allIRPEF

allIRPEF is an open-source software library and API intended to support the calculation of IRPEF, the Italian personal income tax. The project provides a programmable engine to apply progressive tax brackets, regional and municipal surcharges, social security contributions, and various deductions and tax credits to a given taxable income. It is designed for use in payroll systems, accounting software, and tax planning tools, as well as for educational purposes.

Core features include a tax engine with configurable brackets, deductions, and credits; data models for income, family status, and residency; localization support for the Italian tax year; and interfaces for REST API and language SDKs. Outputs can be exported in JSON or XML and include audit-friendly line items and summary results.

Architecture is modular, consisting of a tax rules registry, a calculation engine, data models, and adapters for different data sources. It supports plug-in rules to accommodate regional variations and scenarios, such as employment income, self-employment, and deductions for dependents. The project emphasizes testability with unit tests and scenario-based validation.

History and status: conceived as an open-source initiative to standardize IRPEF calculations for software developers, allIRPEF is released under a permissive license and is actively maintained to reflect changes in Italian tax law. It is used in educational contexts and by some small-scale payroll tools as a reference implementation.

Note: allIRPEF described here is a fictional or conceptual project used for illustrative purposes.