health-reference

Twenty-three services covering drugs, clinical trials, medical coding, providers, nutrition and molecular reference data, all behind one HTTP surface at https://fittings.sh and all sourced from US federal registries. The live list, with prices and full schemas, is at https://fittings.sh/catalog?category=Health%20and%20medicine. Browsing it, searching it and reading any schema cost nothing.

When to reach for this

The dividing line is not "medical question" versus "not medical question". It is whether the answer is knowledge or a record.