From BaaS to Modular Card Stacks

This is why BaaS often becomes a starting point, not a permanent home. Early on, a fintech wants a ready made stack that gets cards live fast and handles bank coordination, compliance setup, and basic program design. As volume grows, the company usually wants direct bank access, tighter KYC and AML rules, new products like charge or credit, and more control over physical cards, ledgering, and economics.

• A mediated BaaS relationship works like buying a suit off the rack. The provider has already chosen the sponsor bank, processor, compliance flow, and operating playbook, which is why launch speed is high but customization is narrower.
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• The move usually happens when the card program stops being a side feature and becomes core infrastructure. That is when fintechs want to launch a second product, tune underwriting or KYC logic, support bespoke physical card needs, or negotiate more directly with the sponsor bank.
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• There is a second path beyond switching to a modular processor like Lithic. Companies at larger scale can also internalize more of the stack, as Brex did, because direct network and bank relationships can unlock faster roadmap control, wider country coverage, and more ownership of fraud, credit, and capital workflows.
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Going forward, the winners in card issuing will be the providers that let customers graduate without ripping everything out. The market is moving toward modular stacks where companies start with speed, then peel back layers as card programs become more strategic, regulated, and tightly woven into the product itself.