Every G7 government already runs on JSON Schema

TL;DR: Every G7 government (United States, United Kingdom, France, Germany, Italy, Japan, and Canada) runs its digital public infrastructure on JSON Schema. So do nine out of ten of the OECD’s top digital governments in the 2025 ranking. France and Italy already operate national registries that support JSON Schema, and the Netherlands is building one. From December 2026, every EU country will run mandatory digital identity infrastructure on JSON Schema, under eIDAS 2.0.
In 2015, TechCrunch declared that APIs fuel the software that’s eating the world. And as you probably know, the public sector is no exception. For example, the UK’s API Catalogue currently federates 1,791 API entries across UK public-sector publishers. The Netherlands’ national API registry currently lists 302 APIs. The community-run bund.dev portal currently indexes more than 60 German federal APIs. Italy publishes its API catalogue, which currently carries 14,672 e-services across 9,398 adhering public and private entities.
In terms of scale, Denmark’s Central Data Distribution Platform API “processes more than 70 million calls daily, and handles a daily data volume of 2.5 terabytes”. The United States data API is “used by 25 agencies for over 450 APIs”. South Korea’s data API offers “87,000 public data sets and 11,000 open APIs”. The UK Government Digital Service publishes an API exposing more than 8.4 million UK legal documents. Beyond datasets, the GOV.UK Notify API sent 12 billion messages by February 2026 on behalf of more than 11,000 public-sector services. Estonia’s X-Road API exchange links “more than 1,000 inter-connected databases covering some 1,700 services” and answers “more than 50 million enquiries every month”. In the US, the Law Enforcement Information eXchange (LInX) connects “thousands of law enforcement agencies” sharing “1.8 billion records amongst each other”.
The AI wave is only reinforcing the fact that the public sector runs on APIs. As Kin Lane puts it, “MCP is an API”, and adoption within the public sector has already started. For example, consider the US GovInfo MCP, the US Census Bureau MCP, France’s data.gouv.fr MCP, Japan’s Digital Agency jgrants-mcp-server, and the UK Government Digital Service’s Parliament MCP.
Like the rest of the industry, the public sector has also settled on OpenAPI as the format for describing APIs in a machine-human readable way.
Many governments have explicitly written “use OpenAPI” into national API standards documents. For example, Canada mandates OpenAPI for all federal RESTful APIs. The United Kingdom’s Open Standards Board states that “Describing RESTful APIs with OpenAPI 3 is recommended by the government Open Standards Board”. Italy goes a step further: every API published on the National Digital Data Platform (PDND) is validated by “running the OAS Checker with the Italian Guidelines Full profile and obtaining 0 errors”. Japan’s Digital Agency states that “Government agencies are expected to adopt OAS […] to make development more efficient”.
The following table offers a more exhaustive summary:
Even beyond mandates, the European Commission found that “OAS was used by almost half of all reviewed API portals” across the European public-sector portals it surveyed.
The picture extends across borders too. X-Road, an open-source data-exchange platform that uses OpenAPI to describe its REST services, was jointly founded by Estonia, Finland, and Iceland through the Nordic Institute for Interoperability Solutions (NIIS). Estonia operates it domestically as X-tee and Finland as the Suomi.fi data exchange layer. X-Road has been adopted as the national data exchange in Cambodia (as CamDX), Japan (via PlanetCross at Nichigas), El Salvador, and Kyrgyzstan (as Tunduk).
We have established that public-sector API adoption runs through OpenAPI and MCP. What is easy to miss, but more consequential, is that both share the same substrate: JSON Schema.
More precisely, OpenAPI builds on top of JSON Schema. While OpenAPI offers syntax to declare endpoints and top-level metadata, what you use to actually describe request bodies, responses, headers, and query parameters is JSON Schema embedded within OpenAPI. In fact, we previously found that “in 76% of modern OpenAPI specs, JSON Schema dominates the specification”. So when governments work on OpenAPI at the scale we have just seen, they are, in the large majority, working on JSON Schema. A government OpenAPI mandate is, on closer reading, a JSON Schema mandate.
The same principle holds for MCP. The official specification is built on JSON Schema 2020-12, and every MCP tool exposes its inputs as a JSON Schema object. The pattern reaches well beyond MCP. As we previously argued, “the only schema language AI speaks is JSON Schema”. Every major LLM provider’s tool-calling interface, every AI product, and every agent framework has converged on the same substrate. As Charlie Holland puts it, JSON Schema has become “the interface definition language for AI tools”. A government MCP server is, on closer reading, a JSON Schema deployment.
We are not the only ones making this observation. When Kin Lane inventoried the API specifications stewarded by the Linux Foundation, he concluded that JSON Schema is the connective tissue across the whole catalogue: OpenAPI, AsyncAPI, CloudEvents, and others all build on it, and “JSON Schema is the substrate the other specifications are built on top of”.
Taken together, public-sector use of OpenAPI and MCP rank among the largest JSON Schema deployments in the world.
If OpenAPI and MCP are both about JSON Schema, it is no surprise that governments are starting to treat schemas as their own layer, separable from any particular API specification and reusable across OpenAPI, MCP, and potentially other future consumers. They operate their schemas as standalone national assets.
France runs schema.data.gouv.fr as a national multi-format schema registry. Among its JSON Schemas, the public procurement format mainta