> ## 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. # Release notes - Digital Asset Accounts - 2026 > 2026 release notes for Digital Asset Accounts ## October 2026 ### API additions Added crypto payments, payment intents, payouts, and address book endpoints to the Digital Asset Accounts API. * [List payments](/api-reference/digital-asset-accounts/all/list-payments) * [Create a payment intent](/api-reference/digital-asset-accounts/all/create-payment-intent) * [Create a crypto payout](/api-reference/digital-asset-accounts/all/create-payout) * [Create an address book recipient](/api-reference/digital-asset-accounts/all/create-address-book-recipient) ### Documentation additions Added new documentation for Digital Asset Accounts in the European Economic Area (EEA) under MiCA, including Strong Customer Authentication (SCA). * [EEA operations under MiCA](/digital-asset-accounts/concepts/eea-and-mica) * [How-to: Onboard EEA customers](/digital-asset-accounts/howtos/onboard-eea-customers) * [EEA API behavior](/digital-asset-accounts/references/eea-api-behavior) * [Compliance obligations](/digital-asset-accounts/references/compliance-obligations) * [How Strong Customer Authentication works](/digital-asset-accounts/concepts/strong-customer-authentication) ## September 2026 ### Documentation additions Added new documentation to support Strong Customer Authentication (SCA), which lets end users approve sensitive operations with a WebAuthn passkey. * [How Strong Customer Authentication works](/digital-asset-accounts/concepts/strong-customer-authentication) * [Implement Strong Customer Authentication](/digital-asset-accounts/howtos/strong-customer-authentication) * [DAA web SDK reference](/sdks/daa/web-sdk) * [Open a passkey registration session](/api-reference/digital-asset-accounts/all/open-passkey-registration) * [Create an SCA challenge](/api-reference/digital-asset-accounts/all/create-sca-challenge) ### Blockchain expansion Added Arc mainnet as a supported blockchain for Digital Asset Accounts. Updated topics: * [Supported currencies and blockchains](/digital-asset-accounts/references/supported-currencies-and-blockchains) ## August 2026 ### Breaking changes * **`riskSignals` now required on money-movement endpoints**: The `riskSignals` object (`ipAddress`, `sessionId`, and `deviceId`) is now a required request field on the following endpoints. Requests that omit it will fail, so update your integration to collect and pass these values. * [Create a transfer](/api-reference/digital-asset-accounts/all/create-account-transfer) * [Create a recipient address](/api-reference/digital-asset-accounts/all/create-recipient-address) * [Create a withdrawal](/api-reference/digital-asset-accounts/all/create-account-withdrawal) * [Create a wire bank account](/api-reference/digital-asset-accounts/all/create-wire-account) ## July 2026 ### New features * **ACH bank account support**: You can now link and manage ACH bank accounts for Digital Asset Accounts, in addition to wire. Use the new endpoints to create an ACH bank account, retrieve its details, and fetch deposit instructions for funding an account via ACH. * [Create an ACH bank account](/api-reference/digital-asset-accounts/all/create-achaccount) * [Get an ACH bank account](/api-reference/digital-asset-accounts/all/get-achaccount) * [Get ACH instructions](/api-reference/digital-asset-accounts/all/get-achaccount-instructions) ## March 2026 Launched Digital Asset Accounts, a product that enables distributors to offer stablecoin-backed account features to their business end customers with Circle-managed custody and compliance. ### Documentation additions Added the following documentation to support the Digital Asset Accounts launch: * [Digital Asset Accounts overview](/digital-asset-accounts) * [Account structure](/digital-asset-accounts/concepts/account-structure) * [Supported currencies and blockchains](/digital-asset-accounts/references/supported-currencies-and-blockchains) * [Sandbox environment](/digital-asset-accounts/references/testing-in-sandbox) * [Wire deposits and withdrawals](/digital-asset-accounts/howtos/wire-deposits-and-withdrawals) * [Deposit Addresses](/digital-asset-accounts/howtos/create-deposit-addresses) * [Crypto Transfers](/digital-asset-accounts/howtos/crypto-transfers) * [Internal Transfers](/digital-asset-accounts/howtos/internal-transfers) * [Set up a webhook endpoint](/api-reference/webhook-endpoints#v2-notifications) * [Direct end-user custody model](/digital-asset-accounts/concepts/custody-model) * [Limits and risk ratings](/digital-asset-accounts/concepts/limits-and-risk-ratings) * [Transaction states](/digital-asset-accounts/references/transaction-states) * [Going to production](/digital-asset-accounts/references/going-to-production)