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The mapTax authorityPolicy, Legislation & Revenue Analysis
Reform costing & microsimulation
covered · 33 open projects
Costing proposed changes, revenue and distributional impact, tax-benefit models of the whole population.
Start with
Both are maintained microsimulations with documentation and tests; OpenFisca France does the same for France.
Its 33 projects
| Project | Kind | Jurisdiction | Last update | Stars |
|---|---|---|---|---|
| PolicyEngine USRules engine and microsimulation model of the US tax-benefit system. | Tax engines | US | Oct 2026 | 164 |
| Tax-CalculatorFederal income and payroll tax microsimulation from the Policy Simulation Library. | Tax engines | US | Oct 2026 | 311 |
| Cost-of-Capital-CalculatorCalculates the cost of capital and effective tax rates on new investment. | Tax engines | US | Apr 2026 | — |
| EUROMODThe EU tax-benefit microsimulation model, maintained by the Joint Research Centre. | Tax engines | EU | — | — |
| GETTSIMThe German Taxes and Transfers Simulator: a microsimulation model of German taxes and benefits. | Tax engines | DE | Sep 2026 | 72 |
| OG-CoreOverlapping-generations model framework for evaluating the economic effects of fiscal policy. | Tax engines | Global · US | Oct 2026 | 85 |
| OpenFiscaRules-as-code framework: legislation written in Python, served as a web API. | Tax engines | FR · Global | — | — |
| OpenFisca ArgentinaEarly OpenFisca model of Argentina's tax and benefit system. | Tax engines | AR | May 2026 | — |
| OpenFisca AustriaEarly OpenFisca model of Austria's tax and benefit system. | Tax engines | AT | Jul 2026 | — |
| OpenFisca CzechiaEarly OpenFisca model of the Czech tax and benefit system. | Tax engines | CZ | Jul 2026 | — |
| OpenFisca FranceThe French tax and benefit system, written as OpenFisca rules. | Tax engines | FR | Oct 2026 | 312 |
| OpenFisca France EntreprisesMicrosimulation of French firms' taxes and subsidies around the carbon tax, built on OpenFisca. | Tax engines | FR | Sep 2026 | — |
| OpenFisca France indirect taxationOpenFisca model of French indirect taxes. | Tax engines | FR | Mar 2026 | — |
| OpenFisca IndiaEarly OpenFisca model of India's tax and benefit system. | Tax engines | IN | Aug 2026 | — |
| OpenFisca JapanJapan's tax and benefit rules as an OpenFisca API, with a web app on top. | Tax engines | JP | Aug 2026 | — |
| OpenFisca KoreaEarly OpenFisca model of South Korea's tax and benefit rules. | Tax engines | KR | Feb 2026 | — |
| OpenFisca NLEarly OpenFisca model of Dutch tax and benefit rules. | Tax engines | NL | Nov 2025 | — |
| OpenFisca Nouvelle-CalédonieNew Caledonia's tax and benefit system for OpenFisca. | Tax engines | NC | May 2026 | — |
| OpenFisca ParaguayParaguay's tax and benefit system for OpenFisca. | Tax engines | PY | Feb 2026 | — |
| OpenFisca Polynésie françaiseFrench Polynesia's tax system as OpenFisca rules-as-code. | Tax engines | PF | Jun 2026 | — |
| OpenFisca SenegalSenegal's tax and benefit system for OpenFisca. | Tax engines | SN | Jan 2026 | — |
| OpenFisca TunisiaTunisia's tax and benefit system for OpenFisca.Licence unknown | Tax engines | TN | Oct 2026 | 22 |
| PolicyEngineOpen tax-benefit models with a public app for scoring policy reforms. | Tax engines | US · UK | — | — |
| PolicyEngine APIREST API that computes the impact of tax and benefit policies with the PolicyEngine models. | APIs | Global | Oct 2026 | — |
| PolicyEngine AustraliaMicrosimulation model of Australia's tax and benefit system.Licence unknown | Tax engines | AU | Apr 2026 | — |
| PolicyEngine CanadaModel of Canada's tax and benefit system, built on PolicyEngine Core. | Tax engines | CA | Apr 2026 | — |
| PolicyEngine CoreCore microsimulation engine for PolicyEngine models, forked from OpenFisca Core. | Tax engines | Global | Oct 2026 | — |
| PolicyEngine TAXSIMTAXSIM emulator built on PolicyEngine's US federal and state tax calculator. | Tax engines | US | Sep 2026 | 18 |
| PolicyEngine UKOpen-source static tax-benefit microsimulation model for the UK. | Tax engines | UK | Oct 2026 | 50 |
| policyengine.pyPolicyEngine's Python package that brings the country models, analysis and charts together. | Tax engines | Global | Sep 2026 | — |
| Taxsim.jlJulia interface to TAXSIM, the NBER's calculator for US federal and state income taxes. | APIs | US | Sep 2026 | — |
| UK land value taxDashboard that models replacing UK council tax with a land value tax.Licence unknown | Tax engines | UK | May 2026 | — |
| UK VATLabToolkit for modelling UK VAT policy.Licence unknown | Tax engines | UK | Jun 2026 | — |
Every project here is maintained and serves a tax authority. See the team's projects in the list.
On Learn
- Run a tax policy simulationHow-to guide
- Rules as codeGlossary term
- Tax engineGlossary term