GBIF vs SHARE

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.

SHARE (now internally rebranded "trove", version 26.0.0 as of this check) is the Center for Open Science's free aggregator of metadata about research and scholarly activity, pulling in tens of millions of records from sources like CrossRef and OSF and re-indexing them for keyless search. Its v2 API exposes an Elasticsearch-backed search endpoint plus RSS and Atom feeds, all reachable with no registration.