{
  "ok": true,
  "source": "magicblock-private-payments",
  "challenge": {
    "challenge": "MOCK: Login to Query Filtering Service\nTimestamp: 2026-05-21T10:56:45.392Z\nUser: B3STL1akxLGLvPpKd6Grz19jjVySkWrGgHFwGNK8yEZ"
  },
  "next": {
    "login": "POST https://payments.magicblock.app/v1/spl/login with the wallet-signed challenge",
    "privateBalance": "GET /api/v1/magicblock/balances/{wallet}?mint={mint} with Authorization: Bearer <token>"
  }
}