> ## Documentation Index
> Fetch the complete documentation index at: https://apidocs.bridge.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Transfer features

## **Flexible Amounts**

<Tip>
  **We strongly recommend** using a flexible amounts to avoid payment validation failures.
</Tip>

To create a Transfer that will match any funds sent using the source deposit instructions regardless of amount, use the `flexible_amount` feature.

Because the amount is not known ahead of time, Transfers with the `flexible_amount` feature only support a percentage based `developer_fee_percent`. Flexible amount Transfers do not support setting a fixed `developer_fee`.

**Note:** Static templates have this feature enabled automatically if no amount is provided when they are created.

```bash Request expandable theme={null}
curl --location --request POST 'https://api.bridge.xyz/v0/transfers' \
--header 'Api-Key: <API Key>' \
--header 'Idempotency-Key: <Unique Idempotency Key>' \
--data-raw '{
  "on_behalf_of": "cust_alice",
  "source": {
    "payment_rail": "wire",
    "currency": "usd",
  },
  "destination": {
    "payment_rail": "ethereum",
    "currency": "usdc",
    "to_address": "0xdeadbeef",
  },
  "developer_fee_percent": "1.0", // A 1% developer fee
  "features": {
    "flexible_amount": true,
  }
}'
```

```json Response expandable theme={null}
{
  "id": "flexible_transfer_789",
  "state": "awaiting_funds",
  "on_behalf_of": "cust_alice",
  "source": {
    "payment_rail": "wire",
    "currency": "usd"
  },
  "destination": {
    "payment_rail": "polygon",
    "currency": "usdc",
    "to_address": "0xdeadbeef"
  },
  "source_deposit_instructions": {
    // ...Bridge banking details
    "currency": "usd",
    "deposit_message": "BVI7depositmessage",
  },
 "features": {
    "flexible_amount": true
  },
  "created_at": "2023-05-05T19:39:14.316Z",
  "updated_at": "2023-05-05T19:39:15.231Z"
}
```

After Bridge receives funds and matches them to the Transfer, the amount will be included in API responses.

```json Response theme={null}
{
  "id": "flexible_transfer_789",
  "amount": "1337.0",
  ...
}
```

## **Allow Any From Address**

<Tip>
  **We strongly recommend** using this feature especially for crypto deposits. If your customer sends funds from an exchange, they won't be able to control the sending address.
</Tip>

```bash Request theme={null}
...
"features": {
  "allow_any_from_address": true,
}
...
```

* By default, Bridge requires the sending address of the wallet sending the funds to be specified upon creating a Transfer.
* For some use cases like consumer sending funds from an exchange, this is difficult or impossible to know ahead of time.
* To support these use cases, Bridge has the `allow_any_from_address` feature.
* If this feature is enabled, no `from_address` needs to be specified at Transfer creation time and any funds sent to the source deposit instructions will be matched regardless of the `from_address`.