App Kit SDK: Borrow

How it works

A user supplies cirBTC as collateral and receives USDC in return, all in a single atomic transaction on Arc. If you subscribe to webhooks, the SDK posts events when a loan’s health changes, so you can prompt the user to act before liquidation.

For how loan health is measured and when a position becomes liquidatable, see How loan health works.

Quick look

This code snippet opens a loan by borrowing 1,000 USDC against cirBTC on Arc Testnet:

TypeScript

const result = await kit.borrow.borrow({
  from: { adapter: viemAdapter, chain: "Arc_Testnet" },
  marketId:
    "0x1111111111111111111111111111111111111111111111111111111111111111",
  borrowAmount: "1000.0",
});

For a complete end-to-end flow, follow the Originate a loan quickstart.

Installation

Install the App Kit SDK to use Borrow. If you only need to borrow and don’t want to install the full App Kit SDK, install the standalone Borrow Kit for your preferred adapter:

Borrow writes require an adapter with atomic-batch support. Use Viem or Circle Wallets.

Viem
Circle Wallets

npm install @circle-fin/borrow-kit @circle-fin/adapter-viem-v2 viem

yarn add @circle-fin/borrow-kit @circle-fin/adapter-viem-v2 viem

npm install @circle-fin/borrow-kit @circle-fin/adapter-circle-wallets

yarn add @circle-fin/borrow-kit @circle-fin/adapter-circle-wallets

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Borrow

App Kit SDK: Borrow

How it works

Quick look

Installation

​How it works

​Quick look

​Installation

How it works

Quick look

Installation