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Once a Devbox exists, you work in it through a terminal. There are two ways to get one, and they differ in what happens when you close it. An SSH connection lasts as long as your terminal does. A session is a terminal that lives on the Devbox, so whatever runs in it keeps going after you disconnect, and you can come back to it later.

SSH

For quick interactive work, and for tools that connect over SSH.

Session

For work that should outlive your connection, including a coding agent.

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Open a Shell with SSH

devbox ssh opens an interactive shell on the Devbox. The connection is tunneled through the Namespace API, so the Devbox needs no public IP address or open port.
Omit the name to pick a Devbox from a list:
Or name it to connect straight away:
Connecting to a stopped Devbox starts it first. The shell ends when you exit it or when your connection drops, and so does anything running in the foreground.

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Keep Work Running in a Session

A session is a named terminal that runs on the Devbox. Closing your terminal only detaches you from it: the shell and everything running in it keep going, with their output, until you reconnect. Sessions are tmux sessions managed by the Devbox.
Connect to a session by name. The session is created the first time you use the name:
Run the same command later to pick up where you left off. Run devbox session connect with no arguments to choose a Devbox and a session from a list.
A session is shared between the CLI and the dashboard. Start a build from your terminal, close the laptop, and check on it later from the dashboard in a browser. One client is attached at a time: connecting from a new place detaches the previous one. Create one session per stream of work, for example server for a dev server, tests for a test watcher, and shell for everything else. See devbox session to list sessions.

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Run a Coding Agent in a Session

A coding agent that works on the Devbox for a long stretch is the clearest case for a session. Over SSH, the agent stops when your laptop sleeps or your network drops. In a session, it carries on without you, and you can reconnect to see what it has done or give it the next task.
1

Connect to a session for the agent

2

Start the agent

Start your agent in the session, for example claude, codex, or amp, and give it a task.
3

Disconnect and come back later

Close your terminal while the agent works. Reconnect with the same command to check on it:
A session counts as activity for only 15 minutes after it is created, so a Devbox can stop for being idle while an agent is still working in it. Ask the agent to create a task marker while it works. See Running long tasks.

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Choose Between SSH and a Session

Use SSH for short interactive work, for piping local data into a command, and for tools that need an SSH connection. Use a session for anything you want to come back to: a dev server, a long build, or a coding agent. To run a command without a terminal at all, and keep its output to read later, use devbox exec instead.

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Next Steps

Executing Commands

Run commands without a terminal and read their output later.

IDEs

Open a Devbox in VS Code, Cursor, JetBrains, or Zed.

Running Long Tasks

Keep a Devbox running while a build or an agent works.
Last modified on October 2, 2026