arcsecond.io vs Newton

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.

Newton is a keyless calculator API deployed as a Vercel serverless function: the operation (simplify, factor, derive, integrate, and more) and expression are both encoded directly in the URL path, and it answers with a small JSON object containing the result. It's a solo open-source project (aunyks/newton-api) rather than a commercial service, so there's no pricing tier or rate limit to opt into.