/api/astro/western/synastry/1 creditSynastry
Every aspect between two people's charts. Synastry compares one chart against another body by body, so a contact like 'her Venus trine his Mars' is a relationship between two DIFFERENT charts and has no equivalent inside either one. That is why a natal aspect grid cannot answer it: there a body never aspects itself, while here Sun-to-Sun is one of the most-read contacts there is. Returns both charts' positions and every cross-aspect, tightest orb first. `orb_factor` scales the whole aspect table if you work to tighter or wider orbs than the conventional ones — 0.5 halves them, 2 doubles them.
https://yogataraapi.prahlad.app/api/astro/western/synastry/Authentication
Send your key in the X-API-Key header. Keys are server-side credentials — never put one in browser JavaScript or a mobile app.
X-API-Key: yt_live_a1b2c3d4_…
Content-Type: application/jsonRequest fields
| Field | Type | Required | Notes |
|---|---|---|---|
| date_time | string (date-time) | required | The moment to calculate for, ISO 8601. ALWAYS include an offset or a trailing Z - a value with no zone is read as Asia/Kolkata (UTC+05:30), not UTC, and can return the previous day's result with a 200. '2026-09-01T06:00:00Z' and '2026-09-01 06:00:00' are different instants and give different answers. |
| partner_date_time | string (date-time) | required | |
| keys | array | optional | Which calculations to return, as a list of names. See the key table for this endpoint; an unrecognised name rejects the whole request. One call costs one credit however many keys you ask for, so request everything you need at once rather than making several calls. |
| latitude | number (double) | optional | Latitude of the place, in decimal degrees. Positive is north, negative is south. Example: 26.9124 for Jaipur, 40.7128 for New York. Minutes and seconds are not accepted - convert first. |
| longitude | number (double) | optional | Longitude of the place, in decimal degrees. Positive is east, negative is west. Example: 75.7873 for Jaipur, -74.0060 for New York. Note the sign: a missing minus puts New York in China. |
| orb_factor | number (double) | optional | Scale every aspect orb. 0.5 halves them, 2 doubles them. min 0.1 · max 2 |
| partner_timezone_as_float | number (double) | optional | min -12 · max 14 |
| timezone_as_float | number (double) | optional | UTC offset of the place, in hours, as a decimal. Example: 5.5 for India (UTC+05:30), -5 for New York in winter, 5.75 for Nepal. This is NOT validated against date_time - if the two disagree you get a successful response for the wrong moment, so derive both from the same source. Use the offset in force on that date, not today's: a summer birth in a country with daylight saving needs the summer offset. min -12 · max 14 |
Example request
curl -X POST https://yogataraapi.prahlad.app/api/astro/western/synastry/ \
-H "X-API-Key: $OCCULT_API_KEY" \
-H "Content-Type: application/json" \
-d '{"date_time":"1990-05-10T19:55:00+05:30","timezone_as_float":5.5,"latitude":26.9124,"longitude":75.7873,"partner_date_time":"1988-11-23T07:15:00+05:30","partner_timezone_as_float":5.5,"orb_factor":1}'Response
{
"_truncated": true,
"_note": "Response shortened for the catalogue.",
"preview": "{\"data\": {\"zodiac\": \"tropical\", \"orb_factor\": 1.0, \"person_a\": [{\"name\": \"sun\", \"longitude\": 49.66766, \"speed\": 0.96609, \"retrograde\": false, \"sign\": \"Taurus\", \"sign_index\": 2, \"degree_in_sign\": 19.6677, \"formatted\": \"19°40' Taurus\"}, {\"name\": \"moon\", \"longitude\": 238.259725, \"speed\": 11.874218, \"retrograde\": false, \"sign\": \"Scorpio\", \"sign_index\": 8, \"degree_in_sign\": 28.2597, \"formatted\": \"28°15' Scorpio\"}, {\"name\": \"mercury\", \"longitude\": 39.452338, \"speed\": -0.452198, \"retrograde\": true, \"sign\": \"Taurus\", \"sign_index\": 2, \"degree_in_sign\": 9.4523, \"formatted\": \"9°27' Taurus\"}, {\"name\": \"venus\", \"longitude\": 7.250368, \"speed\": 