> ## 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. # EEA operations under MiCA > How Digital Asset Accounts operates in the EEA under Circle France SAS's MiCA authorization, including booking patterns and asset segregation. Digital Asset Accounts in the European Economic Area (EEA) is operated by Circle France SAS, which holds transitional authorization from the [AMF](https://www.amf-france.org/en) (France's financial markets regulator) under the [Markets in Crypto-Assets Regulation (MiCA)](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32023R1114) Article 60(4). This authorization covers custody and transfer of USDC and EURC for business end users across the EEA. Distributors serving the EEA interact with a different booking layer, additional authentication requirements, and stricter asset controls compared to the global model. ## Circle France SAS and MiCA authorization Circle France SAS contracts with EEA-resident end users and is responsible for MiCA compliance in the region. The AMF granted Circle France SAS transitional authorization under MiCA Article 60(4) on April 20, 2026, covering the custody and transfer of USDC and EURC across the EEA. MiCA Article 60(4) is a transitional authorization; it does not confer full Crypto-Asset Service Provider (CASP) authorization. Retail and consumer custody services require full CASP authorization and are outside the current scope of Digital Asset Accounts in the EEA. ## Booking patterns Which Circle entity books an end user's account depends on the distributor's principal place of business and incorporation. Two booking patterns are supported: | Partner entity | End-user entity | Notes | | - | - | - | | Circle France SAS (EEA-resident distributor) | Circle France SAS | Distributor and end users are both booked to Circle France SAS. Full MiCA controls apply. | | Circle LLC (non-EEA distributor) | Circle France SAS | Distributor stays LLC-booked. EEA end users are automatically booked to Circle France SAS; MiCA controls apply at the subaccount level. No re-contracting required. | Cross-entity routing is handled automatically based on end-user residency. Distributors do not manage this directly. For more information, see [Onboard EEA customers](/digital-asset-accounts/howtos/onboard-eea-customers). ## Onchain asset segregation MiCA requires that customer assets be physically segregated onchain rather than pooled in omnibus wallets. Unlike the United States model, where the [Direct End-User Custody model](/digital-asset-accounts/concepts/custody-model) uses omnibus wallet structures and tracks individual balances at the record level, EEA subaccount balances are held in dedicated onchain reserve addresses operated by Circle Mint SAS. Distributors do not configure or manage asset segregation; Circle handles this automatically. ## Platform address book In the EEA, all external beneficiary addresses must be pre-registered in the Platform Address Book before an outbound transfer can be initiated; deposit addresses are excluded. Addresses progress from `PENDING` to `VERIFIED`, or may be permanently `BLOCKED`. For the full address registration workflow and fail-closed behavior, see [EEA API behavior](/digital-asset-accounts/references/eea-api-behavior). Inbound crypto deposits may enter a `held` state pending Travel Rule evaluation; see [Transaction states](/digital-asset-accounts/references/transaction-states). ## Strong customer authentication Strong Customer Authentication (SCA) is required for sensitive actions in the EEA. Two authentication mechanisms apply depending on the context: | Action | Authentication method | | - | - | | Sensitive actions in the UI (Circle Mint shell and Management Console) | Okta Verify (possession factor) + 4-digit PIN (knowledge factor) | | Programmatic money movement through the API | mTLS with a Qualified Website Authentication Certificate (QWAC) | A bearer token alone is insufficient for EEA programmatic money movement. The QWAC is a regulated digital certificate that authenticates the API client as a known legal entity. For the full SCA flow, complete list of SCA-governed actions, and EEA distributor compliance obligations, see [EEA API behavior](/digital-asset-accounts/references/eea-api-behavior) and [Compliance obligations](/digital-asset-accounts/references/compliance-obligations). ## Asset scope Digital Asset Accounts in the EEA supports USDC and EURC only. Swap, earn, additional assets, and locally issued stablecoins are not available in the EEA and are fail-closed at the API level; requests for out-of-scope assets or operations return an error rather than a degraded result. For the full list of supported currencies and blockchains, see [Supported currencies and blockchains](/digital-asset-accounts/references/supported-currencies-and-blockchains).