Contributing to Langflow

This guide is intended to help you get started contributing to Langflow. As an open-source project in a rapidly developing field, we are extremely open to contributions, whether it be in the form of a new feature, improved infra, or better documentation.

To contribute to this project, please follow the fork and pull request workflow.

Reporting bugs or suggesting improvements

Our GitHub issues page is kept up to date with bugs, improvements, and feature requests. There is a taxonomy of labels to help with sorting and discovery of issues of interest. See this page for an overview of the system we use to tag our issues and pull requests.

If you're looking for help with your code, consider posting a question on the GitHub Discussions board. Please understand that we won't be able to provide individual support via email. We also believe that help is much more valuable if it's shared publicly, so that more people can benefit from it.

Describing your issue: Try to provide as many details as possible. What exactly goes wrong? How is it failing? Is there an error? "XY doesn't work" usually isn't that helpful for tracking down problems. Always remember to include the code you ran and if possible, extract only the relevant parts and don't just dump your entire script. This will make it easier for us to reproduce the error.
Sharing long blocks of code or logs: If you need to include long code, logs or tracebacks, you can wrap them in <details> and </details>. This collapses the content so it only becomes visible on click, making the issue easier to read and follow.

Contributing code and documentation

You can develop Langflow locally via uv + NodeJS.

Clone the Langflow Repository

Navigate to the Langflow GitHub repository and press "Fork" in the upper right-hand corner.

Add the new remote to your local repository on your local machine:

git remote add fork https://github.com/<your username>/langflow.git

We also provide a .vscode/launch.json file for debugging the backend in VSCode, which is a lot faster than using docker compose.

Prepare the environment

Setting up hooks:

make init

This will set up the development environment by installing backend and frontend dependencies, building the frontend static files, and initializing the project. It runs make install_backend, make install_frontend, make build_frontend, and finally uv run langflow run to start the application.

It is advised to run make lint, make format, and make unit_tests before pushing to the repository.

Run locally (uv and Node.js)

Langflow can run locally by cloning the repository and installing the dependencies. We recommend using a virtual environment to isolate the dependencies from your system.

Before you start, make sure you have the following installed:

uv (>=0.4)
Node.js

Then, in the root folder, install the dependencies and start the development server for the backend:

make backend

And the frontend:

make frontend

Run documentation

The documentation is built using Docusaurus. To run the documentation locally, run the following commands:

cd docs
npm install
npm run start

The documentation will be available at localhost:3000 and all the files are located in the docs/docs folder.

Opening a pull request

Once you wrote and manually tested your change, you can start sending the patch to the main repository.

Open a new GitHub pull request with the patch against the main branch.
Ensure the PR title follows semantic commits conventions.
- For example, feat: add new feature, fix: correct issue with X.
Ensure the PR description clearly describes the problem and solution. Include the relevant issue number if applicable.