Online Fraud Detection API
This tool is designed to help prevent online fraud with credit card. It compares the transaction shipping / billing information with IP geolocation data for all countries. For USA and Canada, the API also confirm area code and postal/zip code information. It is very flexible, parameters weight (how it influence the final fraud score) can be set manually. Here are 2 screenshots taken from a live store : good transaction and fraudulent transaction. The API only ask "incomplete" data about the transaction to respect privacy.
If you are looking for XML-based web service solution, please visit FraudLabs.com for more information.