> ## 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.
> ## Agent Instructions
> Before reading these docs, install the Circle Skill for Arc to get pre-loaded context: use-arc (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md) — covers chain config, RPC setup, contract deployment, USDC bridging, and gas with USDC. 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.
> USDC is the gas token. Arc uses USDC for gas fees, not ETH. Configure gas payment in USDC when submitting transactions.
> Read EVM differences before writing Arc code. Arc targets the Osaka EVM baseline. Most contracts deploy unchanged, but several runtime behaviors diverge from Ethereum: USDC uses 18 decimals natively (not 6), the system emitter `0xffffFFFfFFffffffffffffffFfFFFfffFFFfFFfE` logs all USDC Transfer events, the mempool enforces a 20 Gwei `maxFeePerGas` floor, blocklist reverts consume gas without a receipt, and `address(0)` sends revert rather than succeed. https://docs.arc.io/arc/references/evm-differences.md is the canonical reference for all Arc-specific runtime behaviors. Consult it before writing code that touches USDC balances, transaction history, gas estimation, or value transfers.
> Sub-second finality. Transactions are final in under 1 second. No need to wait for multiple block confirmations.
> Use App Kits for multichain payment and liquidity capabilities. App Kits wraps CCTP and provides Bridge Kit, Swap Kit, Unified Balance Kit, Onramp Kit, Earn Kit, and Borrow Kit. Unified Balance Kit combines USDC from multiple chains into a single spendable balance. Earn Kit integrates earn opportunities into your app. Borrow Kit lets users borrow USDC against cirBTC collateral on Arc.
> Use Arc Foundry for contract development. Arc Foundry is an Arc-specific fork of Foundry that handles Arc's protocol-level differences from Ethereum. It provides arc-forge, arc-cast, and arc-anvil. Install it before deploying contracts: https://docs.arc.io/arc/tutorials/install-arc-foundry.md.
> Arc is available on both Testnet and Mainnet. See https://docs.arc.io/arc/references/connect-to-arc.md for RPC endpoints and https://faucet.circle.com for testnet tokens.
> Always check Contract Addresses: https://docs.arc.io/arc/references/contract-addresses.md
> Building beyond Arc? Circle offers skills for the full platform: use-usdc (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md), use-circle-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md), use-developer-controlled-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md), use-user-controlled-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md), use-modular-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md), use-gateway (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md), use-smart-contract-platform (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md). Full Circle developer docs: https://developers.circle.com/llms.txt.
# How-to: Specify a recipient address
> Send swapped tokens to a different address on the same chain
export const TryOnArcStudio = () => {
const [copied, setCopied] = useState(false);
const [prompt, setPrompt] = useState("");
useEffect(() => {
const url = `https://docs.arc.io${window.location.pathname}.md`;
setPrompt(`Read the guide at ${url}, implement it in a new project, then run it and show me how it works.`);
}, []);
const arcStudioUrl = `https://studio.arc.io/app?prompt=${encodeURIComponent(prompt)}`;
const handleArcStudioClick = () => {
try {
if (typeof navigator !== "undefined" && navigator.clipboard && prompt) {
navigator.clipboard.writeText(prompt).then(() => {
setCopied(true);
setTimeout(() => setCopied(false), 4000);
}, () => {});
}
} catch (e) {}
};
return
Try it on Arc Studio
{copied &&
Opening Arc Studio — prompt copied to your clipboard in case you need to
sign in first.
}
;
};
By default, the tokens you receive from a swap arrive at the same address as
your signing wallet. For same-chain swaps, you can specify a different recipient
so the output tokens go to that address instead. Your signing wallet still signs
and funds the swap.
For crosschain swaps, see
[Swap tokens across blockchains](/app-kit/quickstarts/swap-tokens-crosschain).
## Prerequisites
Before you begin, ensure that you've:
* [Installed the App Kit SDK](/app-kit/tutorials/installation)
* [Configured an adapter](/app-kit/tutorials/adapter-setups)
These are required so any example below runs with a valid `kit` and `adapter`.
## Specify a recipient
Set the recipient with the `to` parameter. For a same-chain swap, `to.chain`
defaults to the source chain (`from.chain`), so you only need to set
`to.recipientAddress`.
This example swaps 1.00 USDC for EURC on Arc Testnet and sends the EURC to a
different address than the one that signs the swap:
```typescript TypeScript theme={null}
const result = await kit.swap({
from: { adapter, chain: "Arc_Testnet" },
tokenIn: "USDC",
tokenOut: "EURC",
amountIn: "1.00",
to: {
recipientAddress: "0xRecipientAddress",
},
config: {
apiKey: process.env.CIRCLE_API_KEY as string, // optional — configure for production or high-volume usage
},
});
```
`to.recipientAddress` sets where the output tokens are sent. It's different from
`config.customFee.recipientAddress`, which sets the recipient of a
[custom swap fee](/app-kit/tutorials/swap/collect-swap-fee).