> ## 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.

# P2P Payments

> Build instant, low-cost peer-to-peer payment flows with stablecoin-native transfers and deterministic finality on Arc.

Build direct, peer-to-peer payment flows using stablecoins on Arc. P2P payments
let users send value directly to each other without an intermediary, settled
onchain in under a second. From [simple transfers](/app-kit/send) to full
checkout experiences with [crosschain bridging](/app-kit/bridge) using App Kits,
Arc provides the infrastructure for fast, low-cost,
[compliant](/arc/tools/compliance-vendors) payments.

For merchant-facing checkout flows, see [eCommerce Checkout](/build/ecommerce).
For cross-currency swaps between stablecoins, see
[Stablecoin FX](/build/stablecoin-fx).

## Sample apps

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

<Columns cols={3}>
  <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 multichain wallet" icon="wallet" href="https://github.com/circlefin/arc-multichain-wallet">
    Unified USDC balance and crosschain transfers using Circle Gateway, Next.js,
    and Supabase.
  </Card>

  <Card title="Arc fintech" icon="building-columns" href="https://github.com/circlefin/arc-fintech">
    Multichain treasury system with crosschain capital movement using Circle
    Developer-Controlled Wallets, Gateway, and Bridge Kit.
  </Card>

  <Card title="Arc nanopayments" icon="bolt" href="https://github.com/circlefin/arc-nanopayments">
    Autonomous AI agent pays for premium API endpoints in USDC fractions using
    Circle Nanopayments and the x402 protocol. Sub-cent pricing relies on
    [batched
    settlement](https://developers.circle.com/gateway/nanopayments/concepts/batched-settlement),
    not per-transaction settlement.
  </Card>
</Columns>

## Quickstarts

Get up and running with payment 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="Bridge tokens across blockchains" icon="bridge" href="/app-kit/quickstarts/bridge-tokens-across-blockchains">
    **Beginner**. Move USDC across blockchains using [App
    Kits](/app-kit/bridge).
  </Card>

  <Card title="Unified Balance deposit and spend" icon="layer-group" href="/app-kit/quickstarts/unified-balance-deposit-and-spend">
    **Intermediate**. Aggregate USDC across blockchains into a single spendable
    balance with [Unified Balance](/app-kit/unified-balance), which consolidates
    multichain USDC into one virtual balance.
  </Card>
</Columns>

## Why Arc for payments

Arc is purpose-built for stablecoin finance. These capabilities directly support
payment applications.

<AccordionGroup>
  <Accordion title="Sub-second finality">
    [Deterministic finality](/arc/concepts/deterministic-finality)—the guarantee
    that a confirmed transaction cannot be reversed or reorganized—means
    payments confirm in under a second, giving senders and recipients immediate
    certainty.
  </Accordion>

  <Accordion title="Near-zero gas fees">
    USDC-denominated gas at stable, predictable prices keeps transaction costs
    minimal. See [gas and fees](/arc/references/gas-and-fees) for current rates.
  </Accordion>

  <Accordion title="Native compliance hooks">
    Built-in integration points for transaction monitoring and wallet screening
    from providers like [Elliptic and TRM Labs](/arc/tools/compliance-vendors).
  </Accordion>

  <Accordion title="Multi-stablecoin support">
    Native support for USDC and EURC. See [contract
    addresses](/arc/references/contract-addresses) for token details, and use
    the [Swap](/app-kit/swap) capability to exchange between currencies.
  </Accordion>

  <Accordion title="Deterministic ordering">
    Transaction ordering guarantees prevent front-running and ensure payments
    settle in the order they are submitted. Learn more about Arc's [consensus
    layer](/arc/concepts/consensus-layer).
  </Accordion>

  <Accordion title="Standard EVM tooling">
    Full [EVM compatibility](/arc/references/evm-differences) means your
    existing Solidity, Hardhat, and Foundry workflows work unchanged. [Deploy on
    Arc](/arc/tutorials/deploy-on-arc) to get started.
  </Accordion>
</AccordionGroup>