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

# Backend Integration

## Sample Project

[https://github.com/Privacy-Cash/privacy-cash-sdk/blob/main/example/](https://github.com/Privacy-Cash/privacy-cash-sdk/blob/main/example/)

## Installation

```bash theme={null}
npm install privacycash --save
```

<Info>
  Requires **Node.js 24+**. The SDK is written in TypeScript and includes type definitions.
</Info>

## Initialization

```typescript theme={null}
import { PrivacyCash } from 'privacycash'

const client = new PrivacyCash({
  RPC_url: 'YOUR_SOLANA_MAINNET_RPC_URL',
  owner: 'YOUR_PRIVATE_KEY',
  enableDebug: false // optional
})
```

### Supported Private Key Formats

```typescript theme={null}
// Base58 encoded string
const client1 = new PrivacyCash({
  RPC_url: 'https://...',
  owner: '5Jd7...' // Base58 string
})

// Byte array
const client2 = new PrivacyCash({
  RPC_url: 'https://...',
  owner: [1, 2, 3, ...] // number[]
})

// Uint8Array
const client3 = new PrivacyCash({
  RPC_url: 'https://...',
  owner: new Uint8Array([1, 2, 3, ...])
})

// Solana Keypair object
import { Keypair } from '@solana/web3.js'
const client4 = new PrivacyCash({
  RPC_url: 'https://...',
  owner: Keypair.generate()
})
```

## Interacting with Privacy Cash

Once above steps are done, client can query [balance](/sdk/balance), make [deposits](/sdk/deposit) and [withdrawals](/sdk/withdraw).