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

# Backend / Server-side Usage

> Use the Universal Accounts SDK in Node.js to construct and sign transactions programmatically.

The **Universal Accounts SDK** can also be used in backend environments to construct and sign transactions programmatically.

The example below demonstrates usage with ethers.js and a private key in Node.js:

```ts theme={null}
import { UniversalAccount, CHAIN_ID } from "@particle-network/universal-account-sdk";
import { Wallet, getBytes } from "ethers";

// Initialize wallet
const wallet = new Wallet("PRIVATE_KEY_OR_MNEMONIC");

// Create a Universal Account instance
const ua = new UniversalAccount({
  projectId: "UA_PROJECT_ID",
  ownerAddress: wallet.address,
  tradeConfig: {
    slippageBps: 100,      // Set slippage to 1% (100 basis points)
    universalGas: true     // Use PARTI tokens to cover gas fees
  }
});

// Create a transaction to buy $0.1 worth of ARB on Arbitrum
const tx = await ua.createBuyTransaction({
  token: {
    chainId: CHAIN_ID.ARBITRUM_MAINNET_ONE,
    address: "0x912CE59144191C1204E64559FE8253a0e49E6548" // ARB token contract
  },
  amountInUSD: "0.1"
});

// Sign and send the transaction
const result = await ua.sendTransaction(tx, wallet.signMessageSync(getBytes(tx.rootHash)));

// Log the transaction result and link to explorer
console.log("Transaction ID:", result.transactionId);
console.log("View on Explorer:", `https://universalx.app/activity/details?id=${result.transactionId}`);
```

## Next steps

<CardGroup cols="2">
  <Card title="Server-side examples repo" icon="github" href="https://github.com/Particle-Network/universal-account-example">
    Open-source server-side examples using the Universal Accounts SDK.
  </Card>

  <Card title="UniversalX Registration" icon="user-plus" href="/universal-accounts/ua-reference/web/universalx">
    Register a Universal Account on UniversalX.
  </Card>
</CardGroup>