ǸԹ

Skip to main content
Guidance

Self Assessment technical specifications (2026) for trust and estate returns

Use this technical documentation for trust and estate returns if you’re a software developer working with the Self Assessment online service.

Documents

Request an accessible format.
If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email different.format@hmrc.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Request an accessible format.
If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email different.format@hmrc.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Request an accessible format.
If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email different.format@hmrc.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Request an accessible format.
If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email different.format@hmrc.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Request an accessible format.
If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email different.format@hmrc.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Details

Trust and estate returns technical specifications for software developers working with the Self Assessment online service.

Updates to this page

Published 30 December 2025
Last updated 15 April 2026 show all updates
  1. The attachment 'Trust Special Exclusions version 1.0' has been added.

  2. The attachments 'Validation Rules for Trust and Estate version 1.0.0a', 'Calculate Tax for Trust and Estate version 1.0.0a' and 'Test Case Generator (Tester) Trust and Estate version 1.2.0' have been added.

  3. First published.

Sign up for emails or print this page