langflow/docs/docs/Develop/install-custom-dependencies.md

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Install custom dependencies	/install-custom-dependencies

To install custom dependencies in your Langflow environment, add them with your package manager.

Create a virtual environment for local testing

When testing locally, use a virtual environment to isolate your dependencies and prevent conflicts with other Python projects.

For example, if you want to experiment with matplotlib with Langflow:

# Create and activate a virtual environment
uv venv YOUR_LANGFLOW_VENV
source YOUR_LANGFLOW_VENV/bin/activate

# Install langflow and your additional dependency
uv pip install langflow matplotlib

If you're working within a cloned Langflow repository, add dependencies with uv add because there is already a pyproject.toml file for uv to reference.

uv add langflow matplotlib

Add dependencies to the Langflow project

When contributing to Langflow itself, add dependencies to the project's configuration. Langflow uses a workspace with two packages:

• The main package (root level): For end-user features and main application code
• The base package (in src/backend/base): For core functionality and shared code

Dependencies can be added in different groups:

• Regular dependencies: Core functionality needed to run the package
• Development dependencies: Tools for testing, linting, or debugging are added in the [dependency-groups.dev] section
• Optional dependencies: Features that users can optionally install are added in the[project.optional-dependencies]

There are three ways to add a package using make commands:

• Add to main package dependencies (for end-user features):

make add main="matplotlib"

• Add to development tools (for testing, linting, debugging):

make add devel="matplotlib"

• Add to base package dependencies (for core functionality):

make add base="matplotlib"

You can also add these dependencies manually to the pyproject.toml file:

[project]
dependencies = [
    "matplotlib>=3.8.0"
]

• Or as an optional dependency:

[project.optional-dependencies]
plotting = [
    "matplotlib>=3.8.0",
]

The make commands add the dependency with uv add and update the uv.lock file in the appropriate location.