> ## 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. # Liquidity services > Access institutional-grade tools for minting USDC and EURC directly from Circle, executing stablecoin FX trades, and offering stablecoin-backed accounts to your business customers. ## What you can build Circle provides institutional infrastructure for accessing digital currencies, executing stablecoin FX trades, and enabling stablecoin-backed account services. These tools enable banks, exchanges, payment providers, and fintechs to integrate USDC and EURC into their operations at scale. Key capabilities: * **Direct USDC and EURC minting**: Access digital currencies directly from Circle, the sole issuer, with 1:1 redemption guarantees. * **Institutional FX execution**: Execute stablecoin currency swaps with competitive rates from multiple liquidity providers. * **24/7 settlement**: Trade and settle around the clock with sub-second finality on Arc blockchain. * **Stablecoin-backed accounts**: Offer your business customers dedicated accounts with fiat deposits, crypto transfers, and Circle-managed custody. * **Simplified operations**: Reduce reliance on multiple intermediaries and bilateral agreements with unified API access. ## Choose your product These products are designed for institutional customers with different use cases: Mint and redeem USDC and EURC directly from Circle. Manage funds securely and distribute them to crypto wallets globally, 24/7. Institutional-grade stablecoin FX engine built on Arc. Execute USDC and EURC trades with aggregated liquidity and smart contract settlement. Offer stablecoin-backed account capabilities to your business customers with fiat deposits, crypto transfers, and Circle-managed custody. ## Circle Mint Circle Mint is the fastest and most cost-effective way for institutions to access and redeem USDC and EURC. Your Circle Mint account allows you to manage funds securely and distribute them worldwide using a web UI or API integration. **Benefits:** * Fiat funds from your bank account are automatically converted to USDC and EURC * Participating banks offer instant settlement programs * USDC and EURC can always be redeemed 1:1 for US dollars or Euros **Who should use Circle Mint:** * Exchanges and institutional traders * Wallet providers and custodians * Banks and payment service providers * Consumer app companies requiring stablecoin infrastructure Circle Mint is for institutional customers. [Contact Circle](https://www.circle.com/mint-contact) to learn more about accessing the platform. ## StableFX StableFX is an institutional-grade FX engine that combines Request-for-Quote (RFQ) execution with onchain settlement. This permissioned platform is designed for financial institutions including payment service providers, fintechs, crypto OTC desks, and prime brokers. **Key features:** * **Aggregated liquidity**: Access competitive rates from multiple liquidity providers through a single API call * **24/7 settlement**: Trade and settle around the clock with sub-second finality on Arc * **Simplified operations**: Replace multiple bilateral agreements with one integration * **Smart contract escrow**: Both sides of a trade settle simultaneously or not at all **Common use cases:** * Cross-border payment flows with real-time currency conversion * Institutional treasury management and automated rebalancing * Embedded FX liquidity services for platforms * Next-generation remittance solutions with guaranteed settlement Reach out to your [Circle representative](mailto:sales@circle.com) to get an API key for StableFX. ## Digital Asset Accounts Digital Asset Accounts enables distributors such as fintechs, platforms, and marketplaces to offer stablecoin-backed account features to their business end customers. Circle retains custody, compliance, and regulatory oversight under a Direct End-User Custody model. **Key features:** * **Fiat deposits and withdrawals**: Fund accounts through wire transfers with automatic stablecoin minting and redemption * **Crypto transfers**: Send and receive stablecoins to and from external blockchain addresses * **Internal transfers**: Move funds instantly between subaccounts with no blockchain fees * **Custody balances**: Real-time balance visibility with Circle-managed custody **Common use cases:** * Fintech wallets with stablecoin-powered account experiences * Marketplace payouts to sellers and service providers * SMB financial operating systems with multi-currency support * Cross-border B2B payment solutions Reach out to your [Circle representative](mailto:sales@circle.com) to get API access for Digital Asset Accounts. ## Dive deeper * Learn about [Circle Mint core capabilities](/circle-mint/quickstarts/getting-started) including deposits, withdrawals, and transfers. * Follow the [StableFX taker quickstart](/stablefx/quickstarts/fx-trade-taker) to request and execute your first USDC to EURC trade. * Follow the [StableFX maker quickstart](/stablefx/quickstarts/fx-trade-maker) to fulfill trades and provide liquidity. * Follow the [Digital Asset Accounts fiat funding quickstart](/digital-asset-accounts/quickstarts/fund-account-with-wire-deposit) to deposit fiat and verify your stablecoin balance. * Explore [Circle Mint supported chains](/circle-mint/references/supported-chains-and-currencies), [StableFX supported currencies](/stablefx/references/supported-currencies), and [Digital Asset Accounts supported currencies and blockchains](/digital-asset-accounts/references/supported-currencies-and-blockchains).