# Velocity Checking on User ID

_March 21, 2023_

> **⚠️ Warning**
>
> This release note is more than two years old and may no longer reflect
> current behavior. View the
> [latest release notes](/minfraud/release-notes/).

We have enabled velocity tracking on the `account/user_id` input for all
minFraud customers.

If you send a user ID associated with your transactions, minFraud will now
factor the velocity of the user's transactions into the risk score.

The `account/user_id` input allows you to pass a unique identifier for each of
your users so that the minFraud service can group transactions by user in order
to identify fraud signals attached to specific users.

[Learn more about the `account/user_id` input on our Developer Portal.](/minfraud/api-documentation/requests#schema--request--account__user_id)

[Learn more about velocity tracking on our Knowledge Base.](https://support.maxmind.com/knowledge-base/articles/minfraud-services-velocity-checks)