---
title: "Biorhythm Compatibility"
method: POST
path: "/wellness/biorhythm/compatibility"
tags: ["Wellness"]
---

# Biorhythm Compatibility

`POST /wellness/biorhythm/compatibility`

## Request

- Base URL: `https://api.astroway.info/v1`
- URL: `https://api.astroway.info/v1/wellness/biorhythm/compatibility`
- Auth: API key in header `X-Api-Key`
- TypeScript: <https://skmtc.dev/astroway/apis/astroway-calculation-api/docs/wellness/biorhythm/compatibility/post.ts> (a function with typed inputs; its response is checked against the schema)

How closely two people's 23, 28 and 33-day cycles run together: per cycle the phase offset in days and 50 x (1 + cos(2 pi x offset / period)), and their mean. The offset is set at birth, so the figure never changes. A historical model with no evidential support, returned with that disclaimer.

## Query parameters

- `fields` string
- `precision` integer

## Headers

- `Idempotency-Key` string

## Request body

- BiorhythmCompatibility
  - `birthDateA` string, required
  - `birthDateB` string, required

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `birthDateA` string, nullable
    - `birthDateB` string, nullable
    - `daysApart` number, nullable
    - `cycles` object[], nullable
      - `name` string, nullable
      - `periodDays` number, nullable
      - `phaseOffsetDays` number, nullable
      - `syncPercent` number, nullable
    - `overallPercent` number, nullable
    - `formula` string, nullable
    - `disclaimer` string, nullable

## Other responses

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

## Changes

- **2026-11-07** `bf266b2e6703`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/astroway/apis/astroway-calculation-api/changes/wellness/biorhythm/compatibility/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.dev/astroway/apis/astroway-calculation-api/revisions/bf266b2e6703?raw)