- It's left aligned, which makes it harder to use on an ultrawide, with the content in the first 1/3 of the page. Having a max-width on the main container and center aligning it would be great
- Emails are GPG signed! Even if the usefulness is small, it's a awesome feature
- Pricing seems good, but I would charge more. 3$, 8$, 15$, if following the pricing scheme you have. I know I'd be happy to pay for 15$/m for a useful service. You could also make it "pay however much you want", so it's flexible if people want to pay 5$ or 50$, and it calculate with the tiers (if over X$, use plan Y)
- It feels very responsive. Great job on having the site being very light so far
- Maybe having something like Turbolinks could be pretty cool. SPA are great because they feel instant, and with a few lines of optional JavaScript you could provide an experience which is SPA-like since the server-side rendering is so quick
- The UI looks clean and minimalistic, which is great. Featureful isn't a bad thing either if done right. I think you're on the right path though
Overall, this seems like a great project. I haven't tried the builds system yet, but I definitely will. Keep up the great work Drew!