> ## 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. # List passkeys > Returns all passkeys registered for an end user, and whether Circle requires SCA for that end user (`sca.required`). ## OpenAPI ````yaml openapi/accounts.yaml get /v1/accounts/passkeys openapi: 3.1.0 info: version: 1.0.0 title: Accounts (Stablecoin) API description: > Circle's Accounts API provides endpoints for managing stablecoin accounts -- including transfers, withdrawals, deposits, wire and ACH bank accounts, and blockchain addresses. An **Account** is a general representation of a ledger or custody object that holds balances. It can be a business account, a stablecoin account ledger for an end user, an extra sub-ledger, or any future custody solution. license: name: Circle License url: https://circle.com/terms servers: - url: https://api-sandbox.circle.com - url: https://api.circle.com security: [] tags: - name: Accounts description: Manage accounts. - name: Account Groups description: Manage custody account groups and their memberships. - name: Limits description: View effective account limits and current usage. - name: Transfers description: > Move funds between accounts or out to a verified blockchain address, and track inbound and outbound onchain transfers. - name: Transactions description: | Get a unified, customer-friendly view of account transaction activity. - name: Wires description: Manage account bank accounts for wire transfers. - name: Deposits description: Get information on account bank deposits. - name: Withdrawals description: Manage account bank withdrawals (fiat offramp). - name: ACH description: Manage account bank accounts for ACH transfers. - name: Deposit Addresses description: Manage account deposit addresses. - name: Recipient Addresses description: Manage account recipient addresses used for transfers. - name: Passkeys description: > Manage WebAuthn passkeys and Strong Customer Authentication (SCA) challenges for end users. - name: Crypto Payments description: > Get crypto payments and crypto refunds received through payment intents. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payments. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Crypto Payment Intents description: > Create, expire, refund, and track payment intents for receiving crypto payments. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payments. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Crypto Payouts description: > Create and track crypto payouts to recipient addresses. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payouts. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: Crypto Address Book description: > Manage address book recipients used as crypto payout destinations. Available for Digital Asset Accounts only on custody accounts (`purpose: custody`), and only for third-party payouts. Not supported when the distributor or the end user is under the Circle FR (`CIRCLE_FR`) or Circle SG (`CIRCLE_SG`) legal entity. - name: FX Trades description: | Quote and execute USDC <> EURC swaps for end users' accounts. - name: FX Settlements description: Get settlements of FX trades. - name: Webhook Subscriptions description: Manage subscriptions to Digital Asset Accounts webhook notifications. - name: Webhooks description: | Webhook event payloads Circle sends to a subscribed endpoint. paths: /v1/accounts/passkeys: get: tags: - Passkeys summary: List passkeys description: > Returns all passkeys registered for an end user, and whether Circle requires SCA for that end user (`sca.required`). operationId: listPasskeys parameters: - name: clientEntityId in: query required: true description: > Identifier of the end user whose passkeys to list. Use the `clientEntityId` returned when you create a client with [Create a partner client](https://developers.circle.com/api-reference/end-user-onboarding/create-partner-client) (`POST /v1/partner/clients`). schema: type: string format: uuid example: a3f1b2c4-d5e6-7890-abcd-ef1234567890 responses: '200': description: Successfully retrieved a list of passkeys. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/ListPasskeysResponse' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' '500': $ref: '#/components/responses/InternalServerError' security: - bearerAuth: [] components: headers: XRequestId: description: > Circle-generated universally unique identifier (UUID v4). Useful for identifying a specific request when communicating with Circle Support. schema: $ref: '#/components/schemas/XRequestId' schemas: ListPasskeysResponse: type: object properties: data: type: object properties: sca: $ref: '#/components/schemas/ScaRequirement' passkeys: type: array description: > All passkeys registered for the end user, including revoked ones (with `revokedDate` set). items: $ref: '#/components/schemas/Passkey' required: - sca - passkeys XRequestId: type: string format: uuid example: 2adba88e-9d63-44bc-b975-9b6ae3440dde ScaRequirement: type: - object - 'null' description: > Whether Circle requires Strong Customer Authentication (SCA) for this end user. Use it to decide whether to prompt passkey enrollment and whether to open a challenge before a protected operation. It is a hint: the protected endpoint is still the enforcement point, and returns