Roast an idea: adding grammar checking via SDK to any app boosts retention

Hey there! I am one of the founders of Linguix - we build AI writing assistant and now we are diving into developing our API and offering an easy way to integrate it via API. My idea, that has some proof via PoC projects by now, is that when you add grammar checking dialogues to your app, people will spend more time within it = improved retention rates. Also, those dialogues can potentially be used to promote core product features, which should improve APRS/ARPU.

What do you think? Would you be open to testing this kind of product (Grammar Check API/SDK) for free?