How to Build an Astrology API from Scratch

Why Build Your Own Astrology API?

Building an astrology API requires deep understanding of astronomical calculations, astrological systems, and API architecture. While you could build from scratch, most developers use existing APIs like Vedika to save months of development time.

Core Components

An astrology API requires these fundamental components:

• Ephemeris Engine - Swiss Ephemeris for planetary positions
• Timezone Database - Historical timezone conversions
• Ayanamsa Calculator - Sidereal zodiac corrections
• House System Calculator - Multiple house systems
• Aspect Calculator - Planetary relationships
• Yoga Detector - Vedic planetary combinations

Step 1: Swiss Ephemeris Setup

Swiss Ephemeris is the gold standard for astronomical calculations:

// Node.js with swisseph library
const swisseph = require('swisseph');

// Initialize ephemeris path
swisseph.swe_set_ephe_path('./ephe');

// Calculate planetary position
function getPlanetPosition(julianDay, planet) {
    const result = swisseph.swe_calc_ut(
        julianDay,
        planet,
        swisseph.SEFLG_SIDEREAL | swisseph.SEFLG_SPEED
    );

    return {
        longitude: result.longitude,
        latitude: result.latitude,
        distance: result.distance,
        speedLong: result.longitudeSpeed
    };
}

Step 2: Julian Day Conversion

All astronomical calculations use Julian Day numbers:

function dateToJulianDay(date, time, timezone) {
    // Convert local time to UTC
    const utcDate = convertToUTC(date, time, timezone);

    // Calculate Julian Day
    const jd = swisseph.swe_julday(
        utcDate.year,
        utcDate.month,
        utcDate.day,
        utcDate.hour + utcDate.minute / 60,
        swisseph.SE_GREG_CAL
    );

    return jd;
}

Step 3: API Endpoint Design

RESTful endpoint structure for astrology APIs:

// Express.js API routes
const express = require('express');
const router = express.Router();

// Birth Chart endpoint
router.post('/v2/astrology/birth-chart', async (req, res) => {
    const { datetime, latitude, longitude, ayanamsa } = req.body;

    // Validate inputs
    if (!datetime || !latitude || !longitude) {
        return res.status(400).json({ error: 'Missing required fields' });
    }

    // Calculate chart
    const chart = await calculateBirthChart({
        datetime,
        latitude,
        longitude,
        ayanamsa: ayanamsa || 'lahiri'
    });

    return res.json(chart);
});

// Panchang endpoint
router.get('/v2/astrology/panchang', async (req, res) => {
    const { date, latitude, longitude } = req.query;
    const panchang = await calculatePanchang(date, latitude, longitude);
    return res.json(panchang);
});

Step 4: Ayanamsa Implementation

Supporting multiple ayanamsa systems:

const AYANAMSA_CODES = {
    'lahiri': swisseph.SE_SIDM_LAHIRI,
    'raman': swisseph.SE_SIDM_RAMAN,
    'krishnamurti': swisseph.SE_SIDM_KRISHNAMURTI,
    'fagan_bradley': swisseph.SE_SIDM_FAGAN_BRADLEY,
    'true_chitra': swisseph.SE_SIDM_TRUE_CITRA
};

function setAyanamsa(ayanamsa) {
    const code = AYANAMSA_CODES[ayanamsa] || swisseph.SE_SIDM_LAHIRI;
    swisseph.swe_set_sid_mode(code, 0, 0);
}

function getAyanamsaValue(julianDay, ayanamsa) {
    setAyanamsa(ayanamsa);
    return swisseph.swe_get_ayanamsa_ut(julianDay);
}

Step 5: House Calculation

function calculateHouses(julianDay, latitude, longitude, houseSystem) {
    const houses = swisseph.swe_houses(
        julianDay,
        latitude,
        longitude,
        houseSystem // 'P' for Placidus, 'W' for Whole Sign, etc.
    );

    return {
        ascendant: houses.ascendant,
        midheaven: houses.mc,
        cusps: houses.house // Array of 12 house cusps
    };
}

Why Use Vedika API Instead?

Building from scratch is educational but impractical for production:

Quick Integration with Vedika

// Instead of building from scratch, use Vedika API
const response = await fetch('https://api.vedika.io/v2/astrology/birth-chart', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
        'x-api-key': 'YOUR_API_KEY'
    },
    body: JSON.stringify({
        datetime: '1990-05-15T14:30:00+05:30',
        latitude: 19.0760,
        longitude: 72.8777
    })
});

const birthChart = await response.json();
console.log(birthChart.planets, birthChart.houses, birthChart.yogas);