We have this soon to be published package for DynamicGrids.jl models.
https://github.com/cesaraustralia/DynamicGridsInteract.jl
It has a few bugs righ not but you can see how we build the interfaces for atom, electron and served to the web.
There are also a few manual model-fitting interfaces in GrowthMaps.jl:
https://github.com/cesaraustralia/GrowthMaps.jl/blob/master/src/fit.jl
Were you can manually fit models to maps or plotted curves.
The thing you may find confusing is that everything is general - there are no specific sliders being generated in these packages, instead the interfaces are for arbitrary composed models. We use Flatten.jl and FieldMetadata.jl to flatten composite objects down to tuples that you can make sliders from.