Ask HN: Best framework/stack for simple SaaS product site with payment

I just built out a chrome extension client, and am now setting up the server. I could build everything from scratch in notepad, but there must be a far more efficient stack/framework for this.

Here's what I'm trying to achieve:

* webapp for people to sign up (with email verification), get an API token (probably a uuid?), and to purchase a monthly/annual subscription to my service.

* ability to remember low frequency data (user info) vs high write/read rate frequency such as how often they are hitting my apis (once a second per person). I was going to use MySQL for some data and redis for things that need to be referenced every api call such as updating the call count and checking membership status to ensure the api request should be fulfilled.

Here's what I've done and am planning:

* host a static index.html with the landing page, not sure where I can get a minimal theme. Might just view-source and copy someone's design.

* use stripe integration to manage payments so my hands aren't dirty

* not sure how to do session management so users can login and purchase a subscription.

* host that on vercel along with my serverless functions / lambdas for the client communication.

* everything is written in node.js. client side is written in react and blueprint.

Sorry if this is a little haphazard, I haven't slept in two days. Thank you for your time!