> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/open-source/use-harness-open-source/gitspaces/develop-in-gitspaces/env-variables.md).

# Environment Variables

This guide walks you through the steps required to set environment variables for your containers without altering the container images. This feature allows you to manage application configurations and customize development environments to suit your specific requirements.

You can define environment variables in your container using the `containerEnv` property in the `devcontainer.json` specification. (Read more about the [devcontainer.json configuration](https://containers.dev/implementors/json_reference).)

#### What is "containerEnv"? <a href="#what-is-containerenv" id="what-is-containerenv"></a>

`containerEnv` is a set of name-value pairs where each pair defines an environment variable and its corresponding value. This property sets these variables directly on the Docker container itself, meaning their scope is limited to all processes running inside the container.

#### Adding containerEnv to devcontainer.json <a href="#adding-containerenv-to-devcontainerjson" id="adding-containerenv-to-devcontainerjson"></a>

Here’s how you can include the `containerEnv` property in your `devcontainer.json` configuration:

```
"containerEnv": {
    "MY_CONTAINER_VAR": "some-value-here"
}
```

This property is static for the container’s lifecycle.

Here’s an example of a complete `devcontainer.json` file with the containerEnv property:

```
{
    "image": "mcr.microsoft.com/devcontainers/javascript-node:1-18-bullseye",
    "containerEnv": {
        "VAR1": "value1",
        "VAR2": "value2"
    }
}
```

#### Verifying Environment Variables <a href="#verifying-environment-variables" id="verifying-environment-variables"></a>

Once you’ve added the `containerEnv` property, you can verify the environment variable setup by checking the container logs while creating a Gitspace through the Harness UI.

![](/files/1fGcFyyLjvzciwPuvgVg)

#### Using Environment Variables <a href="#using-environment-variables" id="using-environment-variables"></a>

You can start using your environment variables directly within your Gitspaces. To verify, open your Gitspace and launch the Terminal.

Run the following command:

`env`

This will display the environment variables you’ve configured, as shown in the output below.

<img src="https://github.com/user-attachments/assets/429d389a-5ee3-4023-9ca3-fd3bc0fac869" alt="env 2" width="958">