An SNS(Social Network Service) is an online service that supports an effective way to share information over virtual communities. Recently, as SNSs such as Twitter, Facebook, and Me2day are getting bigger, the purposes of using popular SNSs are expanded to broadcastings, politics, marketings and so on. In this paper, we propose an API to integrate and manage open APIs for various SNSs, presenting a library as an implementation of the proposed API. Also, utilizing the developed library, a smartphone application is provided which supports integrated management of popular SNSs and personal schedules. Using the library, developers can reduce costs when they need to implement specific functions for managing various SNSs. With the developed application, we can read and write to/from the related SNSs on same screen, automatically reminding our schedule and sharing the schedule with friends over the SNSs.