zotty

README

zotty

zotty (zero-overhead-tty) is a small terminal bridge for the zot web UI (web.zot.sh) or similar. It runs on the same machine as your zot host and gives the web UI a real shell in a pseudo-terminal. zot itself is not involved or changed.

Security: zotty grants full shell access as the user running it. Anyone who can reach it and has the token can run any command. Keep it on localhost and expose it only through a private tunnel such as Tailscale. Do not publish it through a public tunnel.

Run

go build -o zotty .
./zotty serve

On first start it creates a random token in your user config directory (macOS: ~/Library/Application Support/zotty/token, mode 0600) and prints it. In the web UI, open the terminal button in the sidebar footer and enter the bridge URL and this token.

Flags

Flag	Default	Description
--listen	127.0.0.1:7789	Address to listen on. A non-loopback address logs a warning.
--token-file	user config dir	Token file, created if missing.
--origins	https://web.zot.sh	Comma-separated browser origins allowed in addition to localhost.
--shell	$SHELL, then /bin/sh	Shell to start as a login shell.
--dir	home directory	Working directory for new shells.
--upstream	off	Forward every path except /term and /health to this address, for example zot's --web listener 127.0.0.1:7787. Lets one tunnel serve zot and zotty.

Remote access with Tailscale

tailscale serve --bg --https=8443 http://127.0.0.1:7789

Then use https://<machine>.<tailnet>.ts.net:8443 as the terminal URL.

Remote access with cloudflared

Warning: a cloudflared tunnel is reachable from the public internet. Only the token protects the shell. Prefer Tailscale when you can.

Quick tunnel for zot and zotty (no Cloudflare account, no domain):

zot continuous serve --store ~/.zot-store --web 127.0.0.1:7787
zotty serve --upstream 127.0.0.1:7787
cloudflared tunnel --url http://127.0.0.1:7789

zotty serves /term and forwards everything else to zot. With the printed https://<random>.trycloudflare.com address, use:

• host URL: https://<random>.trycloudflare.com
• terminal URL: https://<random>.trycloudflare.com/term

The address changes on every start. Both endpoints keep their own token: the zot web token and the zotty token.

Named tunnel (Cloudflare account and your own domain): route zot and zotty through one hostname by path:

ingress:
  - hostname: zot.example.com
    path: ^/term
    service: http://127.0.0.1:7789
  - hostname: zot.example.com
    service: http://127.0.0.1:7787
  - service: http_status:404

Then use https://zot.example.com as the host URL and https://zot.example.com/term as the terminal URL.

Behavior

• One shell per connection. Closing the tab or reconnecting ends that shell (use tmux inside it for persistent sessions).
• At most 8 shells at a time.
• The token is sent in the first WebSocket message, not in the URL, so it does not appear in tunnel or proxy logs.
• Browser origins other than localhost and --origins are rejected.
• Unix only (macOS, Linux).

Protocol

WebSocket at /term:

Direction	Frame	Content
client to server	text, first	{"type":"auth","token":"...","cols":80,"rows":24}
client to server	text	{"type":"resize","cols":120,"rows":40}
client to server	binary	terminal input
server to client	text	{"type":"ready"} after authentication
server to client	text	{"type":"exit","code":0} when the shell exits
server to client	binary	terminal output

A wrong token closes the connection with status 1008, too many shells with 1013.

Test

go test -race ./...

License

MIT

Documentation

Overview

Command zotty (zero-overhead-tty) is a small terminal bridge for the zot web UI.

It serves a WebSocket endpoint that starts a login shell in a pseudo-terminal for each authenticated connection. It is independent of zot itself and grants full shell access as the user running it, so it listens on localhost by default and requires a token.