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

> ## Agent Instructions
> Before reading these docs, install the relevant Circle Skill to get pre-loaded context — skills are LLM-optimized and cover architecture decisions, correct flows, and common pitfalls. In Claude Code: run /plugin marketplace add circlefin/skills then /plugin install circle-skills@circle. With Vercel Skills CLI: run npx skills add circlefin/skills. Available skills: use-usdc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md (balances, transfers, approvals on EVM and Solana); EURC has no skill — see https://developers.circle.com/stablecoins/what-is-eurc.md; bridge-stablecoin https://github.com/circlefin/skills/blob/master/plugins/circle/skills/bridge-stablecoin/SKILL.md (crosschain transfers via CCTP, USDC, EURC, and third-party assets); use-arc https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md (Arc chain config, contract deployment, USDC bridging — Arc docs: https://docs.arc.io/llms.txt); use-circle-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md (choose wallet type); use-developer-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md (custodial wallets for payouts and treasury); use-user-controlled-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md (embedded wallets with Web2 login); use-modular-wallets https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md (smart contract wallets with passkeys and ERC-4337); use-gateway https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md (unified USDC balance, nanopayments); use-smart-contract-platform https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md (deploy, interact, monitor contracts). Pair any skill with the Circle MCP server for live SDK signatures, contract addresses, and chain IDs: {"mcpServers":{"circle":{"url":"https://api.circle.com/v1/codegen/mcp"}}}.
> Read the product overview first. Each product has an overview explaining when and why to use it. Read it before quickstarts.
> Pick the right wallet type. Developer-controlled (you hold keys), user-controlled (end user holds keys via PIN/social login), or modular (smart contract wallets with passkeys). See https://developers.circle.com/wallets.md.
> Use CCTP V2 for crosschain transfers. CCTP natively transfers USDC and EURC via burn-and-mint, and supports permissionless wrapping of third-party assets via lock-and-mint. V1 is legacy; always use V2 unless V1 is specified or the chain requires it (Noble, Sui, and Aptos still require V1). Migration guide: https://developers.circle.com/cctp/migration-from-v1-to-v2.md.
> Use Bridge Kit for frontend bridging. Wraps CCTP with a simpler SDK for user-facing apps. Use CCTP directly for backend transfers.
> Gas Station vs Paymaster. Gas Station sponsors gas for Circle Wallet transactions. Paymaster lets users pay gas in USDC. Different use cases — read both overviews.
> Gateway Nanopayments for sub-cent payments. Gasless USDC micropayments down to $0.000001 via x402 and batched settlement. For pay-per-request APIs, AI agent payments, streaming.
> Look up USDC addresses per chain. Never hardcode — use https://developers.circle.com/stablecoins/usdc-contract-addresses.md.
> Prefer SDKs over raw API calls. Node.js and Python SDKs handle auth, retries, and errors.
> API key required. Bearer token in Authorization header. Testnet and mainnet use separate keys and may use different base URLs depending on the product.
> Set up webhooks when available. Most operations are async. Webhooks deliver transaction confirmations and state changes.
> When calling list endpoints, paginate using pageSize and pageAfter until no nextPageAfter cursor is returned—stopping at the first page silently misses records.
> Building an AI agent? Start with the Agent Stack—Circle CLI, agent wallets, and nanopayments built for autonomous use cases: https://developers.circle.com/agent-stack.md.

# Quickstart: Set up a USDC trustline on XRPL

This guide shows you how to set up a trustline for USDC on the XRPL Testnet
using TypeScript. You'll use the XRPL JavaScript SDK to:

* Create and fund a wallet
* Establish a trustline with the USDC issuer
* Prepare the wallet to receive USDC

## Prerequisites

Before you begin, ensure you have the following:

* [Node.js 16 or later](https://nodejs.org/)
* A terminal or code editor

## Part 1: Set up your project

Perform the following steps to set up your project.

### 1.1. Create a project directory

Run the following commands to create and initialize your project:

```shell Shell theme={null}
mkdir xrpl-usdc-trustline
cd xrpl-usdc-trustline
npm init -y
```

### 1.2. Install dependencies

Run the following command to install the required libraries:

```shell Shell theme={null}
npm i xrpl typescript ts-node
```

## Part 2: Configure your project

Perform the following steps to configure your project.

### 2.1. Update the `package.json` file

Open your `package.json` file and make the following updates:

* Remove the `"type": "commonjs"` line if it was automatically added.
* Add or update the `start` script to use `ts-node` to run your `main.ts` file.

Your updated `package.json` should look similar to the following:

```json package.json theme={null}
{
  "name": "xrpl-usdc-trustline",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "ts-node main.ts"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "ts-node": "^10.9.2",
    "typescript": "^5.8.3",
    "xrpl": "^4.2.5"
  }
}
```

### 2.2. Add a `tsconfig.json` file

Create a `tsconfig.json` file with the following configuration:

```json tsconfig.json theme={null}
{
  "compilerOptions": {
    "target": "ES2020",
    "module": "CommonJS",
    "lib": ["ES2020"],
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "outDir": "./dist",
    "rootDir": "./"
  },
  "include": ["*.ts"],
  "exclude": ["node_modules"]
}
```

## Part 3: Write your app code

Create a `main.ts` file and paste the following code:

```ts theme={null}
import {
  Client,
  IssuedCurrencyAmount,
  TransactionMetadata,
  TrustSetFlags,
  Wallet,
} from "xrpl";

const USDC: IssuedCurrencyAmount = {
  currency: "5553444300000000000000000000000000000000",
  issuer: "rHuGNhqTG32mfmAvWA8hUyWRLV3tCSwKQt",
  value: "1000000000",
};

async function main() {
  const client = new Client("wss://s.altnet.rippletest.net:51233");
  await client.connect();

  try {
    // Creating and funding a user wallet
    console.log("Creating and funding a user wallet...");
    const userWallet = Wallet.generate();
    await client.fundWallet(userWallet);

    console.log("======= User wallet details =======");
    console.log("Address:", userWallet.address);
    console.log("Seed:", userWallet.seed);
    console.log("NOTE: DO NOT SHARE THE SEED WITH ANYONE!");
    console.log("===================================");
    console.log("");

    // Creating a trustline for USDC
    console.log("Creating a trustline for USDC...");
    const response = await client.submitAndWait(
      {
        TransactionType: "TrustSet",
        Account: userWallet.address,
        LimitAmount: USDC,
        Flags: TrustSetFlags.tfSetNoRipple,
      },
      { autofill: true, wallet: userWallet },
    );

    if (
      response.result.validated &&
      (response.result.meta as TransactionMetadata).TransactionResult !==
        "tesSUCCESS"
    ) {
      throw new Error(`Transaction failed: ${JSON.stringify(response)}`);
    }

    console.log(
      `Transaction succeeded: https://testnet.xrpl.org/transactions/${response.result.hash}`,
    );

    // Receiving USDC
    console.log("Receiving USDC...");
  } finally {
    await client.disconnect();
  }
}

main().catch(console.error);
```

## Part 4: Run your application

Run the following from your project folder:

```shell Shell theme={null}
npm start
```

After you run the script, the terminal should display your wallet's public
address, the wallet seed, and a transaction link that confirms the successful
creation of the trustline. Your wallet is now ready to receive USDC on the XRPL
Testnet.