Google's Safe Browsing feature has been around since 2007, and has protected millions of people from harmful threats on the internet. It's a blacklist of harmful websites, such as those distributing malware and phishing scams, that Google actively updates every day. The database is used by Chrome, Firefox, and even Safari to ensure users can be as safe as possible online.
Back at Google I/O, Google announced they would make an official API for applications to check a given website in the Safe Browsing database. Starting with Google Play Services 9.4, developers can finally use the API in their apps.
The Safe Browsing API uses the latest version of the Safe Browsing Network Protocol, meaning it's designed to be as quick (and use up as little cellular data) as possible. Apps that use this API can specify what threats they want to avoid, either malware or phishing sites. The API is part of Google Play Services, meaning it's available to applications all the way back to Android 2.3.
- Google Security Blog