POSThttps://yogataraapi.prahlad.app/api/astro/western/synastry/

Synastry

Request bodyJSON

Paste an API key above to send.

Code snippet

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}'

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.

Request 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

Full reference for this endpoint