InAppStory - Engage your customers with Stories right from your app or mobile web product with InAppStory.
Buffer Stories Creator - Quickly create thumb-stopping content for Stories
Storyly - Bring superb stories to your app
How-To Story Creator - The simple creator tool for ‘how-to’ stories
Zuck.js - JavaScript library that lets you add Stories everywhere
Pablo - Pablo enables any user to create engaging images without sign-in and design experience.