By topic / Synastry API
Synastry API: how two charts meet
Compare two birth charts: every aspect between them, a score, a composite chart, and readings on love, friendship and lasting bonds. There is a simple Sun and rising match too, for people with no birth time.
What people build with it
- Compatibility in a dating app
- Couple reports
- Friendship features
The endpoints
- Synastry Chart
Both people's positions, the aspects between their charts, and a compatibility block with score, Sun and Moon compatibility and a verdict.
POST /v1/western/synastry-chart
1 credit
- Synastry Compatibility Score
A synastry compatibility score with Sun and Moon compatibility, aspect counts and a verdict.
POST /v1/western/synastry-compatibility
1 credit
- Synastry Aspects
Inter-chart aspects between two people, split into harmonious and challenging, with orb and meaning.
POST /v1/western/synastry-aspects
1 credit
- Synastry: Everything
Compatibility, all five domain readings ranked (career, finance, intimacy, spirituality, emotion) and the sun-sign match, in one call.
POST /v1/western/synastry-full
10 credits
- Composite Relationship Chart
A relationship chart from the midpoint of each body between two births, with houses derived from the composite midheaven at the births' midpoint latitude.
POST /v1/western/western-composite-chart
1 credit
- Love Contacts
Contacts between two charts that bear on love: Venus, Mars, the Sun and the Moon.
POST /v1/western/western-love-contacts
1 credit
- Friendship Report
Contacts between two charts that bear on friendship: Sun, Moon, Mercury and Jupiter.
POST /v1/western/western-friendship-report
1 credit
- Sun and Rising Compatibility
A compatibility percentage and verdict from two people's Sun and rising signs, scoring each pairing, with a summary. It needs no birth time.
POST /v1/western/western-sun-rising-match
1 credit
- Star Sign Compatibility Report
Both personalities and every love, friendship and lasting-bond contact between two charts, as one report.
POST /v1/reports/report-star-sign-compatibility
10 credits
Common questions
- Does it need both birth times?
- A full synastry does. western-sun-sign-match and western-sun-rising-match work from signs alone.

