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To use Rye you need to have a pyproject.toml based Python project. For this guide you can create one with rye init which will create a new folder with a new project inside:

rye init my-project
cd my-project

The following structure will be created:

├── .git
├── .gitignore
├── .python-version
├── pyproject.toml
└── src
    └── my_project

Good to Know

The init command accepts a lot of options to customize what it generates. Run rye init --help to see all the options available in the version you have installed.

A pyproject.toml is used to store metadata about your project as well as some Rye configuration. Most of Rye's commands will require a pyproject.toml to work. Note that Rye today does not support based projects. Note that when Rye initializes a project it also writes a .python-version file. This file contains the version number of the Python version that should be used for this project. It can be changed by running rye pin. For instance to tell Rye to use Python 3.10:

$ rye pin 3.10

First Sync

Once that is done, you can use rye sync to get the first synchronization. After that, Rye will have created a virtualenv in .venv and written lockfiles into requirements.lock and requirements-dev.lock.

rye sync

The virtualenv that Rye manages is placed in .venv next to your pyproject.toml. The first time you run this you will notice that Rye automatically downloaded and installed a compatible CPython interpreter for you. If you have already another Python installation on your system it will not be used! For more information about this behavior read about toolchains.

You can activate and work with it as normal with one notable exception: the Python installation in it does not contain pip. If you have correctly installed Rye with the shims enabled, after the sync you can run python and you will automatically be operating in that virtualenv, even if it's not enabled. You can validate this by printing out sys.prefix:

python -c "import sys; print(sys.prefix)"

It will print out the full path to the managed virtualenv.

Adding Dependencies

Use the add command to add dependencies to your project.

rye add "flask>=2.0"

Note that after add you need to run sync again to actually install it. If you want to add packages from custom indexes, you have to configure the source first.

Remove a Dependency

Use the remove command to remove a dependency from the project again.

rye remove flask

Working with the Project

To run executables in the context of the virtualenv you can use the run command. For instance if you want to use black you can add and run it like this:

rye add black
rye sync
rye run black

To activate the virtualenv, use the standard methods:

. .venv/bin/activate

To deactivate it again run deactivate: