# Account farming prevention

Detect coordinated account farming and block associated card payments.

Account farming occurs when someone creates or operates multiple accounts in a coordinated way to violate your policies, such as repeatedly claiming benefits intended for new customers. Radar evaluates account farming risk when a card payment is made, using signals that connect activity across accounts.

You must be on the Radar Pro plan to access this preview feature.

### Request access to the preview for account farming prevention.

Enter your email to request access.

```bash
curl https://docs.stripe.com/preview/register \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Referer: https://docs.stripe.com/radar/account-farming" \
  -d '{"email": "EMAIL", "preview": "account_farming_prevention_preview"}'
```

## How the account farming risk level works 

Radar assigns an account farming risk level (`account_farming_risk_level`) based on signals such as reuse of payment methods, browser fingerprints, and device fingerprints across customers. Possible values are `normal`, `elevated`, and `highest`.

An elevated or highest risk level indicates patterns associated with coordinated abusive account activity. Use the risk level with your policies on account creation and reuse, and consider legitimate reasons for customers to share a payment method or device.

The account farming risk factor (`account_farming_risk_factor`) indicates the type of primary signal associated with the payment. Possible values are `payment_method`, `browser_fingerprint`, and `device_fingerprint`. When several factors apply, Radar returns one primary factor.

The risk factor reflects the information available when Radar evaluates the payment. A shared signal can appear on payments with a `normal` risk level, and related payments might have different risk levels.

## Block payments using the account farming risk level 

Use account farming attributes in [custom Radar rules](https://docs.stripe.com/radar/rules.md) to apply your policies. For example, you can write a block rule for payments with the highest account farming risk level:

```text
:account_farming_risk_level: = 'highest'
```

[Test your rule](https://docs.stripe.com/radar/testing.md) against past payments before enabling it to understand which payments it would affect.

## See also 

- [Custom Radar rules](https://docs.stripe.com/radar/rules.md)
- [Test rules](https://docs.stripe.com/radar/testing.md)