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

# CDP Paymaster Quickstart

This quickstart shows how to sponsor gas for transactions using **CDP user wallets** with smart accounts on Base. By the end, you'll have a working example of gasless transactions.

<Info>
  This guide uses CDP user wallets. For other integration patterns, see the [Guides](/paymaster/guides/quickstart) section.
</Info>

## Prerequisites

* A [CDP account](https://portal.cdp.coinbase.com) with an active project
* Node.js 22+ and npm/pnpm/yarn
* Basic familiarity with React and TypeScript
* Your app domain [allowlisted](/embedded-wallets/domains) in CDP Portal

## Step 1: Configure Paymaster in CDP Portal

1. [Sign in](https://portal.cdp.coinbase.com) to your CDP account
2. Navigate to [Paymaster](https://portal.cdp.coinbase.com/products/bundler-and-paymaster) under **Onchain Tools** in the left-nav
3. Select **Base Sepolia** in the network dropdown (top right of the configuration panel)
4. Under **Configuration**, add any contracts you want to sponsor to the allowlist

<Warning>
  **Security:** Your Paymaster endpoint URL contains your Client API Key. While not as sensitive as a Secret API Key, exposing it allows others to consume your gas credits.

  **Always use one of these secure integration methods:**

  * **CDP user wallets** — Use `useCdpPaymaster: true` (shown below)
  * **CDP API key wallets** — Use [Managed Mode](/wallets/using-wallets/send-transactions#network-scoped-accounts#paymaster-integration)
  * **Other wallets (Wagmi, viem)** — Create a [Paymaster Proxy](/paymaster/guides/paymaster-proxy)

  Never expose the raw Paymaster URL in client-side code.
</Warning>

## Step 2: Set up a user wallet with Smart Accounts

Install the CDP SDK packages:

```bash theme={null}
npm install @coinbase/cdp-core @coinbase/cdp-hooks
```

Configure the provider to create smart accounts for new users:

```tsx title="App.tsx" theme={null}
import { CDPHooksProvider } from "@coinbase/cdp-hooks";

function App() {
  return (
    <CDPHooksProvider
      config={{
        projectId: "your-project-id",
        ethereum: {
          createOnLogin: "smart", // Creates smart accounts for AA features
        }
      }}
    >
      <YourApp />
    </CDPHooksProvider>
  );
}
```

## Step 3: Send a Sponsored Transaction

Use `useSendUserOperation` with `useCdpPaymaster: true`. This is the recommended approach — it handles Paymaster integration securely without exposing your endpoint URL:

```tsx title="SponsoredTransaction.tsx" theme={null}
import { useSendUserOperation, useCurrentUser } from "@coinbase/cdp-hooks";
import { encodeFunctionData } from "viem";

// Example: ERC-20 transfer ABI
const erc20Abi = [
  {
    name: "transfer",
    type: "function",
    stateMutability: "nonpayable",
    inputs: [
      { name: "to", type: "address" },
      { name: "value", type: "uint256" },
    ],
    outputs: [{ name: "", type: "bool" }],
  },
] as const;

function SponsoredTransaction() {
  const { sendUserOperation, status, data, error } = useSendUserOperation();
  const { currentUser } = useCurrentUser();

  const handleSend = async () => {
    const smartAccount = currentUser?.evmSmartAccounts?.[0];
    if (!smartAccount) return;

    const result = await sendUserOperation({
      evmSmartAccount: smartAccount,
      network: "base-sepolia",
      calls: [{
        to: "0x036CbD53842c5426634e7929541eC2318f3dCF7e", // USDC on Base Sepolia
        value: 0n,
        data: encodeFunctionData({
          abi: erc20Abi,
          functionName: "transfer",
          args: ["0xRecipientAddress", 1_000_000n], // 1 USDC (6 decimals)
        }),
      }],
      // Use CDP's built-in Paymaster (Base only)
      useCdpPaymaster: true,
    });

    console.log("Transaction hash:", result.transactionHash);
  };

  return (
    <div>
      <button onClick={handleSend} disabled={status === "pending"}>
        {status === "pending" ? "Sending..." : "Send Sponsored Transaction"}
      </button>
      
      {status === "success" && data && (
        <p>Success! Tx: {data.transactionHash}</p>
      )}
      
      {status === "error" && (
        <p>Error: {error?.message}</p>
      )}
    </div>
  );
}
```

## Step 4: Verify It Works

1. Start your development server
2. Sign in to create a smart account
3. Click the button to send a sponsored transaction
4. Check the [Paymaster Logs](https://portal.cdp.coinbase.com/products/bundler-and-paymaster) in CDP Portal to see your sponsored transaction

## Batch Multiple Calls

Smart accounts can execute multiple calls atomically in a single user operation:

```tsx theme={null}
const result = await sendUserOperation({
  evmSmartAccount: smartAccount,
  network: "base-sepolia",
  calls: [
    { to: contractA, value: 0n, data: callDataA },
    { to: contractB, value: 0n, data: callDataB },
    { to: contractC, value: 0n, data: callDataC },
  ],
  useCdpPaymaster: true,
});
```

All calls execute in order. If any call fails, the entire operation reverts.

## Next Steps

* **[Security](/paymaster/reference-troubleshooting/security)** — Learn about protecting your Paymaster endpoint
* **[FAQs](/paymaster/faqs)** — Common questions about billing, Account Abstraction, and EIP-7702
* **[Paymaster Proxy Guide](/paymaster/guides/paymaster-proxy)** — Detailed guide on implementing a production proxy
* **[Examples Repository](https://github.com/coinbase/paymaster-bundler-examples)** — More integration examples with various SDKs