Verifiable by construction
Astrology is math. We make the math transparent: Swiss Ephemeris precision, deterministic outputs, and 799 automated checks that run on every deploy.
1 · Ephemeris precision at the edge
Planetary positions come from the Swiss Ephemeris — the same reference implementation used by professional astrologers worldwide — compiled to WebAssembly and running inside the edge worker (Moshier fallback for deep-history dates). Longitudes are computed to arc-second accuracy, sidereal positions use LAHIRI / RAMAN / KP ayanamsas, and house cusps are exact across Placidus, Whole Sign, Koch, Equal, Campanus and Regiomontanus.
2 · Deterministic — same input, same output
The engine is a pure function: the same birth moment returns the same chart, every time, on every region. No randomness, no model drift, no version skew. Cache your calls and diff the output — it will not change.
3 · Rules with receipts
Every prediction is a classical rule evaluated against real positions — Vedic (Shadbala, Ashtakavarga, Arudha, Dasha), Western (lots, Firdaria, zodiacal releasing), Chinese (Day Master strength, hidden stems). When a rule fires, the response says which rule, with its source and weight. The engine never invents a reason.
4 · 799 automated checks
A test matrix of 799 assertions covers ephemeris positions, house cusps, panchang limbs, dasha timelines, aspect math, rule evaluation and API contracts. Every deploy runs the full suite — a regression in any tradition fails the build.