GBIF vs inspirehep.net

The Global Biodiversity Information Facility is a keyless REST API for searching species, occurrence, and dataset records aggregated from natural history collections, herbaria, and citizen-science platforms worldwide — its occurrence index alone reports a live count past 3.9 billion records. It's operated by an intergovernmental nonprofit funded by member governments, so querying the API is free; registration is only needed to publish new datasets, not to read existing ones.

INSPIRE-HEP is the high-energy physics community's literature database, covering papers, authors, institutions, and citation graphs going back decades. Its REST API returns JSON records for literature, author, and conference searches and is fully keyless, with no registration or rate-limit tier to opt into.