OpenFisca Core

OpenFisca Core is the engine behind OpenFisca, a microsimulation framework for modeling tax and social benefit systems as code. It supplies the shared rules and computation machinery that country packages, such as OpenFisca-France, build on top of, so a national tax-benefit model does not have to be written from scratch.

The engine runs on Python and relies heavily on NumPy for vectorized calculation across large populations. It installs with pip or conda, and an optional Web API can serve a country package locally so rules, parameters, and situation calculations are reachable over HTTP.

The core package is meant to be added as a dependency of a country package rather than used on its own. It runs locally on your own machine and can be self-hosted as an API, which makes it suited to policy analysis, simulations, and building rules-as-code services.