How to migrate from requirements.txt to pyproject.toml with uv

1. Create a pyproject.toml file

$ uv init --bare

This creates a minimal pyproject.toml without sample code. If the project already has a pyproject.toml (from a tool like setuptools), skip this step.

2. Import your existing requirements

$ uv add -r requirements.txt

This command:

• Reads dependencies from requirements.txt
• Adds them to pyproject.toml
• Creates a lockfile (uv.lock) that pins exact versions for reproducible installs
• Installs dependencies in the project’s virtual environment

3. Import development requirements

If you have a separate requirements-dev.txt (or requirements-test.txt, etc.):

$ uv add --dev -r requirements-dev.txt

This adds them as development dependencies, which are installed during development but excluded from production builds.

Verify that all dependencies were imported correctly:

$ uv pip freeze

4. Remove the old requirements files

Once you’ve confirmed the migration, remove the old files:

$ rm requirements.txt requirements-dev.txt

5. Manage dependencies with uv going forward

# Add new runtime dependency
$ uv add requests

# Add development dependency
$ uv add --dev pytest

# Remove dependency
$ uv remove requests

# Install all dependencies from lockfile
$ uv sync