HM Revenue & Customs published its Strategic Approach to External Integration on 26 March 2026, setting out how it will work with software providers to enhance third-party integration with HMRC systems through Application Programming Interfaces (APIs).
API Innovation Portal
The strategy establishes an 'API Innovation Portal' providing a transparent mechanism for industry proposals on external integration, data access, and integration improvements. The portal will offer real-time visibility of requests and progress, featuring a searchable API catalogue organised by product and function with standardised processes for handling software provider requests for new data or functionality.
HMRC will strengthen minimum service standards for software integrating via the HMRC Developer Hub, focusing on tax accuracy, customer protection, and prevention of harm. These standards will apply to all integrated products accessing HMRC systems.
Integration Methods
The document confirms that APIs remain HMRC's preferred integration mechanism, ensuring security, consistency and high-quality customer experience. Integration methods attempting to automate or replicate HMRC web services, including screen scraping or automated browser interactions, are explicitly not supported as HMRC aligns with wider credential protection work.
HMRC received over 5.4 billion API requests in 2024-25, up from 4.1 billion in 2023-24, with approximately 90% of digital returns submitted via third-party software. The number of third-party providers has grown from around 600 to almost 3,000, with over 1,000 providers in VAT services alone.
Implementation Timeline
HMRC will publish a detailed delivery plan by Spring 2027 as part of its broader Strategic Approach to Third Party Software, outlining upcoming improvements, new APIs, and migration expectations. Further information on the API Innovation Portal functionality and developer engagement processes will follow, alongside clarified guidance on supported versus unsupported access methods.
Context
This approach builds on HMRC's 2015 API Strategy and supports delivery of the Transformation Roadmap through enhanced external integration. The strategy reflects the maturation of the tax software market and growing demand for increased data sharing from software providers supporting UK economic growth, while maintaining security and compliance standards across the tax and customs system.
