Taking payments directly in a CUSTOM app via Stripe Checkout

[CalebKWP]

Hi,

I'm just enquiring regarding if this is an allowed approach.

Inspiration: https://vercel.com/guides/getting-started-with-nextjs-typescript-stripe 

I want to build a custom app, using NextJS, that can charge customers directly using the Stripe API.
Shopify would be used purely as a CMS to manage products/inventory/orders. At no point would Shopify handle any transactions, meaning Shopify would not incur transaction fees.

Shopify & Stripe would be connected using custom Stripe Webhooks.

Here is an example flow:

1. User visits the Shopify website
2. Custom app's NextJS frontend loads a Stripe checkout form embed
3. User enters their card info and confirms the payment
4. Custom app uses the Stripe API to charge the User
5. Custom app uses the Shopify API to create an Order set to "Payment Pending"
6. Custom app listens to Stripe Webhook callback for a successful payment
7. Custom app uses the Shopify API to set the above pending order to "Payment Complete"

Shopify is quite clear that you need to go through approval, etc to create a public app that takes custom payments. 
But I have found no mention of anything to do with payments in a private app.

tl;dr

Is it possible to take payments directly with Stripe in a custom app, and use Shopify as a CMS (meaning Shopify would not incur transaction fees)?
Or does this violate any of Shopify's terms & conditions?

Thank you.

[BallersClubKikz]

I was going to ask the same question, I wanted stripe strictly to deal with payments

[WaqasA]

Were you able to figure this out? Wondering the same thing

[CalebKWP]

I'm pretty sure it's not allowed...

After speaking with someone from Shopify Sales there would be a chance that the app could be removed on the whim of a moderator/reviewer.

There's no explicit rules I can find, but I also wouldn't be surprised if an app got deleted...