Mobile Invoice App With Tipalti Integration

I need a straightforward mobile app that lets me create Tipalti-ready invoices on the go and immediately route those payments through my Wells Fargo debit account. Every week I work within a fixed spending limit set by the bank, so the app must reference that cap before an invoice is approved and sent.

Core flow I’m after:
• I open the app, enter or pull in customer details, and generate a branded invoice.
• The invoice automatically carries the correct Tipalti fields so it can be processed without manual re-entry.
• When I hit “send”, the app checks my available Wells Fargo debit balance against the weekly limit and confirms funds are available.
• Once cleared, the payment instruction pushes straight to Tipalti and the invoice status updates to “paid” in the app.

Essential requirements
• Native or cross-platform build for iOS and Android.
• Secure connection to my Wells Fargo account (OAuth or API) so the balance check is real-time.
• Local and cloud data encryption for all customer and transaction information.
• A lean dashboard that shows outstanding, scheduled, and paid invoices at a glance.
• Source code, build files, and a brief hand-off guide delivered at completion.

Nice-to-have (but not mandatory): push notifications on balance changes, dark-mode UI, and simple CSV export.

If you’ve integrated Tipalti before or worked with banking APIs, tell me how you handled authentication and data security, then outline a rough timeline for getting a first test build in my hands.