Open Banking, faked convincingly.
Building against real banking APIs is slow, rate-limited and risky. MockBank stands in for them — a faithful-enough simulator that let TaxFlow's linking flow be built and tested at speed.
A mock is only useful if it's honest about the shapes and failure modes of the real thing. The value was in modelling the awkward states, not just the happy path.
Tell us what you're making and where you're stuck.