---
title: "Register Retrograde-Start Webhook"
method: POST
path: "/webhooks/retrograde-start"
tags: ["Webhooks"]
---

# Register Retrograde-Start Webhook

`POST /webhooks/retrograde-start`

Fires when any of Mercury–Pluto stations retrograde.

## Request body

- Register
  - `url` string, uri, required

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `id` number, nullable
    - `event` string, nullable

## Other responses

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

---

[API](https://skmtc.net/astroway/apis/astroway-calculation-api.md) · [All operations](https://skmtc.net/astroway/apis/astroway-calculation-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/astroway/astroway-calculation-api/revisions/529d7d36d7d6/schema)