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

# Anti-fraud

> Managing risk in your transaction flow

As part of [Flow](/guides/dashboard/flow) our system allows you to build rules
which use decisions and scores from anti-fraud services.

<img src="https://mintlify.s3.us-west-1.amazonaws.com/mattilda/assets/images/anti-fraud/flow-rule.png" alt="Flow rule with an anti fraud decision" />

You can use these scores and decisions for [card transactions](/guides/dashboard/flow/card-transactions)
to evaluate the risk of a transaction and take
appropriate actions to, for example, force 3-D Secure, decline a transaction, or route to
a specific payment service.

## How does it work?

For every transaction, your anti-fraud service will only be called **once**.

When a request is made for a transaction, your active anti-fraud provider will only be called
once, assuming a rule is triggered for which an anti-fraud score or decision is the condition.
This feature will prevent incurring any extra cost by calling your anti-fraud service multiple times,
or calling your service unnecessarily if the rule is not triggered.