IRS Modernized e-File (MeF) API
Application-to-Application (A2A) system enabling authorized software developers and transmitters to electronically submit tax returns directly to the IRS. Supports individual and business tax forms including Form 2290, Form 720, Form 8849, and more. Requires TLS 1.2 or higher. Technical specifications available in IRS Publication 4164. Current WSDL version is R10.9 for tax year 2025/processing year 2026.