# Technical architecture

### Connecting to Yumi Credit Line

* The underwriting process is facilitated via **dedicated API endpoints** or **SDK methods** (TBD). Your system sends us users' **banking** and **wallet** data, along with any **available data**. We use it to **analyze the user's profile** and determine a credit limit.&#x20;
* Required data includes one or more **financial sources** (bank, wallet, or card), the **user's legal name**, **nationality,** and one or more **points of contact**.
* For cards with the **Mobile app**, we also plan to build a **React Native SDK** for modular integration.

After onboarding, an initial **limit is dynamically updated** based on users' and macroeconomic data.

### Loan Authorization (Per-Transaction Decision)

The card queries the API for a decision (**loan authorization**); the API returns a response with the current credit limit, approval (or rejection), and additional loan information. The model is **just-in-time underwriting**: users' **limit is checked for each purchase**; the limit may change from transaction to transaction and after repayments.

**Funding model** at authorization: the card receives the server-side **allowance signature** to withdraw funds from the Yumi hot vault, without waiting for a transfer, thereby avoiding additional **transaction delays**.

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### Debt Repayment

There are dedicated **API endpoints** for **constructing** and **submitting** a **repayment tx**. Also, if users want to repay debt from a 3rd-party account, they can **send an ochain transaction** directly to the **dedicated wallet** or **provide us a signature** via API endpoint. We can execute the transaction on our side.
