Attach your user id to a member

{
  "id": "mem_01JMZX1Z7D",
  "created_at": "2026-05-01T12:00:00Z",
  "identities": [
    {
      "platform": "discord",
      "platform_uid": "218421075025461248",
      "username": "ari"
    }
  ],
  "external_subjects": [
    {
      "namespace": "production",
      "external_user_id": "usr_7f921"
    }
  ]
}

{
  "type": "https://docs.arcalotl.com/api/errors#invalid_request",
  "title": "Bad Request",
  "status": 400,
  "detail": "The 'cursor' parameter is not a valid cursor from a previous response.",
  "code": "invalid_request"
}

{
  "type": "https://docs.arcalotl.com/api/errors#unauthorized",
  "title": "Unauthorized",
  "status": 401,
  "detail": "A valid API key is required. Provide it as 'Authorization: Bearer arclt_live_...'.",
  "code": "unauthorized"
}

{
  "type": "https://docs.arcalotl.com/api/errors#missing_scope",
  "title": "Forbidden",
  "status": 403,
  "detail": "This API key is missing the required scope: subscriptions:read.",
  "code": "missing_scope"
}

{
  "type": "https://docs.arcalotl.com/api/errors#not_found",
  "title": "Not Found",
  "status": 404,
  "detail": "The requested resource was not found.",
  "code": "not_found"
}

{
  "type": "https://docs.arcalotl.com/api/errors#request_in_flight",
  "title": "Conflict",
  "status": 409,
  "detail": "Another request with this Idempotency-Key is still in flight.",
  "code": "request_in_flight"
}

{
  "type": "https://docs.arcalotl.com/api/errors#invalid_request",
  "title": "Unprocessable Entity",
  "status": 422,
  "detail": "One or more request values are invalid.",
  "code": "invalid_request"
}

{
  "type": "https://docs.arcalotl.com/api/errors#rate_limited",
  "title": "Too Many Requests",
  "status": 429,
  "detail": "Rate limit exceeded. Retry after the interval in the Retry-After header.",
  "code": "rate_limited"
}