> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arc.io/llms.txt
> Use this file to discover all available pages before exploring further.

# App Kit SDK: Unified Balance

> Create a chain-agnostic USDC balance and spend it instantly on any blockchain with the App Kit SDK's Unified Balance capability.

The [App Kit SDK](/app-kit) includes the Unified Balance capability that
combines USDC from multiple blockchains into a single, instantly spendable
balance. It is built on top of
[Circle Gateway](https://developers.circle.com/gateway) and abstracts the
Gateway workflow so that cross-ecosystem spends (for example, EVM → non-EVM) are
as straightforward as same-ecosystem spends (for example, EVM chain → another
EVM chain).

## How it works

Unified Balance works by depositing funds held across multiple blockchains into
a single, chain-agnostic Unified Balance. Those funds are then available to
spend instantly on any blockchain.

The process is illustrated below:

```mermaid theme={null}
flowchart LR
  A[Chain A wallet] -->|"deposits funds"| UB[(Unified Balance)]
  B[Chain B wallet] -->|"deposits funds"| UB
  C[Chain C wallet] -->|"deposits funds"| UB
  UB -->|"spends funds"| D[Chain D wallet]
```

## Quick look

This code snippet creates a Unified Balance by depositing funds from two
blockchains to spend on a third:

```typescript TypeScript theme={null}
// Deposit 1.00 USDC into the Unified Balance from Base
const depositBase = await kit.unifiedBalance.deposit({
  from: { adapter: viemAdapter, chain: "Base_Sepolia" },
  amount: "1.00",
  token: "USDC",
});
// Deposit 1.00 USDC into the Unified Balance from Arbitrum
const depositArb = await kit.unifiedBalance.deposit({
  from: { adapter: viemAdapter, chain: "Arbitrum_Sepolia" },
  amount: "1.00",
  token: "USDC",
});
// Spend 1.50 USDC from the Unified Balance on Arc
const spendResult = await kit.unifiedBalance.spend({
  amount: "1.50",
  from: { adapter: viemAdapter },
  to: {
    adapter: viemAdapter,
    chain: "Arc_Testnet",
    recipientAddress: "0xRecipientAddress",
  },
});
```

For a complete end-to-end flow, follow the quickstart for your scenario:

* [Deposit and Spend a Unified Balance](/app-kit/quickstarts/unified-balance-deposit-and-spend)
* [Use a Delegate to Deposit and Spend a Unified Balance](/app-kit/quickstarts/unified-balance-delegate-deposit-and-spend)

## Installation

[Install the App Kit SDK](/app-kit/tutorials/installation) to use Unified
Balance. If you only need Unified Balance and don't want to install the full App
Kit SDK, follow the steps below to install the standalone Unified Balance Kit.

<Steps>
  <Step title="Install Unified Balance Kit">
    <CodeGroup>
      ```bash npm theme={null}
      npm install @circle-fin/unified-balance-kit
      ```

      ```bash yarn theme={null}
      yarn add @circle-fin/unified-balance-kit
      ```
    </CodeGroup>
  </Step>

  <Step title="Install adapters">
    Install the [adapters](/app-kit/tutorials/adapter-setups) you need for the
    blockchains you plan to deposit from and spend on.

    <Tabs>
      <Tab title="Viem">
        <CodeGroup>
          ```bash npm theme={null}
          npm install @circle-fin/adapter-viem-v2 viem
          ```

          ```bash yarn theme={null}
          yarn add @circle-fin/adapter-viem-v2 viem
          ```
        </CodeGroup>
      </Tab>

      <Tab title="Ethers">
        <CodeGroup>
          ```bash npm theme={null}
          npm install @circle-fin/adapter-ethers-v6 ethers
          ```

          ```bash yarn theme={null}
          yarn add @circle-fin/adapter-ethers-v6 ethers
          ```
        </CodeGroup>
      </Tab>

      <Tab title="Solana">
        <CodeGroup>
          ```bash npm theme={null}
          npm install @circle-fin/adapter-solana-kit @solana/kit @solana/web3.js
          ```

          ```bash yarn theme={null}
          yarn add @circle-fin/adapter-solana-kit @solana/kit @solana/web3.js
          ```
        </CodeGroup>
      </Tab>

      <Tab title="Circle Wallets">
        <CodeGroup>
          ```bash npm theme={null}
          npm install @circle-fin/adapter-circle-wallets
          ```

          ```bash yarn theme={null}
          yarn add @circle-fin/adapter-circle-wallets
          ```
        </CodeGroup>
      </Tab>
    </Tabs>
  </Step>
</Steps>