Marqeta is a card issuing and payment processing platform. Businesses use Marqeta to launch and manage debit, prepaid, and credit card programs — for their customers or employees — without building their own payments infrastructure. Marqeta sits in the payment stack as an issuer processor: when a cardholder swipes a card issued on Marqeta's platform, Marqeta connects to card networks like Visa and Mastercard and issuing bank partners to authorize the transaction in real time. Marqeta's key technical differentiator is Just-in-Time (JIT) Funding, which lets customers apply real-time business logic to authorize or decline transactions at the moment they occur. Marqeta's customers are primarily fintechs and non-financial companies pursuing embedded finance — gig economy platforms, BNPL providers, neobanks, and corporate card platforms. Marqeta earns interchange fees on every card transaction processed through its platform, sharing a portion back with customers and paying network and bank fees, with net revenue and gross profit representing what remains. Revenue scales with total payment volume (TPV). Marqeta is expanding into credit cards, value-added services like fraud decisioning and rewards management, and European markets, where it acquired TransactPay to gain an e-money institution license covering the UK and EEA. Block, which includes Cash App and Afterpay, represents roughly 44-46% of net revenue, though that concentration has been declining as non-Block customers grow faster.