Build a birth chart app with APlicious Astrology API

Birth chart apps are one of the highest-engagement consumer products you can build. Co-Star has 20 million users. The APlicious Astrology namespace gives you everything you need — natal charts, daily transits, compatibility — from three GET requests and one API key.

What we're building

A birth chart micro-SaaS called ChartMind:

Enter date, time, and place of birth → get a full natal chart
See today's planetary transits and how they hit your natal planets
Enter a partner's birth data → get a synastry compatibility score

Business model: $9/month, 600 subscribers = $5,400 MRR. Build time: ~2 weeks. API cost: $0 extra (included in your APlicious plan).

Step 1 — Natal chart

The /astrology/natal-chart endpoint takes a UTC datetime plus latitude/longitude and returns all 10 planet positions, house cusps, and ascendant:

const res = await fetch(
  'https://aplicious.com/api/v1/astrology/natal-chart' +
  '?datetime=1990-01-01T12:00:00Z&lat=28.6139&lon=77.2090',
  { headers: { 'X-API-Key': process.env.APLICIOUS_KEY } }
);
const { data } = await res.json();
// data.sun   → { sign: 'Capricorn', degree: 10.5, house: 4, retrograde: false }
// data.moon  → { sign: 'Aries',     degree: 22.3, house: 7, retrograde: false }
// data.ascendant → 'Libra'

Step 2 — Daily transits

/astrology/transits shows what the current planets are doing to your natal chart — which natal planets are being aspected and by what transit planet:

const today = new Date().toISOString();
const res = await fetch(
  'https://aplicious.com/api/v1/astrology/transits' +
  `?natal_datetime=1990-01-01T12:00:00Z&transit_datetime=${today}`,
  { headers: { 'X-API-Key': process.env.APLICIOUS_KEY } }
);
const { data } = await res.json();
// data.transits → [
//   { transit_planet: 'Saturn', aspect: 'square', natal_planet: 'Sun', orb: 1.2 },
//   { transit_planet: 'Jupiter', aspect: 'trine', natal_planet: 'Moon', orb: 0.8 }
// ]

Step 3 — Compatibility

/astrology/synastry cross-aspects two charts and returns a structured compatibility analysis:

const res = await fetch(
  'https://aplicious.com/api/v1/astrology/synastry' +
  '?datetime1=1990-01-01T12:00:00Z&datetime2=1995-06-15T12:00:00Z',
  { headers: { 'X-API-Key': process.env.APLICIOUS_KEY } }
);
const { data } = await res.json();
// data.aspects → [ { planet1: 'Sun', planet2: 'Moon', aspect: 'conjunction', orb: 2.1 } ]
// data.score   → 78   (0–100 compatibility score)

Pricing and revenue math

At $9/month you need 112 subscribers to clear $1,000 MRR — achievable within 60 days of launch with a focused Reddit + TikTok strategy targeting astrology communities. The API cost stays flat regardless of usage volume (it's your APlicious plan quota, not a per-call fee).

Full business plan with five product ideas and a revenue calculator at aplicious.com/build/astrology. Live API docs with Try-It at aplicious.com/docs.