Collection

Self Assessment online service for software developers

Support and technical specifications for software developers working with the Self Assessment online service.

• From: HM Revenue & Customs
• Published: 1 January 2014
• Last updated: 20 January 2015 — See all updates

For support on current and archived specifications contact the software developers support team by email: SDSTeam@hmrc.gov.uk.

Generic technical specifications

• Local Test Service and LTS update manager
  • 15 January 2026
  • Guidance
• Self Assessment technical specifications for software developers
  • 20 January 2023
  • Guidance
• Self Assessment identical returns: support for software developers
  • 1 January 2014
  • Guidance

Individual returns

• Self Assessment technical specifications (2026) for individual returns
  • 19 May 2026
  • Guidance
• Self Assessment technical specifications (2025) for individual returns
  • 15 July 2025
  • Guidance

Partnership returns

• Self Assessment technical specifications (2026) for partnership returns
  • 30 March 2026
  • Guidance
• Self Assessment technical specifications (2025) for partnership returns
  • 21 May 2025
  • Guidance

Trust and estate returns

• Self Assessment technical specifications (2026) for trust and estate returns
  • 15 April 2026
  • Guidance
• Self Assessment technical specifications (2025) for trust and estate returns
  • 15 July 2025
  • Guidance

• Last updated: 20 January 2015
  Show all updates

  1. 20 January 2015

     Self Assessment technical support 2015 published.

  2. 1 January 2014

     First published.