# 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.
(Private preview)
Account farming prevention is in private preview. To request access, email [radar-account-farming-prevention-interest-form@stripe.com](mailto:radar-account-farming-prevention-interest-form@stripe.com).

## 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. It doesn’t establish that a payment is fraudulent or that the customer is malicious. 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.

You can use these additional attributes to investigate related activity:

- **Account farming risk factor** (`account_farming_risk_factor`): The 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.
- **Account farming cluster ID** (`account_farming_cluster_id`): A synthetic identifier associated with the primary signal. Use it to filter for related payments. It isn’t a customer ID or a permanent identifier for an account farm.

These attributes reflect 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)