I'm working on an art project where I want to generate horoscopes based on the current planet positions. I want to makes these somewhat realistic, but I don't know if there is any "planet positions" API, or something for horoscopes that is free. Does anyone know of anything like this? I'm just making a basic web app in html, css, and js if that helps.
programmableweb.com is the first place I stop looking for web APIs covering all sorts of subject matter.
Quick search there shows promising results under "astrology" like
Cerridwen Cerridwen provides planetary data that focuses on our solar system and is suitable for both astronomical and astrological uses. This data includes sunrise times, phases of the moon, the tropical position of the sun, etc. Cerridwen's primary data sources are the Swiss Ephemeris library and its own algorithms, which calculate the phases of the moon and other planetary aspects and events.
Under "planet position" you'll find Ephemeris -
Ephemerides (singular: ephemeris) are tables of values that give the positions of astronomical objects in the sky at a given point in time. Object positions are written in terms of right ascension and declination. Davy Wybiral has created the Ephemeris API as a method of querying NASA's Jet Propulsion Laboratory (JPL) planetary ephemerides, which are generally created to support spacecraft missions to other planets. The Astro-Phys.com Ephemeris service can be accessed using RESTful calls issued in JSON format.