Western relationships¶

POST /v1/western/relationships returns a full deterministic Western relationship report for two stored Western charts.

Required scope: compatibility:read

This endpoint does not replace POST /v1/compatibility. The compatibility endpoint is the persisted high-level report combining Vedic Ashtakoota and basic Western synastry. This endpoint is the detailed Western factor surface for product UI and LLM grounding.

Request¶

{
  "chart_a_id": "019e32b1-0f8f-7793-a6ef-8f7dcaef7d2b",
  "chart_b_id": "019e32b1-a0af-70f2-a199-4c0e10b81c4d"
}

Field	Type	Required	Notes
`chart_a_id`	UUIDv7	yes	Must belong to the caller's tenant.
`chart_b_id`	UUIDv7	yes	Must be distinct from `chart_a_id`.

Both charts must be system="western". Otherwise the API returns 422.

Response¶

{
  "chart_a_id": "019e32b1-...",
  "chart_b_id": "019e32b1-...",
  "synastry_matrix": [
    {
      "planet_a": "venus",
      "planet_b": "mars",
      "aspect": "trine",
      "orb_degrees": 1.42,
      "strength": 0.7971,
      "is_applying": true,
      "tone": "harmonious"
    }
  ],
  "overlays": [
    {
      "source_chart": "a",
      "planet": "moon",
      "target_house": 7
    }
  ],
  "composite_chart": {
    "id": "composite:019e32b1-...:019e32b2-...",
    "system": "western",
    "house_system": "placidus",
    "planets": []
  },
  "davison_chart": {
    "id": "019e42f0-...",
    "system": "western",
    "house_system": "placidus",
    "planets": []
  },
  "key_contacts": [
    {
      "contact_type": "venus_mars",
      "planet_a": "venus",
      "planet_b": "mars",
      "aspect": "trine",
      "orb_degrees": 1.42,
      "strength": 0.7971
    }
  ],
  "score_breakdown": [
    {
      "category": "emotional",
      "score": 0.71,
      "signals": ["sun_moon", "angle_contact"]
    }
  ]
}

Components¶

Synastry matrix¶

Full cross-chart matrix for Sun-Pluto, Ascendant, and Midheaven. Each cell contains the strongest configured aspect for that pair, if any.

House overlays¶

Bidirectional overlays:

chart A planets in chart B houses;
chart B planets in chart A houses.

Composite chart¶

Midpoint composite: zodiacal midpoints for planets and house cusps.

Davison chart¶

Real chart cast for the midpoint in time and midpoint in space between the two charts.

Key contacts¶

High-signal contact families:

venus_mars
moon_saturn
sun_moon
angle_contact

Score breakdown¶

Deterministic normalized scores in [0, 1]:

emotional
sexual
long_term
communication
conflict

These are product scores derived from synastry contacts and overlays, not final prose interpretations.