In software development never assume anything. Software development is hard and assumptions can catch you out very quickly. Remember the old phrase - assume makes an ass out of u and me.
I'm a freelance web developer and I use Expirify all the time (not with Let's Encrypt SSL certificates) to track all my clients' domain and SSL renewals and it works great
On visiting the website I could not understand what you did.
Move this text above the fold and use as main text:
(Header) Turn emails into usable data
(Lead Text) Emails are full of valuable data critical to businesses. Unfortunately emails are just unstructured text. Parseur is an email parser that lets you easily transform email content into usable structured data.
I would pay if it would speed up the recruitment process, as I hate not having an answer to my applications. The 'We will contact you within 7 working days' or 'If you haven't heard from us in 14 days consider your application unsuccessful' automated responses have to end.
Also, if I could be guaranteed completely honest and helpful feedback on any rejection.
Not just "not the right experience", but "we need someone who has built a product with xyz framework", or "looking for someone who has had a bigger leadership role before".
I have absolutely nothing against Ruby but it seems that in general people already think that it's not hip so very little new projects are being made with it. Node is the new "hip" thing currently, not Ruby.
I just resurrected a side project web app from a few years ago that is completely automated, but it is not very complicated so it probably doesn't count as your defined medium-sized web app.
I have no user registration for one thing, as my side project doesn't really need it and I hate having to register on sites to do the simplest things.
I do still check the web app about once a month for about an hour, just to run a check on things and make updates if needed, like changes to marketing copy.
I pay for code reviews in the UK from a company called Atlas Computer Systems Ltd https://www.atlascode.com/
They do code reviews for startups to make sure your code is high quality and isn't building technical debt.