engine with real multi-process support: it loads once per page, and every terminal attached from the Terminals tab via the yos session type gets its own fresh zsh session on the same engine.

stopped attached terminals: none

(yos not started — boot log will stream here)

yetty — a WebGPU terminal, running in your browser

This page runs the real yetty terminal compiled to WebAssembly. Everything below happens in your browser — the only server involvement is whatever a session type explicitly connects to.

Terminals tab

Click the ☰ button to open a new terminal. Pick a session type, fill in the details, hit Start. The ☰ button always sits below the newest terminal; open as many as you like.
Each terminal panel: click into it to type, drag the grip bar at its bottom edge to resize (the terminal re-wraps live), close it with × in its header.
Inside yetty, Ctrl+Shift+T opens another tab of the same session kind.
The boot overlay on a starting terminal collapses on its own; the console pill (top right of the panel) brings it back.

Session types

TinyEMU VM — Alpine Linux on an emulated RISC-V machine, fully in-browser. Each terminal gets its own telnet login on the shared VM.
yos — a FreeBSD-flavoured wasm userspace (zsh, nvim, tmux, coreutils), fully in-browser. One process tree per page: every terminal gets a fresh zsh on the same system — ps aux in one shell sees them all.
WebSocket shell — a raw PTY served by websocket-pty-server.py on a host you run.
Telnet / SSH — connect through a WebSocket↔TCP bridge (telnet-websocket.sh); SSH crypto runs in the browser, the bridge only relays encrypted bytes.
ygreeter — the ygui feature showcase (plots, images, diagrams, shaders), no shell.
lwIP relay — experimental in-browser TCP/IP stack; telnets to a real host:port through an L2 relay.

Engines tab

The TinyEMU VM and the yos userspace are page-shared engines: loaded at most once, attached to by any number of terminals, running independently of all of them. Start one manually to watch its boot log, or just open a terminal of that type — the engine starts automatically.

Deep links

Every session type can be opened straight from the URL: ?mode=yos, ?mode=temu, ?mode=websocket&url=ws://host:8090, ?mode=telnet&url=ws://host:8024, ?mode=ssh&user=you, ?mode=ygreeter.

Downloads and caching

The first visit downloads the terminal, its assets and — if used — the VM rootfs or the yos tools. All of it is cached in the browser in final, decoded form: later visits and additional terminals load from disk and only re-download files that actually changed in a release.