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[DEPRECATED] Web API for OpenFisca
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This package is deprecated

The new OpenFisca Web API is now packaged in OpenFisca-Core. This package isn't maintained anymore.

The aim of this package was to provide OpenFisca information and computations through a web interface, without installing anything locally.

However, after a few years of existence, it appeared:

  • That versioning OpenFisca API and the Core module apart was difficult to maintain
  • That this API endpoints needed to be improved to match users experiences

This final version (8.2.0) is known to be compatible with OpenFisca-Core 23.0.1 and OpenFisca-France 21.9.1.

This package will not be adapted to further versions of OpenFisca-Core.


OpenFisca is a versatile microsimulation free software. This is the source code of the deprecated Web-API module.

The documentation of the project is hosted at

Local install

If you want to run the Web API on your machine, follow these steps. Otherwise, read the documentation to learn how to interact with

Make sure you have Python 2 installed:

python --version
Python 2.7.9

Clone the repository:

git clone
cd openfisca-web-api

Make sure you have the latest version of pip:

pip install --upgrade pip wheel
pip --version
# Should print at least 9.0 at the time we write this doc.

To avoid any dependencies problem we recommend you to use a virtual environment, for example with the tool : pew.

sudo pip install pew

Now create a new virtual environment:

pew new openfisca --python=python2
# Answer "Y" to the question about modifying your shell config file.
# It creates a virtual environment named "openfisca".
# The virtualenv you just created will be automatically activated.
# Later, you'll just have to type "pew workon openfisca" to activate the virtualenv.

Now you have all the requirements to install OpenFisca in your virtual environment.

Install OpenFisca-Web-API (represented by . which is the current directory) and OpenFisca-France in your virtual env:

pip install --editable .[paster] OpenFisca-France
python compile_catalog

If no errors, the Web API is installed in your virtual env. You can now run it with the HTTP server.

Run the HTTP server

paster serve --reload development-france.ini

To check if it's OK, open the following URL in your browser: http://localhost:2000/

2000 is the port number defined in the development-france.ini config file.

You should see this JSON response:

{"apiVersion": 1, "message": "Welcome, this is OpenFisca Web API.", "method": "/"}

Code architecture

Each API endpoint (calculate, simulate, etc.) source code has its own controller (a function responding to a HTTP request) in openfisca_web_api/controllers.

Each controller function consists basically of 3 steps:

  • reading and validating user input (with req.params)
  • doing some computations
  • returning the results in JSON (with wsgihelpers.respond_json)

The configuration of the application is stored in development-<country>.ini files, <country> being either france or tunisia. The configuration is validated once when the application starts. The validation code is in openfisca_web_api/ at the beginning of the load_environment function.

The tests are in openfisca_web_api/tests.

The function make_app in openfisca_web_api/ returns a WSGI application. It is the main entry point of the application and is declared in

All conversion and validation steps are done using the Biryani library.


If you installed OpenFisca-Web-API from Git you can run the unit tests:

make test


See the examples directory.

Deploy in production

See the production-config directory.


The OpenFisca Web API comes with an optional tracker which allows you to measure the usage of the API.

Tracker installation

The tracker is not installed by default. To install it, run:

pip install openfisca_web_api[tracker]  # Or `pip install --editable ".[tracker]"` for an editable installation

Tracker configuration

The tracker is activated when these two variables are set in the .ini configuration file:

  • tracker_url: An URL ending with piwik.php. It defines the Piwik instance that will receive the tracking information.
  • tracker_idsite: An integer. It defines the identifier of the tracked site on your Piwik instance.

For instance, to use the main OpenFisca piwik instance, add these lines to your configuration file:

tracker_url =
tracker_idsite = 4