Google is planning to launch a new health service called Google Fit to collect and aggregate data from popular fitness trackers and health-related apps, according to multiple sources with knowledge of the company’s plans. It will launch the service at the Google I/O conference for developers, being held on June 25 and 26. Such a service would mark a direct challenge to Apple’s HealthKit framework, launched last week and rolling out with its new mobile platform iOS 8 this fall to aggregate data from wearable devices and apps. Last month Samsung also unveiled Sami, a biometric data platform that collects health information from devices and apps too. Google Fit will aggregate data through open APIs, instruction sets that allow apps to share information, and will also announce partnerships with wearable device makers at its I/O conference, Forbes understands.