> ## 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.

# How-to: Swap tokens

> Swap one token for another from your agent wallet.

Swap tokens from your agent wallet using `circle wallet swap`. Optionally get a
price quote first to verify the expected output before committing funds.

## Prerequisites

Before you begin, ensure you have:

* Installed [Node.js v20.18.2 or later](https://nodejs.org/).

* Installed Circle CLI:

  ```bash theme={null}
  npm install -g @circle-fin/cli
  ```

* Completed the
  [Agent Wallets quickstart](/agent-stack/agent-wallets/quickstart)
  (authenticates and funds your wallet).

## Steps

<Steps>
  <Step title="Get a quote (optional)">
    Run `circle wallet swap` with `--quote` to see the estimated output without
    executing the swap:

    ```bash theme={null}
    circle wallet swap EURC 10 USDC --chain ARC --quote
    ```

    ```json theme={null}
    {
      "data": {
        "message": "Quote: 10 EURC → ~9.95 USDC (min 0.000001) on ARC",
        "sellToken": "EURC",
        "sellAmount": "10",
        "buyToken": "USDC",
        "chain": "ARC",
        "estimatedOutput": "9.95",
        "stopLimit": "0.000001"
      }
    }
    ```
  </Step>

  <Step title="Swap tokens">
    Run `circle wallet swap` with your wallet address and a `<buyAmount>`
    stop-limit. If the estimated output falls below this value onchain, the swap
    fails instead of settling at an unfavorable rate:

    ```bash theme={null}
    circle wallet swap EURC 10 USDC 9.9 --address 0xYourWalletAddress --chain ARC
    ```

    ```json theme={null}
    {
      "data": {
        "message": "Swap complete: 10 EURC → min 9.9 USDC on ARC",
        "sellToken": "EURC",
        "sellAmount": "10",
        "buyToken": "USDC",
        "buyMin": "9.9",
        "chain": "ARC"
      }
    }
    ```
  </Step>
</Steps>

See the [CLI command reference](/agent-stack/circle-cli/command-reference) for
full syntax and options, including `--slippage-bps` to set maximum slippage.