I sell first before coding anything.
The video you see on the front page does not exist in code, it is simply a prototype designed with Figma (https://figma.com) and animated with Principle (https://principleformac.com). I created the landing page and video, added a Mailchimp form, and I posted on Twitter, Reddit, and here on Hacker News, the communities in which it made sense. For me, it's a productivity / task management tool, so I would post on reddit.com/r/getdisciplined or reddit.com/r/productivity.
It's all about creating a minimum viable product, as you might well be aware, but what you may not know is that an MVP need not have code. Indeed, it could be a video as I did, and I think for software, a video works best as people can actually see what it looks and feels like, without you necessarily creating the product architecture (full frontend and backend plus devops etc). Now I have over 150 subscribers in only a month due to rapid creation of this type of MVP, and based on this feedback, I changed my designs, and only now I am beginning to really create the heart of the product.
Using non-code MVPs is the best way in my opinion to sell quickly before building.