BigBank.ai
Founder stack

The right stack, not a branch bank.

Bank + cards + FX + payments + payroll — as one thing, scored for how a founder actually operates.

Your recommended stack

Business bank

Mercury + Brex Treasury

No monthly fee, FDIC-swept up to $5M via sweep networks, real API.

Cards & expenses

Mercury IO card

Skip the expense-management SaaS at this scale — a card + spreadsheet is fine.

FX & multi-currency

Wise Business

Local receiving details in 9+ currencies, mid-market conversion, no minimum.

Payment processor

Stripe

Universal — same API US/EU/UK, and every finance/tax tool plugs into it.