Interoperability refers to the ability of credentials from different issuers to function seamlessly across various systems, industries, and jurisdictions. It means a driver's license issued in California can be verified at a TSA checkpoint in New York, or a diploma from a European university can be trusted by a U.S. employer, without requiring custom integrations or manual workarounds.
Why does interoperability matter?
Today, credentials are often locked within separate silos. Universities issue diplomas. DMVs issue driver's licenses. Insurance companies issue cards. Each system solves its own requirements, but without shared technical frameworks, verifying credentials across systems becomes inefficient or impossible.
True interoperability allows people to combine different credentials and present only what's necessary in each context. When applying for a job, someone should be able to prove both residency and degree attainment from a single source, without revealing sensitive details such as their full legal name or exact university affiliation.
How do standards enable interoperability?
Interoperability requires shared rules. When issuers, holders, and wallets align with the same technical standards, credentials become portable and consistent across all parties. The outcome is similar to how web browsers work: regardless of the country or provider, shared internet protocols ensure that websites load and function properly.
Key standards bodies include the World Wide Web Consortium (W3C), the International Organization for Standardization (ISO), and the Internet Engineering Task Force (IETF). Their specifications, including W3C Verifiable Credentials, ISO 18013-5 for mDLs, and SD-JWT for enterprise contexts, provide the technical frameworks that enable interoperability.
Real-world examples
Interoperability enables practical scenarios across contexts. A mobile ID issued in one state is recognized at airports across the nation. A digital diploma is instantly verified by an employer anywhere in the world. A patient record issued in one healthcare system can be read securely by another. A bartender can verify age regardless of which state issued the credential.
The Department of Homeland Security, NIST, and TSA work with states and standards bodies to define interoperable frameworks. AAMVA's Digital Trust Service enables cross-state mDL verification. ISO/IEC 18013-5 ensures that mDLs from any conforming state can be verified by any conforming reader.
What is the role of open source?
Even when standards exist, variations in implementation can create friction. Two solutions may both follow a specification but remain incompatible if built differently. Open-source libraries address this by providing consistent codebases that implementers can adopt, ensuring interoperability is not left to chance.
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