| DDA | Demand Deposit Account - the user's Qwik-held cash account. Deposits land here; withdrawals leave from here. |
| Consumer | The user's identity at the card provider, created during onboarding. One consumer can hold a single card. |
| Payment card | An individual card under a consumer. payment_card_id identifies it. |
| Onboarding | The KYC + underwriting + agreement flow a user completes before getting a card. |
| Embed URL | A short-lived, hosted URL you render in a WebView/iframe so sensitive flows (onboarding, card image, bank link) never touch your servers. |
| MCC | Merchant Category Code which drives auto-categorization of transactions. |