---
title: "Midpoints"
method: POST
path: "/midpoints"
tags: ["Aspects & Points"]
---

# Midpoints

`POST /midpoints`

Calculate all planetary midpoints and their zodiac positions. Optionally include midpoint aspects to natal points.

## Request body

- ChartInput — Birth data for a single natal chart. Required: date (YYYY-MM-DD), time (HH:mm:ss), latitude and longitude in decimal degrees. The short forms lat, lon, lng and tz are rejected with 400 INVALID_FIELD; pass the full names. timezoneOffset is hours from UTC and defaults to 0, meaning UTC. city is a display label only: nothing here geocodes it, so it never stands in for coordinates.
  - `date` string, required
  - `time` string, required
  - `timezoneOffset` number, nullable
  - `latitude` number, required
  - `longitude` number, required
  - `houseSystem` string
  - `name` string
  - `city` string
  - `zodiacType` 'tropical' | 'sidereal'
  - `ayanamsaId` number, nullable
  - `cosmogram` boolean

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `midpoints` object[], nullable
      - `planet1` string, nullable
      - `planet2` string, nullable
      - `longitude` number, nullable
      - `sign` string, nullable
      - `aspects` unknown[], nullable
        - unknown

## Other responses

- `400` — Validation error
- `401` — Missing or invalid API key

## Changes

- **2026-08-11** `b0533bcc12c0` — 4 breaking, 4 warning, 2 info
  - the request property `latitude` became not nullable
  - the request property `longitude` became not nullable
  - the request property `latitude` became required
  - the request property `longitude` became required
  - …6 more

[Change history](https://skmtc.dev/astroway/apis/astroway-calculation-api/changes/midpoints/post.md)

---

[API](https://skmtc.dev/astroway/apis/astroway-calculation-api.md) · [All operations](https://skmtc.dev/astroway/apis/astroway-calculation-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/astroway/astroway-calculation-api/revisions/821c8bafa295/schema)