The Financial Data Exchange Releases First Major Update to FDX API, Makes Fourth Version Available


The FDX API 4.0 introduces critical improvements to tax applications and brings full compliance with REST conventions, other international standards
Posted on 3/19/2020

RESTON, Va. – March 19, 2020 – The Financial Data Exchange (FDX) has released the fourth version of the FDX API, an updated standard designed to enhance interoperability and performance for the full range of supported use cases. The previous versions of the common, interoperable and royalty-free standard, which is developed by a consortium representative of the entire financial services ecosystem, were rapidly adopted by the industry and protect nearly 12 million U.S. consumers.

FDX 4.0 is the first major update to the industry-leading standard, previously known as Durable Data API 2.1 or FDX API 3.0, and took approximately nine months to develop. The new version completely overhauls tax treatment within the specification and introduces 58 new tax entities designed to enhance interoperability and increase the number of supported use cases. An entirely new suite of resource endpoints (APIs) is coupled with these entities to drive adoption by tax software and tax preparation companies, as well as tax data suppliers and tax data aggregators.

“As we continue to enhance our standard over the next few years, we will always keep a focus on our original charter: to provide consumers with secure interoperability in line with the principles of control, access, transparency, traceability and security,” Cardinal said.

Other updates to the API include full compliance with REST conventions, the introduction of new elements that facilitate the entry of personal information, as well as support for the ITU-T’s E.164 recommendation on the treatment of international phone numbers. FDX 4.0 is released with a companion document “Control Considerations for Consumer Financial Account Aggregation Services 3.1” that outlines a security reference architecture for use by the implementers of FDX API, and now references the FIDO 1.2 UAF and U2F frameworks and CIBA 1.0.

“By dramatically improving tax applications within the standard, our members, and those implementing the FDX API, will now be able to offer their customers a more complete, expanded picture of their personal finances,“ said Don Cardinal, Managing Director of the Financial Data Exchange. “This will enable consumers to have greater control over their savings, investments, digital payments and tax history.”

For the next iteration of the API standard, FDX will concentrate on developing use case-driven data scopes in line with data minimization principles, as well as increased transparency and security features for consumers. These efforts will be coupled with the release of user experience guidelines, and a certification program that will create a technical compliance-framework for FDX implementations.

For more information on these principles and how they should be put into practice, download the new FDX White Paper, available here. To access the specification and to join, visit

About FDX
Financial Data Exchange, LLC is a non-profit organization dedicated to unifying the financial industry around a common, interoperable, royalty-free standard for secure and convenient consumer and business access to their financial data. FDX empowers consumers through its commitment to the development, growth and industry-wide adoption of the FDX API, according to the principles of control, access, transparency, traceability and security. Membership is open to financial institutions, fintech companies, consumer advocacy groups, and other industry participants. FDX is an independent subsidiary of FS-ISAC. For more information and to join, visit