By default, Sift collects user IPs from the JavaScript snippet. If that’s the case for your integration, it’s possible that you may see an occasional user who doesn’t have an IP address. This is usually caused by the user blocking Sift’s JavaScript. Another possible cause of this is if the JavaScript is running on a page which the user never visited.

You can choose to send the user's request IP address via any event from our Events API by including the field $ip and providing the IP address as a String value.