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Installation

ddi-l requires Python 3.11 or newer and is available on PyPI.

Install from PyPI

Use this unless you want to change ddi-l itself.

pip install ddi-l
ddi --help

poetry add ddi-l
poetry run ddi --help

Verify the installation

  • ddi --help confirms the CLI entry point is on your PATH.
  • python -c "import ddi_l; print(ddi_l.__version__)" prints the installed version.

Optional dependencies

Need Command What it unlocks
Accelerated XML parsing pip install 'ddi-l[full]' Enables the lxml backend: faster parsing, and near-instant validation of valid documents.
HTTP API pip install 'ddi-l[server]' Adds the Litestar service behind ddi serve; see HTTP API.

Schemas are already included

The DDI 3.1, 3.2, and 3.3 XML Schemas ship inside the package, so doc.validate() and ddi validate work offline with no extra download and no network access.

Install from source

Developers contributing to ddi-l should install from a local checkout:

git clone https://github.com/pbisson44/ddi-l.git
cd ddi-l
pip install -e .

Install the development toolchain. The project is managed with uv, and uv.lock pins every dependency version:

uv sync --group dev              # Runtime + development dependencies
uv sync --group dev --extra full # ...plus the optional lxml backend

Note that full is an extra, not a dependency group: --group full fails.

With plain pip instead (pip 25.1 or later reads dependency groups):

pip install -e '.[full]' --group dev

For documentation work (docs is a dependency group, not an extra):

uv sync --group docs
# or
pip install -e . --group docs

Verify with a quick smoke test

import ddi_l as ddi

doc = ddi.new_study(title="Test", agency="example.org")
doc.add_question(text="Does it work?")
print(f"Questions: {len(doc.questions)}")  # -> 1

For more details, see the user guide or the contributor guide.