Ask HN: Building Great Embedded Web Apps?

I’m building a web app that will primarily be embedded on my clients websites in an iframe or by other means. I am looking for articles, guides, or talks on best practices for building embedded web apps. Does anyone have any suggestions?

Some issues I’m encountering: - Building UI's with no scrolling - Responsive design within iframes - Testing different scenarios my iframe might be in

I really like Typeform’s embedded forms. Anyone have other products which have really good embedded functionality?