The mapTax authorityReturns, Payments & Debt
Returns processing & assessment
partly covered · 9 open projects
Receiving and validating returns, automated checks and cross-matching, assessments and corrections.
The honest read
The IRS's Fact Graph, the DGFiP's M-language rules with the Mlang compiler, the Belastingdienst's ALEF rules tool and HMRC's Self Assessment calculation APIs are open assessment engines; Norway's and Hungary's return validation code and the IDB's CACAO receive and check filings. A processing pipeline another authority could adopt whole: nothing open.
A draft: not yet reviewed by a tax specialist.
Start with
Two authorities' own calculation cores: a rules engine for the US code, and the rules of the French engine, with a compiler to run them.
Its 9 projects
| Project | Kind | Jurisdiction | Last update | Stars |
|---|---|---|---|---|
| IRS Fact GraphKnowledge-graph rules engine that models the US Internal Revenue Code, the calculation core of Direct File. | Tax engines | US | Sep 2026 | 419 |
| DGFiP calculette-irThe M-language rules of the DGFiP engine that computes French income tax and the real-estate wealth tax (IFI). | Tax engines | FR | May 2026 | — |
| ALEF (Belastingdienst)Dutch Tax Administration tool for writing executable tax rules in RegelSpraak without programming. | Tax engines | NL | Sep 2026 | 29 |
| CACAO (IDB)IDB web platform for tax administrations to receive, validate, store and analyse taxpayers' accounting data. | Automations | Global | May 2026 | — |
| HMRC Self Assessment calculation APIsHMRC's MTD APIs that trigger and return a Self Assessment calculation, with the liability, BSAS and BISS APIs. | APIs | UK | Oct 2026 | — |
| HMRC View and change income tax (MTD)Frontend where MTD income tax customers view calculations, charges and payments and make changes. | APIs | UK | Oct 2026 | — |
| MlangCompiler for DGFiP's M language, used to compute the income tax of French taxpayers. | Tax engines | FR | Jan 2026 | 203 |
| Skatteetaten skattemeldingenCode and specs for filing the Norwegian tax return: APIs, a validation service, XSDs and a Kotlin calculation. | APIs | NO | Oct 2026 | 47 |
| Skatteetaten trekktabellJava routine from the Norwegian Tax Administration that computes withholding tax from the tax tables.Licence unknown | Tax engines | NO | Dec 2025 | 30 |
Every project here is maintained and serves a tax authority. See the team's projects in the list.