Lagu GBKP - Kitab Ende-Enden is a free Android multimedia app developed by J Silangit. This app is designed to help the congregation of GBKP learn songs from the book ende-endeen, penambahen ende-Enden, supplements ende-Enden, and studying the sheet music choir. It also provides users with a mechanism for sharing arrangements. The app features an editing tool that allows users to format errors or even add new poems that do not exist. In addition, there is a video guide for editing poems and a guide to add/edit notation and lyrics. The app also has a score mode feature that displays selected songs in sheet music form complete with lyrics and song notation. The notation used is designed in the form of "Not Angka" so it's easy to read and develop. The notation is divided into Soprano Alto Tenor choir (SATB) to represent the sound of 1, 2, 3, and 4. However, the first version of the app is not yet complete and there are still a lot of typos and formatting issues, especially with the notation database. The app is expected to improve with user participation in correcting and editing existing lyrics and adding notation, especially for soprano and SATB harmony.