Composite Chart

Endpoint POST https://starsapi.com/api/v3/western/compatibility/composite

Overview

Generates a composite midpoint chart — the midpoint of each pair of corresponding planets from both natal charts. The composite chart represents the relationship itself as a third entity, distinct from either individual.

Composite Sun = midpoint of Person 1’s Sun and Person 2’s Sun, and so on for all planets, ASC, and MC. The resulting chart is read like a natal chart but describes the dynamics and purpose of the relationship.

Authentication

Method	Example
Header (recommended)	`X-Api-Key: am_live_xxxxxxxxxxxx`
Bearer	`Authorization: Bearer am_live_xxxxxxxxxxxx`

Request body

Same person1/person2 nested structure as synastry.

Field	Type	Required	Description
`person1.*`		Yes	Person 1 birth data (year, month, day, hour, minute, second, latitude, longitude, timezone).
`person2.*`		Yes	Person 2 birth data.
`house_system`	string	No	Default `placidus`.
`node_type`	string	No	Default `true`.

Response shape

Returns a full chart structure — same format as a natal chart but with midpoint-derived positions.

Field	Description
`planets`	Composite planet positions (midpoints of both charts).
`ascendant`	Composite Ascendant.
`midheaven`	Composite MC.
`house_cusps`	Composite house cusps.
`house_system`	House system used.

Errors

HTTP	Code	Cause
400	`MISSING_FIELD`	Required field absent.
500	`EPHEMERIS_ERROR`	Computation failed.

# Replace YOUR_API_KEY with the key from your dashboard
curl -X POST "https://starsapi.com/api/v3/western/compatibility/composite" \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
        "person1": {
            "year": 1990,
            "month": 5,
            "day": 20,
            "hour": 14,
            "minute": 30,
            "second": 0,
            "latitude": 28.6139,
            "longitude": 77.209,
            "timezone": "Asia/Kolkata"
        },
        "person2": {
            "year": 1992,
            "month": 8,
            "day": 15,
            "hour": 10,
            "minute": 0,
            "second": 0,
            "latitude": 19.076,
            "longitude": 72.8777,
            "timezone": "Asia/Kolkata"
        },
        "house_system": "placidus",
        "node_type": "true"
    }'

const response = await fetch(
  'https://starsapi.com/api/v3/western/compatibility/composite',
  {
    method: 'POST',
    headers: {
      'X-Api-Key': 'YOUR_API_KEY',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      person1: 'Array',
      person2: 'Array',
      house_system: 'placidus',
      node_type: 'true'
    })
  }
);
const result = await response.json();

if (result.success) {
  console.log(result.data);
}

import requests
import os

response = requests.post(
    'https://starsapi.com/api/v3/western/compatibility/composite',
    headers={'X-Api-Key': os.environ['STARSAPI_KEY']},
    json={
        'person1': 'Array',
        'person2': 'Array',
        'house_system': 'placidus',
        'node_type': 'true'
    }
)
result = response.json()

if result['success']:
    print(result['data'])

<?php
$payload = [
    'person1' => 'Array',
    'person2' => 'Array',
    'house_system' => 'placidus',
    'node_type' => 'true',
];

$ch = curl_init('https://starsapi.com/api/v3/western/compatibility/composite');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($payload));
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'X-Api-Key: ' . getenv('STARSAPI_KEY'),
    'Content-Type: application/json'
]);

$response = curl_exec($ch);
$data = json_decode($response, true);

if ($data['success']) {
    print_r($data['data']);
}

import 'package:http/http.dart' as http;
import 'dart:convert';

Future<Map<String, dynamic>> getAscendant() async {
  final response = await http.post(
    Uri.parse('https://starsapi.com/api/v3/western/compatibility/composite'),
    headers: {
      'X-Api-Key': 'YOUR_API_KEY',
      'Content-Type': 'application/json',
    },
    body: jsonEncode({
      'person1': 'Array',
      'person2': 'Array',
      'house_system': 'placidus',
      'node_type': 'true',
    }),
  );
  return jsonDecode(response.body);
}

