If you are into creating your own apps that run on many platforms, then AppStudio for ArcGIS might be for you. ESRI has release version 1.0 and some of the highlights are:
- Easy to publish apps to the Apple App Store and Google Play Store
- Build apps for multiple platforms with one code base
- Gives developers tools to build powerful custom apps
- Share your apps with the public or within your organization
- Basic and Standard license options
For more info and to try AppStudio, see their blog post here.