I saw similar tools as browser extensions, but I think it's quite smart to package this for the website owners to buy & install. This way, it's more clear how to monetise and sustain this. Have you considered packaging this as a browser extension?
I used the extension before called Survol, it was quite nice. But it only showed the description & thumbnail of the hyperlink. I think showing linked text or embed on click in the overlay is useful! Great job on the execution!
Yes I explored the browser extension direction, but the business model & our cost-per-link-preview-generation does not work yet. Making the website owner to pay for it makes the business math work much better.