# Installing Additional Packages

Railpack supports installing additional versioned packages from
[Mise](https://mise.jdx.dev/), or packages from Apt.

## Mise

You can set the `RAILPACK_PACKAGES` environment variable to install additional
packages from Mise.

For example, this installs the latest versions of Node and Bun, and Python 3.10.

```bash
RAILPACK_PACKAGES="node bun@latest python@3.10"
```

You can find a list of available packages in the [Mise registry](https://mise.jdx.dev/registry.html).

## Apt

Apt packages are split into those needed for the build and those needed at
runtime.

You can set the `RAILPACK_BUILD_APT_PACKAGES` and `RAILPACK_DEPLOY_APT_PACKAGES`
environment variables to install additional Apt packages during the build and
deployment steps respectively.

In this example, we install `build-essential` during the build step and `ffmpeg`
at runtime.

```bash
RAILPACK_BUILD_APT_PACKAGES="build-essential"
RAILPACK_DEPLOY_APT_PACKAGES="ffmpeg"
```