HMRC published a strategic framework on 26 March 2026 outlining plans to strengthen standards for third-party software that integrates with UK tax and customs systems, with implementation expected between 2026 and 2027.
The strengthened standards will apply to all third-party software providers whose products integrate with HMRC's Application Programming Interface (API) services, covering both JSON RESTful APIs through the HMRC Developer Hub and XML APIs maintained for specific services. Software that does not integrate with HMRC systems using these APIs remains outside the scope.
Framework Structure
The framework establishes five core themes for strengthened standards. Product integrity requirements will emphasise pre-deployment assurance, including demonstrable accuracy of tax and customs calculations and operational resilience testing. Supporting correct outcomes standards will focus on in-product prompts, alignment with HMRC guidance, and design approaches that reduce user error and cognitive burden.
Data accountability measures will require retention of appropriate transactional data, provision of HMRC access for audit purposes, and maintenance of clear audit trails. Error management standards will address early identification and resolution of tax-related errors, timely reporting of significant issues, and prompt remediation to minimise customer harm.
Misuse and fraud prevention standards will target risks from software enabling non-compliant behaviour, including identification of misuse, design features reducing large-scale abuse opportunities, and support for HMRC's compliance efforts.
Implementation and Governance
HMRC will distinguish between provider-level standards focusing on organisational responsibilities and product-level standards addressing how individual products interact with HMRC systems. The authority will apply standards proportionately and risk-based, building on existing controls including Developer Hub Terms of Use compliance requirements.
The planned timeline includes co-development and stakeholder engagement from April to autumn 2026, testing with software providers from autumn 2026 to early 2027, and evaluation and refinement through mid to late 2027. HMRC will provide clear transition periods to support implementation across the diverse software market.
Context
The initiative responds to increasing reliance on third-party software, with approximately 90% of tax returns submitted via third-party software in 2024-25. The framework builds on existing requirements while addressing areas not currently covered, supporting HMRC's digital-first transformation and broader intermediary approach to tax system integrity.
