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Contributing Guide

Ways you can Contribute

We're open to contributions and there are many ways that you can make one.

  • You can suggest new features.
  • You can help review new features.
  • You can submit new components.
  • You can let us know if there are bugs.
  • You can let us know if the components in this library help you.

Open an Issue

You can submit an issue here. Issues allow us to keep track of a conversation about this repository and it is the preferred communication channel for bugs related to this project.

Suggest a New Feature

This project started because we wanted to offer support for word embeddings for more languages. The first feature we added was support for FastText, which offers embeddings for 157 languages. We later received a contribution from a community member for BytePair embeddings, which offers support for 275 languages. We weren't aware of these embeddings but we were exited to support more languages.

Odds are that there are many more tools out there that the maintainers of this project aren't aware of yet. There may very well be more embeddings, tokenziers, lemmatizers and models that we're oblivious to but can help Rasa developers make better assistants.

The goal of this project is to support more of these sorts of tools for Rasa users. You can help out the project just by letting us know if there's an integration missing! If you do not have the time to contribute a component yourself then you can still contribute to the effort by letting us know what components might help you make a better assistant.

Share an Observation

If the tools that we offer here turn out to be useful then we'd love to hear about it. We're also interested in hearing if these tools don't work for your usecase. Any feedback will be shared with the research team at Rasa. We're especially keen to hear feedback on the performance of the word embeddings for Non-English languages. You can leave a message either on the github issue list or on the Rasa forum.

Adding a new Component

There's a balance between allowing experimentation and maintaining all the code. This is why we've come up with a checklist that you should keep in mind before you're submitting code.

  1. If you want to contribute a new component please make an issue first so we can discuss it. We want to prevent double work where possible and make sure the proposed component is appropriate for this repository.
  2. New tools that are added here need to be plausibly useful in a real life scenario. For example, we won't accept a component that adds gaussian noise to the features.
  3. Think about unit tests. We prefer to standardise unit tests as much as possible but there may be specific things you'd like to check for.
  4. Check the guides! There's a great custom components guide on the Rasa documentation page. If you get stuck, you're free to start an issue on this repository or to start a thread on our forum.

Removing a Component

Just like components can be added, they can also be removed. Historically, we've removed components when we barely saw usage in the community or when the community felt that the tools were cumbersome to use and didnt contribute to the Rasa pipeline. The removal typically takes place whenever Rasa is updated and the new mayor version (from 1.x to 2.x, and from 2.x to 3.x).


We run automated tests via GitHub actions but you can also run all the checking mechanisms locally. To run the tests locally you'll need to run some code beforehand.

python tests/scripts/

This will prepare the filesystem for testing. We do this to prevent the need of downloading very large word embeddings locally and in CI. Fasttext can be 6-7 GB and we don't want to pull such a payload at every CI step. You can also prepare files locally by installing all dependencies via the Makefile.

make install

You can also run all style and type checking mechanisms locally via the Makefile.

make check


We use mkdocs-material for our documentation. To generate the documentation locally you can run the following command:

mkdocs serve

If you're happy with the docs, you can push them to Github (assuming you've gotten the appropriate permissions) via:

mkdocs gh-deploy

This will push the build documentation to the docs branch, which is used for serving the documentation by GitHub pages.