There are weweb.io and flutterflow.io that support code export for the frontend if that is what you are looking for. Source: 12 months ago

WeWeb + Xano for backend. I am from WeWeb and will gladly answer any questions you might have. Source: about 1 year ago

WeWeb. You can export clean code AND self-host the application on your infrastructure. Source: about 1 year ago

WeWeb + Xano for backend. They both have a nice Stripe integration that allow you do what you describe. Source: about 1 year ago

If you are interested in learning Weweb, start here: https://academy.weweb.io/. Source: about 1 year ago

Here is my product: https://matchkraft.com/. It is a marketing toolkit. I think you need to ask for feedback, asking why users don't want to pay for a premium subscription. So far, you are getting new users that is a good sign you are going to the right direction. Maybe, who is your ideal customer or maybe your product is ok but need more visibility (maybe paying ads). Try to get active users. I really want to... Source: 12 months ago

Calling a 3rd party API: There is a complete ecosystem providing "google-sheets-as-DB". I personally tested and recommend https://sheetson.com/ but there are a lot more with free tiers https://sheetsu.com/ https://sheety.co/. Source: about 2 years ago