> case_study / modernastro
ModernAstro.com ↗
An AI-powered astrology platform that combines Vedic and Western astrological systems — birth chart analysis, real-time transit predictions, and personalized daily guidance. The calculation engine behind it is where the real complexity lives.
What it does
ModernAstro generates birth charts, calculates planetary transits in real-time, and produces personalized astrological insights powered by AI. Under the surface, it's a calculation engine processing multiple astrological systems — Vedic dashas, Western aspects, house systems, planetary dignities — each with their own rules, and each producing results that feed into the next.
What made it hard
Astrological calculation isn't simple math — it's layered rule systems that interact. A Vedic dasha period depends on the Moon's position at birth, which depends on the ayanamsa correction used, which varies by school of thought. Change one parameter and the entire chart shifts. But a reading generated last month can't retroactively change because you updated a calculation method. You need both: the ability to evolve the engine and the guarantee that past results stay intact.
What we did about it
We separated the calculation engine from the presentation layer entirely. Every chart generated is stamped with the exact ruleset and parameters used. When we add a new house system or refine a transit algorithm, existing charts and readings remain untouched. New logic layers in without rebuilding what's already working. The engine has been evolving continuously without a single full rebuild.
What it taught us
Some software has to evolve for years without starting over. When the domain logic is this deep and this layered, you have to build for change from day one — versioned calculations, clean boundaries between what the system computes and what it shows. We carry this architecture into everything we build where business rules are complex and expected to change.