1.132131, \"retrograde\": false, \"sign\": \"Aries\", \"sign_index\": 1, \"degree_in_sign\": 7.2504, \"formatted\": \"7°15' Aries\"}, {\"name\": \"mars\", \"longitude\": 344.690843, \"speed\": 0.744344, \"retrograde\": false, \"sign\": \"Pisces\", \"sign_index\": 12, \"degree_in_sign\": 14.6908, \"formatted\": \"14°41' Pisces\"}, {\"name\": \"jupiter\", \"longitude\": 98.630274, \"speed\": 0.182781, \"retrograde\": false, \"sign\": \"Cancer\", \"sign_index\": 4, \"degree_in_sign\": 8.6303, \"formatted\": \"8°37' Cancer\"}, {\"name\": \"saturn\", \"longitude\": 295.313114, \"speed\": -0.009099, \"retrograde\": true, \"sign\": \"Capricorn\", \"sign_index\": 10, \"degree_in_sign\": 25.3131, \"formatted\": \"25°18' Capricorn\"}, {\"name\": \"uranus\", \"longitude\": 279.296197, \"speed\": -0.021248, \"retrograde\": true, \"sign\": \"Capricorn\", \"sign_index\": 10, \"degree_in_sign\": 9.2962, \"formatted\": \"9°17' Capricorn\"}, {\"name\": \"neptune\", \"longitude\": 284.419553, \"speed\": -0.012489, \"retrograde\": true, \"sign\": \"Capricorn\", \"sign_index\": 10, \"degree_in_sign\": 14.4196, \"formatted\": \"14°25' Capricorn\"}, {\"name\": \"pluto\", \"longitude\": 226.304012, \"speed\": -0.028026, \"retrograde\": true, \"sign\": \"Scorpio\", \"sign_index\": 8, \"degree_in_sign\": 16.304, \"formatted\": \"16°18' Scorpio\"}, {\"name\": \"north_node\", \"longitude\": 310.874753, \"speed\": -0.221102, \"retrograde\": true, \"sign\": \"Aquarius\", \"sign_index\": 11, \"degree_in_sign\": 10.8748, \"formatted\": \"10°52' Aquarius\"}, {\"name\": \"chiron\", \"longitude\": 102.832128, \"speed\": 0.075226, \"retrograde\": false, \"sign\": \"Cancer\", \"sign_index\": 4, \"degree_in_sign\": 12.8321, \"formatted\": \"12°49' Cancer\"}], \"person_b\": [{\"name\": \"sun\", \"longitude\": 240.991341, \"speed\": 1.010456, \"retrograde\": false, \"sign\": \"Sagittarius\", \"sign_index\": 9, \"degree_in_sign\": 0.9913, \"formatted\": \"0°59' Sagittarius\"}, {\"name\": \"moon\", \"longitude\": 53.223187, \"speed\": 14.269097, \"retrograde\": false, \"sign\": \"Taurus\", \"sign_index\": 2, \"degree_in_sign\": 23.2232, \"formatted\": \"23°13' Taurus\"}, {\"name\": \"mercury\", \"longitude\": 236.280707, \"speed\": 1.58798, \"retrograde\": false, \"sign\": \"Scorpio\", \"sign_index\": 8, \"degree_in_sign\": 26.2807, \"formatted\": \"26°16' Scorpio\"}, {\"name\": \"venus\", \"longitude\": 209.393508, \"speed\": 1.232018, \"retrograde\": false, \"sign\": \"Libra\", \"sign_index\": 7, \"degree_in_sign\": 29.3935, \"formatted\": \"29°23' Libra\"}, {\"name\": \"mars\", \"longitude\": 3.919152, \"speed\": 0.292498, \"retrograde\": false, \"sign\": \"Aries\", \"sign_index\": 1, \"degree_in_sign\": 3.9192, \"formatted\": \"3°55' Aries\"}, {\"name\": \"jupiter\", \"longitude\": 61.054447, \"speed\": -0.136364, \"retrograde\": true, \"sign\": \"Gemini\", \"sign_index\": 3, \"degree_in_sign\": 1.0544, \"formatted\": \"1°03' Gemini\"}, {\"name\": \"saturn\", \"longitude\": 271.108557, \"speed\": 0.107531, \"retrograde\": false, \"sign\": \"Capricorn\", \"sign_index\": 10, \"degree_in_sign\": 1.1086, \"formatted\": \"1°06' Capricorn\"}, {\"name\": \"uranus\", \"longitude\": 269.459759, \"speed\": 0.054838, \"retrograde\": false, \"sign\": \"Sagittarius\", \"sign_index\": 9, \"degree_in_sign\": 29.4598, \"formatted\": \"29°27' Sagittarius\"}, {\"name\": \"neptune\", \"longitude\": 278.52942, \"speed\": 0.03151, \"retrograde\": false, \"sign\": \"Capricorn\", \"sign_index\": 10, \"degree_in_sign\": 8.5294, \"formatted\": \"8°31' Capricorn\"}, {\"name\": \"pluto\", \"longitude\": 223.244883, \"speed\": 0.039039, \"retrograde\": false, \"sign\": \"Scorpio\", \"sign_index\": 8, \"degree_in_sign\": 13.2449, \"formatted\": \"13°14' Scorpio\"}, {\"na"
}Captured from a real call using the exact request above. Results sit under data.
Errors
Metering errors return { "error": "…", "message": "<code>", "is_error": true }. Show error to people and branch on message. See the error reference.