---
title: "Send USDC in sandbox"
description: "Send test USDC from one sandbox wallet to another on the same network, and know which crypto sends sandbox cannot settle today."
---
Use this recipe to send test USDC from one sandbox wallet to another on the same network, and to find out which crypto sends sandbox cannot settle today.

**Who it is for.** A crypto payroll tool that pays contractors in USDC and wants to test sends between its customers' wallets.

**Status.** Available for a same-network send. Not yet available in sandbox for a cross-network send, or for a failed send on purpose.

## Money example

1. Your customer's sandbox Polygon wallet holds 200 test USDC.
2. You send 75.00 USDC to another sandbox Polygon wallet.
3. The send completes in about 3 seconds. The source wallet then shows 125, and the destination wallet shows 75.

## Before you start

- A sandbox wallet that holds test USDC. Read its balance with `GET /v1/wallets/{wallet_id}`. On EVM networks this balance is the **sandbox test dollar**. USDC from a public faucet does not show in it. Putting test dollars on a standalone EVM wallet through the API is Not yet available. Ask support if you need a funded sandbox wallet.
- A destination address on the **same** network.

## Find out what is required

The network, asset and memo rules of the destination network are the same as in live. See [Send stablecoins to an outside wallet](/recipes/remittance-and-crypto/send-stablecoins-to-an-outside-wallet).

## Steps

### 1. Send

Send a normal `POST /v1/transfer` with the crypto destination, exactly as in [Send stablecoins to an outside wallet](/recipes/remittance-and-crypto/send-stablecoins-to-an-outside-wallet), with your sandbox key. Do **not** add `_simulate_web3`.

### 2. Follow it

<CodeGroup>
```bash title="cURL"
curl --request GET \
     --url https://api.gravv.xyz/v1/transactions/1a2a73ed-562b-4f79-8374-59eef50bea63 \
     --header 'Api-Key: <API_KEY>'
```
```javascript title="Node"
const response = await fetch("https://api.gravv.xyz/v1/transactions/1a2a73ed-562b-4f79-8374-59eef50bea63", {
  method: "GET",
  headers: {
    "Api-Key": process.env.GRAVV_API_KEY,
  },
});
console.log(response.status, await response.json());
```
```python title="Python"
import os

import requests

response = requests.get(
    "https://api.gravv.xyz/v1/transactions/1a2a73ed-562b-4f79-8374-59eef50bea63",
    headers={
        "Api-Key": os.environ["GRAVV_API_KEY"],
    },
)
print(response.status_code, response.json())
```
</CodeGroup>

A same-network send settles in seconds. You receive `transfer.status.pending` events that carry a `tx_hash`, then `transfer.status.completed`. For a USDC wallet source, the transfer response shows `amount_currency` `USD`.

### 3. Read the balances

Call `GET /v1/wallets/{wallet_id}` for both wallets. A wallet can show `"stale": true` for a few minutes after a send. If it does, read it again later.

## What can go wrong

| Response | Why | Fix |
| :-- | :-- | :-- |
| The send never completes | You added `"_simulate_web3": "success"` | Remove it and send a normal transfer |
| `pending` with no event at all, and the wallet is not debited | You added `"_simulate_web3": "failed"` | Remove it |
| For a cross-network send, Gravv sends `transfer.status.failed` while the row stays `pending`, or the send stays `pending` | Cross-network sends do not settle in sandbox today | Test same-network sends only |
| 400 `insufficient balance` from a Stellar or Solana wallet | The wallet holds no test dollars | Send from a funded EVM wallet |
| 400 `invalid transfer input` | You sent `_simulate_web3` with a live key | Remove it |
| Faucet USDC does not show on an EVM sandbox wallet | EVM sandbox wallets show the sandbox test dollar | See [Fund wallets during testing](/platform/wallets/fund-wallets-during-testing) |
| `balance_before` and `balance_after` repeat on the rows | A known sandbox difference | Read the wallet balance instead |

## Webhooks you will receive

You receive the same webhooks as in live, `transfer.status.pending` and then `transfer.status.completed`.

## Testing in sandbox

This page is the sandbox guide for crypto sends. You cannot produce a failed crypto send, so test that screen with a recorded `transfer.status.failed` payload.

## Reference

- [Initiate a transfer](/api-reference/transfer/post-v1-transfer)
- [Get a single wallet](/api-reference/wallets/get-v1-wallets-wallet-id)