> ## 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 API behavior > EEA API controls for Digital Asset Accounts integrations, including mTLS, SCA, the platform address book, fail-closed asset scope, and MiCA balance reporting. European Economic Area (EEA) integrations are subject to additional controls under the MiCA authorization of Circle France SAS. To set up EEA accounts, see [Onboard EEA customers](/digital-asset-accounts/howtos/onboard-eea-customers). For conceptual background on the EEA regulatory framework, see [EEA and MiCA](/digital-asset-accounts/concepts/eea-and-mica). ## Authentication An EEA integration authenticates at two independent layers. Implement both: | Layer | Who it authenticates | Mechanism | Applies to | | - | - | - | - | | Platform (transport) | Your platform, as the distributor entity | API key plus mutual TLS (mTLS) on the regional EU host | All of your entity's API traffic, not individual end users | | End user (SCA) | The end user who approves the operation | Strong Customer Authentication (SCA) with a WebAuthn passkey per operation | [Protected operations](/digital-asset-accounts/concepts/strong-customer-authentication#protected-operations) | ### Platform authentication Under MiCA, your entity authenticates to Circle with mTLS in addition to your API key. Circle issues your client certificate from its private certificate authority; you don't purchase a Qualified Website Authentication Certificate (QWAC) or any other third-party certificate. Circle presents a QWAC as its server certificate on the regional EU host, `api-eu.circle.com`, and your client validates it. See [How mTLS authentication works](/circle-mint/mtls-authentication). ### End-user approval with SCA Each money movement or trusted-destination change for an end user booked to Circle's EEA entity requires a passkey approval from that end user. Your platform's API key and mTLS session don't satisfy this requirement on their own: a protected endpoint returns HTTP `428` until the request carries a valid SCA assertion. See [How Strong Customer Authentication works](/digital-asset-accounts/concepts/strong-customer-authentication) and [Implement Strong Customer Authentication](/digital-asset-accounts/howtos/strong-customer-authentication). ### Console sign-in for your team Your own team members who use the [Mint Console](https://app.circle.com/) sign in with Okta Verify (possession factor) and a 4-digit PIN (knowledge factor). This governs your staff's console access, such as creating API keys or changing IP allowlist settings. It's separate from end-user SCA and doesn't apply to API calls. ## Platform address book EEA outbound crypto transfers are subject to Travel Rule obligations and strict beneficiary controls. Register every external beneficiary address as a [recipient address](/api-reference/digital-asset-accounts/all/create-recipient-address) before you initiate a transfer to it. For end users booked to Circle's EEA entity, the request must declare wallet `ownership`, and adding or deleting an address requires an SCA approval. ### Address statuses | Status | Description | | - | - | | `pending_verification` | The end user hasn't yet proven control of the wallet. Transfers aren't permitted. | | `verification_succeeded` | Ownership is verified and Circle is activating the address. | | `active` | The address is eligible for transfers. | | `failed` | Verification failed. Transfers aren't permitted. | | `disabled` | The address was removed or disabled. Transfers aren't permitted. | Transfers to an address that isn't registered, or that isn't `active`, are rejected at the API level. This is fail-closed behavior: there is no silent degradation or fallback. Deposit addresses are not part of the Platform Address Book; the address book governs outbound transfers only. ## Fail-closed asset scope Digital Asset Accounts in the EEA is limited to operations in the scope of MiCA Article 60(4). API requests for out-of-scope operations return an error. The following operations are blocked in the EEA: | Blocked operation | Expected behavior | | - | - | | Swap | Returns an error | | Earn | Returns an error | | Assets other than USDC and EURC | Returns an error | | Locally issued stablecoins | Returns an error | ## No burn fees Digital Asset Accounts does not charge burn fees and does not participate in redeemer of last resort (ROLR) programs for EEA accounts. ## MiCA balance reporting EEA distributors' subaccount balances are included in Circle's ACPR regulatory reporting through the Reserve Management API. Circle files the MiCA balance report with the ACPR on behalf of your program. You do not submit this report directly. ### Endpoint Submit balance data using the following endpoint: ```bash theme={null} POST /v2/reserveManagement/dailyCustodyBalances ``` For the full request schema, response, and error codes, see the [Reserve Management API reference](/api-reference/circle-mint/reserve-management/report-daily-custody-balances). ### Required fields Set `reportType` to `eea`. The following top-level field is also required: | Field | Description | | - | - | | `localBalance` | Token-unit count of EU-client subset balances. EU clients are determined by habitual residence (natural persons) or registered office (legal persons). | The following fields are required in `additionalFields`: | Field | Description | | - | - | | `equivalentEuroLocalBalance` | Euro-equivalent value of the EU-client subset balance, using the European Central Bank (ECB) exchange rate for the reporting date | | `totalBalance` | Total Crypto-Asset Service Provider (CASP) holdings in the base currency | | `equivalentEuroTotalBalance` | Euro-equivalent value of total CASP holdings, using the ECB exchange rate for the reporting date | ### Reporting rules * **FX conversion**: Euro-equivalent values use the ECB rate for the reporting date. * **Frequency**: One submission per day, per currency. USDC and EURC are submitted as separate reports. * **Currency scope**: Only USDC and EURC are in scope for reporting. For the full set of EEA distributor compliance obligations, see [Compliance obligations](/digital-asset-accounts/references/compliance-obligations).