Every moment, the planets trace paths that ancient astronomers spent lifetimes cataloging by hand. With one API call, you can resolve those positions to fractions of an arcsecond — the same precision that took Tycho Brahe decades of naked-eye observation to approach.
A natal chart renderer. A transit alert system that watches the sky and pings you when Saturn crosses your ascendant. An educational app where students drag a slider through centuries and watch the planets dance. A generative art piece driven by the actual geometry of the solar system right now.
The Swiss Ephemeris covers 13,000 BCE to 16,800 CE for planets and the Moon. That’s every conjunction, every station and retrograde loop for the entirety of recorded human history — and well beyond it. The calculations that once required a room full of ephemeris tables now resolve in under a millisecond at the edge.
The Swiss Ephemeris compiled to WebAssembly, running on Cloudflare’s global network. No servers to manage, no cold starts to worry about.
Swiss Ephemeris data spanning nearly 30,000 years. The same engine trusted by professional astronomers and astrologers worldwide.
Runs on Cloudflare Workers across 300+ locations. Typical response times under 50 ms from anywhere on Earth.
All 22 house systems. 47 ayanamsha methods. 1,500+ fixed stars. Equatorial and ecliptic coordinates. Topocentric corrections.
500 free requests every month. After that, $0.01 per request with prepaid credits. No subscriptions, no surprises.
From raw planetary positions to full natal charts, synastry, and progressions. Most endpoints cost 1–2 credits — relationship charts cost 3.
/v1/positionsPlanetary longitude, latitude, distance, speed/v1/housesHouse cusps and angles for any location/v1/chartCombined positions and houses in one call/v1/starsFixed star positions by name or catalog/v1/ayanamshaSidereal correction for any ayanamsha system/v1/delta-tDelta T (TT − UT1) for any date/v1/sidereal-timeGreenwich sidereal time/v1/eclipses/solarSolar eclipse search with magnitude and contacts/v1/eclipses/lunarLunar eclipse search with phase timing/v1/heliacalHeliacal rising and setting of planets/v1/ingressesSign ingresses and longitude crossings/v1/natal-chartFull natal chart with aspects, dignities, and house placements/v1/aspectsAspects and parallels between celestial bodies/v1/dignitiesEssential dignities, scores, and dispositorship chains/v1/synastryTwo-chart comparison with inter-chart aspects/v1/compositeMidpoint composite chart from two natal charts/v1/davisonDavison relationship chart at the time-space midpoint/v1/progressedSecondary progressed chart (day-for-a-year)/v1/draconicDraconic chart with North Node at 0° Aries/v1/returnsPlanetary return charts (Sun, Moon, or other body at natal longitude)/v1/lotsArabic Parts/Lots with day/night reversal/v1/solar-proximityCazimi, combust, under the beams, or free/v1/void-of-courseIs the Moon void of course?/v1/planetary-hours24 planetary hours in Chaldean order/v1/batchExecute up to 50 requests in a single callStart free. Pay only when you need more.
Free Tier
$0
per month
Prepaid Credits
$0.01
per request
Free tier resets monthly. Paid credits stack on top of the free allowance. Full pricing details
Agent-Friendly
Morphemeris is designed to be discovered and used by AI agents. OpenAPI spec, llms.txt, structured error messages with suggestions, and an MCP server — so your agent can integrate astronomical data without reading a single doc page.
Sign up, create an API key, and make your first request. No credit card, no approval process, no waiting.