> ## Documentation Index
> Fetch the complete documentation index at: https://docs.microsandbox.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Using with VS Code

> Edit files and run tools in a sandbox with VS Code Remote-SSH

Connect VS Code to a local or cloud sandbox over SSH. Your files, terminal, and remote extensions run inside the sandbox.

Before you start, install [VS Code Remote-SSH](https://code.visualstudio.com/docs/remote/ssh) and have a running sandbox with an image that meets [VS Code's Linux requirements](https://code.visualstudio.com/docs/remote/linux). Alpine is not supported by Remote-SSH.

## Connect to your sandbox

<Steps>
  <Step title="Set up SSH">
    Run these commands on your host. The examples use `~/.ssh/id_ed25519`; use your own key path if different. If you need a key, create one with `ssh-keygen -t ed25519`.

    <Tabs>
      <Tab title="Cloud">
        Add your public key to the sandbox's **SSH keys** page in the dashboard, or use an existing organization SSH key. Copy the sandbox's SSH command, for example:

        ```bash theme={null}
        ssh crimson-summit-7fa1@msb.run
        ```

        Add this entry to `~/.ssh/config`, replacing `crimson-summit-7fa1` with your sandbox's slug:

        ```sshconfig theme={null}
        Host devbox.msb
          HostName msb.run
          User crimson-summit-7fa1
          IdentityFile ~/.ssh/id_ed25519
          IdentitiesOnly yes
        ```
      </Tab>

      <Tab title="Local">
        Authorize your public key and serve your sandbox, replacing `devbox` with its name:

        ```bash theme={null}
        msb ssh authorize --file ~/.ssh/id_ed25519.pub
        msb ssh serve devbox
        ```

        Leave that terminal running. Add this entry to `~/.ssh/config`:

        ```sshconfig theme={null}
        Host devbox.msb
          HostName 127.0.0.1
          Port 2222
          User root
          IdentityFile ~/.ssh/id_ed25519
          IdentitiesOnly yes
        ```
      </Tab>
    </Tabs>

    In another host terminal, run `ssh devbox.msb`. On first connection, verify the host key and type `yes` to trust it. Once connected, run `exit`.
  </Step>

  <Step title="Open VS Code">
    1. Open the Command Palette and select **Remote-SSH: Connect to Host...**.
    2. Select **devbox.msb**, then **Linux** if prompted.
    3. Wait for setup to finish, then use **File > Open Folder...** to open your project inside the sandbox.

    Clone or copy your project into the sandbox first; connecting does not copy host files. Use the integrated terminal for commands and the **Ports** view to access apps running in the sandbox.
  </Step>
</Steps>

## Troubleshooting

<AccordionGroup>
  <Accordion title="SSH will not connect">
    Check **View > Output > Remote - SSH** for the error. Confirm that the private key in `IdentityFile` matches an authorized public key. For cloud, check the sandbox slug and dashboard SSH keys. For local, keep `msb ssh serve` running and check that its port matches your SSH configuration.

    Leave **Remote.SSH: Remote Server Listen On Socket** disabled; use TCP forwarding.
  </Accordion>

  <Accordion title="Host key changed or forwarding disabled">
    For local sandboxes, serving a different sandbox on the same port can cause `MitmPortForwardingDisabled`. After verifying that the key change is expected, remove the old entry on your host:

    ```bash theme={null}
    ssh-keygen -R '[127.0.0.1]:2222'
    ssh devbox.msb
    ```

    Verify and accept the new key, then reconnect in VS Code. This command applies to the local configuration above. Investigate unexpected key changes; do not disable host-key checking.
  </Accordion>

  <Accordion title="VS Code Server or extensions fail">
    Check **Remote - SSH** and **Log (Remote Extension Host)** in the Output panel. Verify the image's [libraries and architecture](https://code.visualstudio.com/docs/remote/linux), available memory, disk space, and download access.

    If the terminal works but extensions fail, disable remote extensions and re-enable them one at a time. Install missing guest libraries or a compatible extension build; increase memory if logs show an out-of-memory kill.
  </Accordion>
</AccordionGroup>

See [SSH](/sandboxes/ssh) for forwarding, custom ports, and [idle timeouts](/sandboxes/ssh#inactivity-timeout).