Legal
6 distinct extensions were invented to do this job. Each one is a provider deciding OpenAPI would not carry something and building their own way through. Where a job has many names and few uses each, nobody won — the problem was solved privately, over and over.
6 extensions
62 occurrences
3 vendor-named
The extensions
| Extension | What it appears to do | Uses | Providers |
|---|---|---|---|
| x-license-terms | `x-license-terms` appears on schema objects and properties. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with legal — this is inferred from where t | 53 | 1 |
|
x-ms-legal-hold
vendor |
`x-ms-legal-hold` appears on header objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-ms-` namespace, so its meaning is defined by ms to | 4 | 1 |
|
x-amz-object-lock-legal-hold
vendor |
`x-amz-object-lock-legal-hold` appears on header objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-amz-` namespace, so its meaning is de | 2 | 1 |
| x-copyright | `x-copyright` appears in the info block. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `© Hang 2023`. Consistent with legal — this is inferred | 1 | 1 |
| x-doc-license | `x-doc-license` appears in the info block. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with legal — this is inferred from where the key appears an | 1 | 1 |
|
x-ms-has-legal-hold
vendor |
`x-ms-has-legal-hold` appears on header objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. It sits in the `x-ms-` namespace, so its meaning is defined by m | 1 | 1 |
Work with this as data
Every extension here is available over the APIs.io API and to AI agents over MCP. OpenAPI Extensions is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.
MCP server
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
Tools for openapi extensions
3 MCP tools reach this
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=legal&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/legal"Discovery needs no key. Ratings and market analysis are Pro.