> ## Documentation Index
> Fetch the complete documentation index at: https://docs-en.keysecure.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Transfer(Withdrawal) Callback

**Co-Signer** calls back to the client system to confirm whether the withdrawal is normal before signing.

`Content-Type application/json;charset=UTF-8`

#### Callback Request Parameters

| Param | Type | Requried | Description |
| :- | :- | :- | :- |
| type | String | Yes | Callback type,`sign_prepare`prepare to Sign， `sign_start`start signing，`sign_success`successfully signed. |
| transfer\_id | Integer | Yes | transfer id, example: 12345 |
| request\_id | String | Yes | The unique identifier for initiating transfer |
| pending\_round | Bool | Yes | Speed Up status, `false` means in transferring transaction , `true` means speeding up the transaction |
| from | String | Yes | from account address |
| to | String | Yes | to account address |
| memo | String | No | to account address memo，example：123321 |
| amount | Decimal | Yes | Transaction amount |
| symbol | String | Yes | The unique identifier of the coin, example: USDTERC20 |
| txid | String | No | Transaction hash. Returned when the signature is successful. |
| outputs | String | No | UTXO withdrawal details to multiple addresses, in JSON format |

```curl cURL theme={null}
curl -X POST \
--url 'https://custom-url/example-callback' \
--data '{
  "amount": "0.3",
  "from": "n2jRrmPLqmaDfcwsSEKfbx9bFs7FgZM2HY",
  "memo": "",
  "pending_round": false,
  "request_id": "c70d1eebb7c687ec8d56bead73f104",
  "symbol": "BTC",
  "to": "32BfKjhByDSxx3BM5vUkQ3NQq9csZR6nt8",
  "txid": "",
  "type": "sign_start",
  "withdraw_id": "",
  "outputs": "[{\"address_to\":\"32BfKjhByDSxx3BM5vUkQ3NQq9csZR6nt8 \",\"amount\":\"0.1\"},{\"address_to\":\"32BfKjhByDSxx3BM5vUkQ3NQq9csZR6nt7 \",\"amount\":\"0.1\"},{\"address_to\":\"0x5EDc9177997Bf6B4db559A5C184051858B3B3709\",\"amount\":\"0.1\"}]"
}'
```

#### Callback Response Parameters

Return string：

* `SUCCESS` means SUCCESS: Co-Signer signs the transaction.
* `FAILURE` means FAILURE: Co-Signer will ignore the transaction and not sign.


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