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Nu runs as three Compose services, defined in ~/.nu/compose.yaml: They run as your user, from the UID and GID in ~/.nu/.env, so the files in ~/.nu stay yours. compose.yaml is replaced on every update. Put your changes in ~/.nu/compose.override.yaml, which Compose merges in. To stay on a version, set NU_VERSION in ~/.nu/.env, such as NU_VERSION=0.2 for the latest 0.2 release. Manage the services with docker compose from ~/.nu:
Nu uses under 1 GB of memory when idle. Give it 2 CPUs and 4 GB so browser tasks and builds in the sandbox have room. On a smaller machine, lower the sandbox’s mem_limit so a large build can’t starve the rest of Nu. The kernel keeps each turn’s record for a year. To change that, set REBUNO_RETENTION in ~/.nu/.env to a duration, such as REBUNO_RETENTION=2160h for 90 days.

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Network

Nu publishes one port, 4122, and only on localhost. The terminal client and the browser handoff pages use it. To use the client from another machine, see Remote access. The kernel’s port stays inside the Compose network. Other services there can scrape its Prometheus metrics at nu:4117/metrics.

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Remote access

The terminal client can talk to Nu on another machine, such as a home server. Install only the client there:
Nu listens only on the server’s own loopback, so reach it through an SSH tunnel:
Then give the client the server’s terminal token:
The client saves the address and token in ~/.nu/client.json. Everything else stays on the server: chats, memory, secrets, packages, and settings. Commands such as nu login, nu install ./my-package, and nu mcp add act on the server, and sign-in redirects open in the browser on your machine.
The token gives full control of Nu. Don’t expose port 4122 to the internet. Use an SSH tunnel, a private network such as Tailscale, or an HTTPS proxy.

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Dashboard

The Rebuno dashboard shows every turn step by step, along with pending approvals and the policy. It is optional:
Open http://localhost:4116, or set NU_DASHBOARD_PORT for another port. It holds the kernel’s admin token, so it only listens on localhost. To start it with the rest of Nu, add COMPOSE_PROFILES=dashboard to ~/.nu/.env.

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Without Docker

Nu can also run straight from a checkout, with Postgres and the rebuno kernel on your PATH:
pnpm nu opens the client. NU_HOME sets the data directory, and NU_DB_URL points Nu at an existing Postgres database. Without Docker there is no sandbox.