Installation

This guide will walk you through installing the Vellum Workflows SDK and setting up your development environment.

Prerequisites

The Vellum Workflows SDK requires Python 3.9 or higher. If you don’t have Python installed, you can download it from python.org.

Install uv (Recommended)

Install Python

We recommend using uv for package & environment management. If you don’t have uv installed:

$ # On macOS and Linux
> curl -LsSf https://astral.sh/uv/install.sh | sh
> 
> # On Windows
> powershell -c "irm https://astral.sh/uv/install.ps1 | iex"
> 
> # Or using pip
> pip install uv

Learn more about uv here

Install the Vellum Workflows SDK

Using uv (Recommended)

Using pip

$ uv add vellum-ai

Environment Setup

Set your Vellum API Key

To use most out-of-the-box Nodes and to push/pull to/from the Vellum UI, you’ll need a Vellum API key.

Get your API key: You can find this in Workspace Settings in Vellum. Note that API keys are Environment-scoped.
Set the environment variable:

macOS/Linux

Windows

$ export VELLUM_API_KEY=your-api-key-here

To make this permanent, add it to your shell profile:

$ echo 'export VELLUM_API_KEY=your-api-key-here' >> ~/.bashrc
> # or for zsh users:
> echo 'export VELLUM_API_KEY=your-api-key-here' >> ~/.zshrc

Create a Virtual Environment (Optional but Recommended)

It’s good practice to create a virtual environment for your project:

Using uv

Using venv

$ uv venv
> source .venv/bin/activate  # On Windows: .venv\Scripts\activate

Verify Installation

Test that everything is working correctly:

1 from vellum.workflows import BaseWorkflow
2 from vellum.workflows.nodes import BaseNode
3 
4 print("Vellum Workflows SDK installed successfully!")

Next Steps

Now that you have the SDK installed, you can:

Need Help?

If you don’t have a Vellum account yet, you can sign up for free here.

For additional support, visit our support page.