Fund a wallet

A fresh wallet holds nothing: no stablecoin to move and no ETH to pay gas with. On the sandbox the fastest fix is the built-in faucet; on production (and anywhere else) wallets simply receive funds like any on-chain address.

Option 1: The faucet (sandbox only)

The faucet exists only on the Sandbox environment (Sepolia). On Production (Mainnet) it would move real funds, so POST /fund does not exist there and returns 404; fund production wallets with a real deposit (Option 2).

One call sends test stablecoin and tops up ETH for gas:

curl -s "$BASE/fund" \
  -H "Authorization: Bearer $KEY" \
  -H "content-type: application/json" \
  -d "{\"walletId\":\"$WALLET\"}"

{
  "ok": true,
  "data": {
    "transaction": {
      "id": "cktxn0001…",
      "type": "FUND",
      "status": "QUEUED",
      "amount": "1000.00",
      "token": "AROUSD",
      "txHash": null,
      "settlementTxHash": null,
      "explorerUrl": null,
      "error": null,
      "errorCode": null,
      "payout": null,
      "walletId": "ckwlt0001…",
      "createdAt": "2026-08-13T09:35:00.000Z",
      "updatedAt": "2026-08-13T09:35:00.000Z"
    }
  }
}

The 201 means the request was accepted and queued; a background worker sends the funds a few seconds later. Poll GET /transactions/{id} until the status is CONFIRMED (or FAILED) before spending the funds; see Track transactions. Details worth knowing:

amount is optional. Omit it for the deployment’s default faucet amount, or pass a decimal string like "250" to request a specific amount.
Two legs, one call. When the wallet is short of ETH, the worker first sends a gas top-up (its hash lands in metadata.gasTxHash, with metadata.gasToppedUp: true), then the stablecoin transfer, whose hash is the transaction’s txHash. settlementTxHash is not used for faucet transactions.
Rolling 24-hour cap. Faucet volume is capped per account over a rolling day. Exceeding it returns 400 faucet_cap_exceeded; the cap resets as old requests age out. Queued and pending faucet requests count toward it.
Works for external wallets too: the faucet is a plain on-chain send, so watch-only addresses can receive it.

If the transaction ends up FAILED with errorCode: "faucet_failed", the sandbox operator wallet is out of stablecoin or ETH; that’s an operational issue on the platform side, not something your integration can fix, and no funds moved. See Troubleshooting.

Option 2: Receive from anyone

Every wallet is a real on-chain address on the environment’s chain (Mainnet in production, Sepolia on the sandbox). Share it and receive stablecoin, cAROUSD, or ETH from any counterparty:

Dashboard: the Receive screen shows the address, a QR code, a copy button, and a downloadable address card.
API: fetch the address from GET /wallets/{id}, or produce a shareable .nota address card with GET /wallets/{id}/nota.

Fiat on-ramps (bank transfer, card, Ramp, MoonPay, Transak) appear in the dashboard as coming soon; on the sandbox, the faucet plays their role in the meantime.

Verify the result

curl -s "$BASE/balances?walletId=$WALLET" -H "Authorization: Bearer $KEY"

You should see normal.amount increased and a healthy eth.amount for gas. From here, mint cAROUSD to step onto the confidential rail.

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Option 1: The faucet (sandbox only)

Option 2: Receive from anyone

Verify the result

​Option 1: The faucet (sandbox only)

​Option 2: Receive from anyone

​Verify the result

Option 1: The faucet (sandbox only)

Option 2: Receive from anyone

Verify the result