Hmm If I were to design this... I would make it so that you don't have to replace the entire data source each time... I think a "suggestion" entry in the data source should be represented as it's own entity in the API...

e.g

instead of PUT /api/datasource/<UUID> overriding the entire datasource each time..

allow an api user to insert lines of text or rich objects.

POST /api/datasource/<UUID>/suggestion

  {
   ...
  }

or support bulk insertion.

POST /api/datasource/<UUID>/suggestion

  [
      { ...
      },...
  ]

This works better for scaling when you can't just replace all suggestions in one request (like an ETL like operation for a very large dataset). Then you can also allow for updating single "suggestion" entities without replacing the whole dataset.

I also think you should support rich objects, allow for things like boosting rules, different templates for object types, spelling correction, synonyms. I think this type of service would be really useful.

Same for Android chrome.

Can I use that as description for the service? :)