Hi Gabor and welcome!!
I will feedback quickly on the front-end, since I don’t use Stripe so I can’t really test the functionality . And I will focus on the negatives, because I think that’s more helpful if you want to improve. These are all subjective notes of course, but taking some of the following ideas, I’ve been able to increase e.g. conversion rates and engagement on my own website.
I really do think the sales page needs a bit of work - I know it sucks to read that, but I also heard it a few times for my website, and since I couldn’t really afford a designer, I started learning more about design & typography & “web psychology” and this gave me the tools to work on the user experience.
To start out, I would suggest to
- just use Bootstrap for the theme (once you feel confident enough about the design, you can try other things) [http://getbootstrap.com/]
- use much shorter texts (it’s just a LOT of bullet points - it should be directly visible after 2 seconds on the webpage what the user can get out of your app), people don’t read on the web, they scan
- perhaps the safety of the app should be very visible e.g. perhaps instead of “Connect with Stripe” it should be a “Select Package” and then on the next page you show how safe your app is (e.g. stating your CS background, etc), and THEN “Connect with Stripe”
- Also, I wouldn’t use too much “expert-language”, e.g. I would understand what “LTV/CAC ratio” means but it will take about a minute, and I wouldn’t have the patience online :-). A sentence directly at the beginning: “Find out how much your customer is REALLY worth.” or so might be easier to digest and to get the main idea.
I really liked the book “Don’t Make Me Think” by Steve Krug, that helped me with a lot of barriers in my head :-).
Sorry to focus just on the negatives here, but I hope it helps a bit.