Hey GeoNet-Community,
is there a tool/widget/script for AGOL or map.apps (both) to upload shapefiles or kml to an existing WebApp? I've already searched Conterra Developer Network and ESRI Marketplace and stuff; maybe you can help. 
Context is: We just developed from exporting static jpg-maps out of ArcGIS for Desktop for our clients to give them dynamic input in a WebGIS. In the communication process it's important to take the next step. Some clients and partners do have geodata - shapefiles, kml, stuff like that. If we build an App for them in which they can upload this stuff into the feature service - like it's possible with the existing editing tool, we could go this step.
Does a tool/widget like this exist? 
Does anyone in this community develop s.th like this/has developed? 
Or does anyone in this community feel like "Wow! That's easy/interesting/challenging. I wanna develop this and maybe get some reward for this" 
We are searching for a simple solution; so no FME-Maserati needed.
I'm looking forward to hearing from you guys and I am thankful for all solutions, food for thoughts, snippets of coding etc.
Greetz!