> ## 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.

# eCommerce Checkout

> Accept stablecoin payments in your online store with fast settlement, low fees, and built-in compliance on Arc.

Add stablecoin checkout to your eCommerce application. Arc gives you
[instant settlement](/arc/concepts/deterministic-finality), programmable escrow,
and native [compliance hooks](/arc/tools/compliance-vendors) so you can accept
USDC and EURC payments with confidence.

For peer-to-peer transfers, see [P2P Payments](/build/payments). For
multi-currency conversion at checkout, see
[Stablecoin FX](/build/stablecoin-fx). For agent-initiated purchases, see
[Agentic Economy](/build/agentic-economy).

## Sample apps

Production-ready examples on GitHub you can fork and customize.

<Columns cols={2}>
  <Card title="Arc commerce" icon="credit-card" href="https://github.com/circlefin/arc-commerce">
    Accept USDC payments for in-app purchases using Circle Developer Controlled
    Wallets, Next.js, and Supabase.
  </Card>

  <Card title="Arc escrow" icon="handshake" href="https://github.com/circlefin/arc-escrow">
    Conditional USDC settlement and refund logic for escrow-based checkout flows
    using Circle Wallets, Refund Protocol, and Contract Platform.
  </Card>
</Columns>

## Quickstarts

Get up and running with checkout flows in minutes.

<Columns cols={2}>
  <Card title="Send tokens" icon="paper-plane" href="/app-kit/quickstarts/send-tokens-same-chain">
    **Beginner**. Transfer stablecoins between wallets using [App
    Kit](/app-kit/send).
  </Card>

  <Card title="Deploy contracts" icon="rocket" href="/arc/tutorials/deploy-contracts">
    **Beginner**. Deploy payment-related smart contracts (ERC-20 tokens, NFT
    receipts) on Arc testnet.
  </Card>

  <Card title="Bridge tokens across blockchains" icon="bridge" href="/app-kit/quickstarts/bridge-tokens-across-blockchains">
    **Beginner**. Accept payments from other chains by [bridging
    USDC](/app-kit/bridge) using App Kits.
  </Card>

  <Card title="Monitor contract events" icon="bell" href="/arc/tutorials/monitor-contract-events">
    **Intermediate**. Set up webhooks and event monitors for onchain activity
    such as payment confirmations.
  </Card>
</Columns>

## Why Arc for eCommerce

Arc is purpose-built for stablecoin finance, which simplifies building eCommerce
applications.

<AccordionGroup>
  <Accordion title="Instant settlement">
    [Sub-second deterministic
    finality](/arc/concepts/deterministic-finality)—the guarantee that a
    confirmed transaction cannot be reversed—means no chargebacks and immediate
    payment confirmation for both merchants and customers.
  </Accordion>

  <Accordion title="Stablecoin-native gas">
    Customers and merchants transact in USDC, not volatile gas tokens. Any
    transaction-submitting component (relayer, checkout backend, or escrow
    contract) must hold USDC for gas. See [gas and
    fees](/arc/references/gas-and-fees) for details on Arc's stable fee model.
  </Accordion>

  <Accordion title="Compliance-ready">
    Native hooks for KYC/AML screening from [Elliptic and TRM
    Labs](/arc/tools/compliance-vendors) let you meet regulatory requirements
    without building custom infrastructure.
  </Accordion>

  <Accordion title="Multichain reach">
    Accept payments from any chain [supported by App
    Kit](/app-kit/references/supported-blockchains) via
    [bridging](/app-kit/bridge), so customers can pay from the chain they
    already use.
  </Accordion>

  <Accordion title="Programmable escrow">
    Smart contracts enable milestone-based payment release, refund protocols,
    and conditional settlement logic for marketplace and SaaS checkout flows.
    See the [Arc escrow](https://github.com/circlefin/arc-escrow) sample app for
    a working example.
  </Accordion>

  <Accordion title="Standard EVM tooling">
    Build with Solidity, ethers.js, or viem. Your existing web3 development
    workflows work unchanged on Arc—see [EVM
    compatibility](/arc/references/evm-differences) for details. [Deploy on
    Arc](/arc/tutorials/deploy-on-arc) to get started.
  </Accordion>
</AccordionGroup>