HTTP 428 when SCA is required and no SCA headers were sent. `null` means Circle could not determine whether SCA is required right now; treat it as unknown and handle a 428 if one is returned. properties: required: type: boolean description: > `true` when protected operations acting on this end user's behalf require SCA. First-party requests that carry no end user (adding or removing a first-party recipient address, first-party wire-account creation) never require SCA. `false` means Circle does not require SCA; it does not mean SCA is disallowed. example: true required: - required Passkey: type: object properties: passkeyId: type: string format: uuid description: Unique identifier for the passkey. example: a1b2c3d4-e5f6-7890-ab12-cdef34567890 credentialId: type: string description: | The WebAuthn credential ID, base64url-encoded. example: dGhpcyBpcyBhIGJhc2U2NHVybCBleGFtcGxl createDate: type: string format: date-time description: When the passkey was registered. example: '2026-09-24T12:00:00Z' revokedDate: type: - string - 'null' format: date-time description: When the passkey was revoked, if applicable. example: '2026-09-24T13:00:00Z' updateDate: type: string format: date-time description: When the passkey record was last updated. example: '2026-09-24T12:01:00Z' algorithm: type: integer description: > COSE algorithm identifier for the credential's key pair. `-7` is ES256 (P-256), `-257` is RS256. example: -7 aaguid: type: string description: > Authenticator AAGUID in hyphenated UUID format, identifying the authenticator model. Self-asserted; not validated. example: adce0002-35bc-c60a-648b-0b25f1f05503 attestationFormat: type: string description: > Attestation format as received from the browser (e.g. `"packed"`, `"none"`). Stored verbatim; presence is not evidence of verified provenance. example: packed transports: type: array items: type: string description: > Transport hints reported by the browser at registration. Fed into `allowCredentials` on future ceremonies to guide authenticator selection. example: - internal - hybrid backupEligible: type: boolean description: > Self-asserted: whether this credential can sync across devices (e.g. synced passkeys). example: true backupState: type: boolean description: | Self-asserted: whether this credential is currently backed up. example: true signCount: type: integer format: int64 description: > Signature counter reported by the authenticator. Many synced passkeys always report `0` — this alone is not a red flag. example: 0 rpId: type: string description: > The WebAuthn relying-party ID this credential was registered under. Recorded per credential to make a future RP-ID migration detectable. example: circle.com paymentEligible: type: boolean description: > Whether `spcCapable` was requested at enrollment. Records what was **requested**, not a verified outcome — `true` means SPC was requested, not that the authenticator honored it. example: false required: - passkeyId - credentialId - createDate Error: type: object required: - code - message properties: code: type: integer description: > Circle internal status code from the platform `CoreStatusCode` enum (and its domain-specific extensions). **This is not the HTTP status code** — `-1` is the catch-all unknown error, `1`/`2` indicate API parameter problems, `3` is forbidden, `4` is unauthorized, and larger values identify domain-specific failures. Consumers should rely on the HTTP status line for transport-level error class and on this field for the specific Circle error case. example: 2 message: type: string description: >- Internal error message; suitable for logging but not for end-user display. example: API parameter invalid. externalMessage: type: string description: > End-user-displayable error message. Present when the server has generated a customer-facing variant for this error; omitted otherwise. example: The provided amount exceeds the maximum allowed. errors: type: array description: Additional request-field validation errors, when available. items: $ref: '#/components/schemas/ErrorDetail' ErrorDetail: type: object required: - error - message properties: error: type: string description: Machine-readable error identifier. example: invalid_value location: type: string description: Query parameter or request field that caused the error. example: assetType message: type: string description: Human-readable description of the specific error. example: The operation and assetType combination is invalid. responses: BadRequest: description: The request cannot be processed due to a client error. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: 2 message: API parameter invalid. NotAuthorized: description: >- The request has not been applied because it lacks valid authentication credentials. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: 4 message: Unauthorized. InternalServerError: description: >- The server encountered an unexpected condition that prevented it from fulfilling the request. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' content: application/json: schema: $ref: '#/components/schemas/Error' example: code: -1 message: 'Something went wrong. errId: 1f0b0c455e40f753f07b4f0ae6abd4b4' securitySchemes: bearerAuth: type: http scheme: bearer ````