How to build an invoicing app for iOS
What an invoicing app needs
- A client list and an item or rate catalog
- An invoice builder with line items, tax, and totals
- PDF generation and sharing by email or message
- Status tracking: draft, sent, paid, overdue
- A payment link so clients can pay the invoice (Stripe)
- Sync and backup so invoices are not stuck on one device (Supabase)
The MVP slice is: create an invoice, generate a PDF, and mark it paid. Recurring invoices, multi-currency, and automatic reminders come later.
Core screens and data
An invoicing app needs a client list, an item catalog, an invoice builder, an invoice list with status, an invoice detail with a PDF, and a business settings screen. Here is what each screen does and the data behind it.
| Screen | What it does | What it stores |
|---|---|---|
| Client list | Manages who gets invoiced | Client name, email, address, tax id |
| Item catalog | Holds reusable services and rates | Item name, default rate, unit |
| Invoice builder | Adds line items, tax, and totals | Line items, quantities, rates, tax rate, total |
| Invoice list | Tracks each invoice's status | Status draft, sent, paid, overdue, issue and due dates |
| Invoice detail and PDF | Views and shares the invoice | Invoice number, PDF layout, payment status |
| Payment link | Lets a client pay the invoice | Stripe reference, amount, paid timestamp |
| Business settings | Sets branding and defaults | Business info, logo, currency, default tax |
Starter prompt
This is the plain-English prompt you paste into AppFlight to build the first version. AppFlight reads it, plans the screens, and generates native Swift you can run in the live simulator and then refine in plain language.
Build an invoicing app for freelancers. Users keep a list of clients with contact and tax details, plus a catalog of reusable items with default rates. An invoice builder lets them add line items, apply a tax rate, and see the total, then generate a branded PDF they can send by email or message. An invoice list tracks each invoice as draft, sent, paid, or overdue, with issue and due dates. Store clients, items, and invoices in Supabase so records sync and survive a new phone. Attach a Stripe payment link to each invoice so clients can pay for real-world work, kept separate from the app's own subscription. Charge users a monthly subscription for unlimited invoices, their own logo, and reminders through a RevenueCat paywall using in-app purchase.
How to build it with AppFlight
Describe it, for example: "An invoicing app where I add clients, build an invoice with line items and tax, generate a PDF, send it, and track whether it is paid or overdue." AppFlight plans the screens, generates native SwiftUI, and runs it in a live simulator. Use the Supabase connector for storage and accounts, and the Stripe connector to attach a payment link so clients can pay. You iterate by asking for changes in plain language.
Monetization for an invoicing app
The app makes money as a subscription: unlimited invoices, your logo, reminders. That is a digital upgrade unlocked inside the app, so it goes through in-app purchase with RevenueCat. Separately, the payments your users collect from their own clients are for real-world goods and services, so those run through Stripe and are not subject to in-app purchase. Keep the two flows distinct so review goes smoothly.
Shipping it to the App Store
When it works in the simulator, AppFlight signs the build, uploads to TestFlight so you can test a real invoice and payment link, then submits to the App Store with metadata and screenshots. If Apple rejects the build, AppFlight reads the reason, fixes it, and resubmits. Apple reviews every app, so a submission is not the same as an approval, but the pipeline runs without you opening Xcode.
FAQ
Does an invoicing app have to use in-app purchase for payments?
No. The invoices your users send are for real-world goods and services, so client payments run through Stripe. In-app purchase only applies to the app own subscription.
Can it generate PDF invoices?
Yes. SwiftUI and PDFKit can render and share a PDF. AppFlight builds the invoice layout and the share flow in native Swift.
Do I need an account system?
For sync and backup, yes. AppFlight connects Supabase so invoices and clients are stored server-side and survive a new phone.