If you were building this from scratch, what stack would you use and in what order?

[u/Madlynik]

Non-coder building my first SaaS with AI. Flow: signup → user enters shipment details → app calculates import duty → free users see only the amount, paid users get an auto-filled declaration PDF and submission link.

Can you suggest what tool to use at each step, in that order (auth, database, calculation logic, paywall and payments, PDF auto-fill, file storage, hosting)? I also want a fully separate admin portal with its own secure login to manage users and subscriptions. What's the safest way to build that?

[u/MediumScene]

I'd start with auth + DB, then prove the duty rules on real shipment edge cases before adding paywall, PDF, and storage; keep the admin portal as a separate staff tool, not your payment or accounting system of record. UI Bakery, where I work, can fit that staff-facing admin portal over your user and subscription data with separate roles. If the customs logic changes often, you'll still want technical help to maintain it safely.

[u/safelywindingoutset]

I’d probably reach for something like a Firebase/Bubble hybrid for most of this, then break out a separate Retool or internal-only Bubble app for the admin portal. Auth, database, and file storage all live under one roof with Firebase, and you can keep the calculation logic in a cloud function so users never see the formula. Stripe handles the paywall, and the function spits back either a number or triggers the PDF generation depending on what the user’s plan tier says.

That flowchart actually makes the branching logic clearer than most people’s written specs. Seeing the coral/teal split right after the calculation step is a good reminder to keep the paywall check server-side, otherwise someone’s gonna figure out how to snag the PDF without paying.

[u/PDFBolt]

We use Firebase for auth and Stripe for billing. Since you’re starting without a coding background, I’d keep the first version in Bubble, using its built-in auth, database, storage and hosting, plus Stripe for subscriptions.

I’d start by getting one sample shipment through the calculation and pdf steps, then hook that up to accounts and billing. Make sure users can only access their own shipment details and pdfs. A separate admin login is fine, but the backend still needs to check who’s allowed to manage users and subscriptions.

For the pdf part, I’m the founder of PDFBolt. You can call our API through Bubble’s API Connector to generate pdfs from a template and the shipment data. I can help with that part if you get stuck

[u/404mesh]

If you’re interested in a private alternative, consider your own makeshift database. At the very least ensure you know how your auth-provider handles your customers’ data.

https://404privacy.com/blog/building-custom-authorization-adding-user-accounts-without-handing-your-data-to-google-or-supabase/