I am Developing a SharePoint Extension web part for O365. The purpose of the web part is to allow the user to click on a letter of the alphabet and then through the search API return all the items with a title that begins with the selected letter.
I have figured out how to use the search API for finding keywords:
/_api/search/query?querytext='sharepoint'
But I don't know how to use the API to get all items that begin with a certain letter. I have tried googling an answer for this but haven't found anything. Is what I am trying to do even possible?