Worldata is offering an enhanced subject line testing tool called SubjectLine.com.

The app allows marketers to test subject lines for potential deliverability and marketability issues that could affect campaign performance.

Designed to help marketers improve their open rates, the free service is “based on analysis of over 5 billion email messages transmitted and tracked,” states Worldata CEO Jay Schwedelson.

Over 900 rules are applied throughout the testing process, the company adds.

Worldata is a direct marketing media company that provides online and offline services.