A couple of ideas to consider:

Include a blurb in your submission like you did here:

https://news.ycombinator.com/item?id=40234611

But maybe take the salesy-ness down a little and add a bit of technical or other interesting detail.

Think of a way to make it easier for HN readers to try - right now, there's no way to try the full thing without a credit card which is a massive barrier for most casual evaluators. Watermark but more of the full feature set could be an option, for example.