# Work with Dev Containers

The dev container integration appears in your Coder dashboard, providing a visual representation of the running environment:

![Two dev containers running as sub-agents in a Coder workspace](/beta-docs/images/user-guides/devcontainers/devcontainer-running.png)*Dev containers appear as sub-agents with their own apps, SSH access, and port forwarding*

## SSH access [#ssh-access]

Each dev container has its own agent name, derived from the workspace folder (e.g., `/home/coder/my-project` becomes `my-project`).
You can find agent names in your workspace dashboard, or see [Agent naming](/beta-docs/@main/user-guides/devcontainers/#agent-naming) for details on how names are generated.

<a id="using-the-coder-cli"></a>

### Use the Coder CLI [#use-the-coder-cli]

The simplest way to SSH into a dev container is using `coder ssh` with the workspace and agent name:

```console
coder ssh <workspace>.<agent>
```

For example, to connect to a dev container with agent name `my-project` in workspace `my-workspace`:

```console
coder ssh my-workspace.my-project
```

To SSH into the main workspace agent instead of the dev container:

```console
coder ssh my-workspace
```

<a id="using-openssh-config-ssh"></a>

### Use OpenSSH (config-ssh) [#use-openssh-config-ssh]

You can also use standard OpenSSH tools after generating SSH config entries with `coder config-ssh`:

```console
coder config-ssh
```

This creates a wildcard SSH host entry that matches all your workspaces and their agents, including dev container sub-agents.
You can then connect using:

```console
ssh my-project.my-workspace.me.coder
```

The default hostname suffix is `.coder`.
If your organization uses a different suffix, adjust the hostname accordingly.
The suffix can be configured via [`coder config-ssh --hostname-suffix`](/beta-docs/@main/reference/cli/config-ssh/) or by your deployment administrator.

This method works with any SSH client, IDE remote extensions, `rsync`, `scp`, and other tools that use SSH.

## Web terminal access [#web-terminal-access]

Once your workspace and dev container are running, you can use the web terminal in the Coder interface to execute commands directly inside the dev container.

![Coder web terminal with dev container](/beta-docs/images/user-guides/devcontainers/devcontainer-web-terminal.png)

## IDE integration (VS Code) [#ide-integration-vs-code]

You can open your dev container directly in VS Code by:

1. Selecting **Open in VS Code Desktop** from the dev container agent in the Coder web interface.
2. Using the Coder CLI:

   ```console
   coder open vscode <workspace>.<agent>
   ```

   For example:

   ```console
   coder open vscode my-workspace.my-project
   ```

VS Code will automatically detect the dev container environment and connect appropriately.

While optimized for VS Code, other IDEs with dev container support may also work.

## Port forwarding [#port-forwarding]

Since dev containers run as sub-agents, you can forward ports directly to them using standard Coder port forwarding:

```console
coder port-forward <workspace>.<agent> --tcp 8080
```

For example, to forward port 8080 from a dev container with agent name `my-project`:

```console
coder port-forward my-workspace.my-project --tcp 8080
```

This forwards port 8080 on your local machine directly to port 8080 in the dev container.
Coder also automatically detects ports opened inside the container.

<a id="exposing-ports-on-the-parent-workspace"></a>

### Expose ports on the parent workspace [#expose-ports-on-the-parent-workspace]

If you need to expose dev container ports through the parent workspace agent (rather than the sub-agent), you can use the [`appPort`](https://containers.dev/implementors/json_reference/#image-specific) property in your `devcontainer.json`:

```json
{
  "appPort": ["8080:8080", "4000:3000"]
}
```

This maps container ports to the parent workspace, which can then be forwarded using the main workspace agent.

## Dev container features [#dev-container-features]

You can use standard [dev container features](https://containers.dev/features) in your `devcontainer.json` file.
Coder also maintains a [repository of features](https://github.com/coder/devcontainer-features) to enhance your development experience.

For example, the [code-server](https://github.com/coder/devcontainer-features/blob/main/src/code-server) feature from the [Coder features repository](https://github.com/coder/devcontainer-features):

```json
{
  "features": {
    "ghcr.io/coder/devcontainer-features/code-server:1": {
      "port": 13337,
      "host": "0.0.0.0"
    }
  }
}
```

<a id="rebuilding-dev-containers"></a>

## Rebuild dev containers [#rebuild-dev-containers]

When you modify your `devcontainer.json`, you need to rebuild the container for changes to take effect.
Coder detects changes and shows an **Outdated** status next to the dev container.

![Dev container showing Outdated status with rebuild option](/beta-docs/images/user-guides/devcontainers/devcontainer-outdated.png)*The Outdated indicator appears when changes to devcontainer.json are detected*

Select **Rebuild** to recreate your dev container with the updated configuration.