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

# Adding Packages

> Customize the packages available to your code

Your script can use third-party packages installed from [PyPI](https://pypi.org/)
or [npm](https://docs.npmjs.com/about-npm/).

<Note>
  Customizing packages is currently only supported for Python and JavaScript/TypeScript.
</Note>

## Install packages

To use additional packages you'll need to create a [custom runtime](/guides/custom-runtimes) on
Riza and configure it with specific packages, such as `pandas` or `prisma`.

When you invoke the [Execute Code API Endpoint](/api-reference/command/execute-code), you can specify
a custom runtime revision ID as a parameter to execute code in the context of that runtime.

### Python

To create a custom runtime for Python, you'll need to supply the contents of a
typical `requirements.txt` file with the packages you want installed.

```requirements.txt theme={null}
pandas==1.5.3
markdown==3.7
```

See the [Custom
Runtimes guide](/guides/custom-runtimes#create-a-python-custom-runtime) for
a complete Python example.

### JavaScript/TypeScript

To create a custom runtime for JavaScript/TypeScript, you'll need to supply the
contents of a typical `package.json` file with the packages you want installed.
You can send a full `package.json` and we'll ignore all but the `dependencies`
field.

```json package.json theme={null}
{
  "dependencies": {
    "prisma": "^4.16.2",
    "marked": "^15.0.6"
  }
}
```

See the [Custom
Runtimes guide](/guides/custom-runtimes#create-a-javascript-custom-runtime) for
a complete JavaScript example.