import Foundation

func getAscendant() async throws -> [String: Any] {
    var request = URLRequest(url: URL(string:
        "https://starsapi.com/api/v3/western/compatibility/composite"
    )!)
    request.httpMethod = "POST"
    request.setValue("YOUR_API_KEY", forHTTPHeaderField: "X-Api-Key")
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    request.httpBody = """
        {
            "person1": {
                "year": 1990,
                "month": 5,
                "day": 20,
                "hour": 14,
                "minute": 30,
                "second": 0,
                "latitude": 28.6139,
                "longitude": 77.209,
                "timezone": "Asia/Kolkata"
            },
            "person2": {
                "year": 1992,
                "month": 8,
                "day": 15,
                "hour": 10,
                "minute": 0,
                "second": 0,
                "latitude": 19.076,
                "longitude": 72.8777,
                "timezone": "Asia/Kolkata"
            },
            "house_system": "placidus",
            "node_type": "true"
        }
        """.data(using: .utf8)

    let (data, _) = try await URLSession.shared.data(for: request)
    return try JSONSerialization.jsonObject(with: data) as! [String: Any]
}

import okhttp3.*
import org.json.JSONObject

val client = OkHttpClient()
val JSON = "application/json; charset=utf-8".toMediaType()

fun getAscendant(callback: (JSONObject) -> Unit) {
    val payload = """
    {
        "person1": {
            "year": 1990,
            "month": 5,
            "day": 20,
            "hour": 14,
            "minute": 30,
            "second": 0,
            "latitude": 28.6139,
            "longitude": 77.209,
            "timezone": "Asia/Kolkata"
        },
        "person2": {
            "year": 1992,
            "month": 8,
            "day": 15,
            "hour": 10,
            "minute": 0,
            "second": 0,
            "latitude": 19.076,
            "longitude": 72.8777,
            "timezone": "Asia/Kolkata"
        },
        "house_system": "placidus",
        "node_type": "true"
    }
    """.trimIndent()

    val request = Request.Builder()
        .url("https://starsapi.com/api/v3/western/compatibility/composite")
        .addHeader("X-Api-Key", "YOUR_API_KEY")
        .post(payload.toRequestBody(JSON))
        .build()

    client.newCall(request).enqueue(object : Callback {
        override fun onResponse(call: Call, response: Response) {
            callback(JSONObject(response.body!!.string()))
        }
        override fun onFailure(call: Call, e: java.io.IOException) {
            e.printStackTrace()
        }
    })
}

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "net/http"
    "os"
)

func main() {
    payload, _ := json.Marshal(map[string]interface{}{
        "person1": "Array",
        "person2": "Array",
        "house_system": "placidus",
        "node_type": "true",
    })

    req, _ := http.NewRequest("POST",
        "https://starsapi.com/api/v3/western/compatibility/composite",
        bytes.NewBuffer(payload))
    req.Header.Set("X-Api-Key", os.Getenv("STARSAPI_KEY"))
    req.Header.Set("Content-Type", "application/json")

    resp, _ := http.DefaultClient.Do(req)
    defer resp.Body.Close()

    var result map[string]interface{}
    json.NewDecoder(resp.Body).Decode(&result)
    fmt.Println(result["data"])
}

require 'net/http'
require 'json'

uri = URI('https://starsapi.com/api/v3/western/compatibility/composite')
payload = {
  'person1' => 'Array',
  'person2' => 'Array',
  'house_system' => 'placidus',
  'node_type' => 'true'
}

req = Net::HTTP::Post.new(uri)
req['X-Api-Key'] = ENV['STARSAPI_KEY']
req['Content-Type'] = 'application/json'
req.body = payload.to_json

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
res = http.request(req)

data = JSON.parse(res.body)
puts data['data'] if data['success']

200 RESPONSE

{
  "status": 200,
  "success": true,
  "data": {
    "ascendant": { "longitude": 141.2, "sign": "Leo", "degree_in_sign_dms": "21°12'00\"" },
    "midheaven": { "longitude": 51.4, "sign": "Taurus", "degree_in_sign_dms": "21°24'00\"" },
    "planets": {
      "Sun": { "longitude": 100.93, "sign": "Cancer", "degree_in_sign_dms": "10°55'48\"" },
      "Moon": { "longitude": 67.89, "sign": "Gemini", "degree_in_sign_dms": "7°53'24\"" }
    },
    "house_cusps": { "1": { "longitude": 141.2 }, "...": "..." },
    "house_system": "Placidus"
  },
  "meta": { "endpoint": "/api/v3/western/compatibility/composite", "version": "3.0" }
}