Developer here. Thanks for checking out my app, Riker. In case anyone is
curious, the iOS app is native, written in Obj-C. The Riker web app is written
using React and Redux. The REST API is written in Clojure and the backend is
Postgres.
Although there is also a fully functional web version of Riker, the app is
preferred since it supports offline mode, provides Watch App and integrates with
Apple's Health app.
Will be happy to answer any questions.
App Store link: https://itunes.apple.com/us/app/riker/id1196920730?mt=8
Web link: https://www.rikerapp.com