| Name | Type | Description | Notes |
|---|---|---|---|
| type | string | Attachment type (image, video, file, sticker, audio) | |
| url | string | Where to fetch the attachment. The contract differs by platform. - WhatsApp: points at `GET /v1/whatsapp/media/{mediaId}`, an authenticated Zernio endpoint. You MUST send `Authorization: Bearer <your API key>`; fetching it without that header returns `401`. Download and store the bytes when this webhook arrives: Meta drops inbound media after a limited retention window, after which the endpoint answers `400` permanently and the media is unrecoverable. - Instagram / Facebook / Telegram: a direct platform CDN link that needs no authentication and expires on the platform's own schedule. | |
| payload | object | Additional attachment metadata | [optional] |