Mobile app analytics provider Localytics has raised $5.5 million in Series B funding. The round was led by Polaris Venture Partners with participation from existing investors New York Angels, Launchad Venture Group, and Hub Angels Investment Group also participated.  Localytics has now raised a total of $8.75 million to date.

Launched in 2009, the Cambridge, Mass.-based analytics company helps app developers track how their apps are used, providing real-time insights that can be used to increase engagement and spending. Localytics says its analytics platform is used by more than 10,000 apps, with more than 350 million devices in its network.

Localytics plans to use the funding to launch its new app marketing platform that allows publishers to send in-app messages to customers, encouraging them to take a certain action or make a purchase. The funds will also go toward improving its existing app analytics software platform.