Register a push device

POST/push/devices

Store an FCM registration token so the user can receive push notifications for new chat messages. Registration is idempotent on token, so re-sending the same token does not create duplicates. If the token already belongs to another user (device hand-off or account switch), ownership moves to the authenticated user. A previously disabled token is re-enabled.

Auth	Login required

Request body

tokenstringrequired

FCM registration token.

platformstringrequired

One of IOS / ANDROID / WEB.

localestring

Locale for notification text (e.g. ja / en). Falls back to the user's language settings when omitted.

Notes

Devices are scoped to the app (OAuth client) that registered them. Devices registered by other apps are neither listed nor deletable.

Revoking the app's authorization also deletes the devices it registered, so push notifications stop.

When FCM reports a token as unregistered, the device is automatically excluded from future deliveries.

Response

Field	Type	Description
`id`	string	Device ID, used when unregistering.
`tokenMasked`	string	Only the tail of the token. The full token is never returned.
`platform`	string	IOS / ANDROID / WEB.
`clientId`	string \| null	OAuth client ID that registered the device.
`locale`	string \| null	Locale for notification text.
`lastUsedAt`	string \| null	Last successful delivery (ISO 8601).
`createdAt`	string	Created at (ISO 8601).
`updatedAt`	string	Updated at (ISO 8601).

Request
curl https://api.4s.link/push/devices \
  -X POST \
  -H "Authorization: Bearer 4s_at_..." \
  -H "Content-Type: application/json" \
  -d '{
  "token": "fcm-registration-token-...",
  "platform": "IOS",
  "locale": "ja"
}'

Example response
{
  "id": "b7c1a2d3-...",
  "tokenMasked": "...9fA2xQ",
  "platform": "IOS",
  "clientId": "a1b2c3d4-...",
  "locale": "ja",
  "lastUsedAt": null,
  "createdAt": "2026-08-18T09:00:00.000Z",
  "updatedAt": "2026-08-18T09:00:00.000Z"
}