arcsecond.io vs SHARE

Arcsecond.io is the cloud API behind Arcsecond.local, a multi-user platform observatories run to manage telescopes, night logs, and data packages, but it still exposes the project's original public astronomy-lookup endpoints for object coordinates and exoplanets. Those endpoints are keyless and return live-synced records — /exoplanets/ pulls current rows from the NASA Exoplanet Archive. Paid tiers apply only to running a private observatory instance; the public data-lookup endpoints stay free.

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.