IRS Open-Sources Direct File: A Free, Interview-Based Tax Filing System

The IRS has open-sourced Direct File, a free online tax filing service. It uses an interview-based approach, works on various devices (mobile, desktop, etc.), and supports English and Spanish. Direct File translates tax law into plain-language questions, generating standard tax forms that are submitted to the IRS. At its core is the Fact Graph, a Scala-based knowledge graph handling incomplete information. Direct File also facilitates state and local tax filing by allowing users to import their federal return data into third-party tools. Developed in-house by the IRS with support from USDS, GSA, and other partners, some code was excluded due to privacy and security concerns.