Transits API

Request

A real request for the demonstration chart, for one month:

curl -X POST https://api.natalchart.ai/v1/transits \
  -H "Authorization: Bearer $NATALCHART_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"birth":{"date":"1991-09-06","time":"18:30","latitude":50.4501,"longitude":30.5234},"from":"2026-09-18","to":"2026-10-18"}'

Response

Part of the answer to that request: the main fields, with every list cut to its first three items.

{
  "window": {
    "from": "2026-09-18",
    "to": "2026-10-18"
  },
  "events": [
    {
      "kind": "aspect",
      "at": "2026-09-19T10:10:33.151Z",
      "date": "2026-09-19",
      "position": "14°06′ Libra",
      "house": 8,
      "body": "Mercury",
      "target": "Neptune",
      "aspect": "Square",
      "exactness": 0,
      "targetPosition": "14°06′ Capricorn",
      "targetHouse": 11,
      "significance": "low"
    },
    {
      "kind": "aspect",
      "at": "2026-09-22T09:53:49.800Z",
      "date": "2026-09-22",
      "position": "18°00′ Leo",
      "house": 7,
      "body": "Jupiter",
      "target": "Pluto",
      "aspect": "Square",
      "exactness": 0,
      "targetPosition": "18°00′ Scorpio",
      "targetHouse": 8,
      "significance": "low"
    },
    {
      "kind": "aspect",
      "at": "2026-09-23T20:47:58.234Z",
      "date": "2026-09-23",
      "position": "0°51′ Libra",
      "house": 7,
      "body": "Sun",
      "target": "Saturn",
      "aspect": "Trine",
      "exactness": 0,
      "targetPosition": "0°51′ Aquarius",
      "targetHouse": 12,
      "significance": "low"
    }
  ]
}

What comes back

• window: the dates you asked for.
• events: up to 60 exact aspects from transiting bodies to natal ones, sign ingresses and stations, in date order, each with its moment in UTC, its position and the houses involved. When a window holds more, the most significant are kept.
• activeOnFirstDay: the transits already within orb on the first day, with the orbs used.
• Each event carries a significance (high, medium or low) from the bodies involved.

Limits

• API Pro only, at most 92 days and 60 events per request. On the free key the endpoint answers 403 with a link to upgrade.
• Births from 1800 to 2399. The houses of a transit need a birth time; without one they are left out.
• Each exact moment is searched with the Swiss Ephemeris and given in UTC.
• Birth data is read, used and forgotten: request bodies are never stored.

In an AI assistant

Through the MCP server at https://www.natalchart.ai/mcp, assistants call the transits tool for a period and daily_transits for a single day, and read real transits instead of guessing them.

The rest of the API

The same key opens the whole astrology API: natal charts, daily transits, synastry, transits for a period, solar returns, best days and astrocartography. Every endpoint, field and error is in the documentation, and the pricing page says what counts as a request.

Questions