> ## 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. # Derive a wallet > Derives an EOA (Externally Owned Account) or SCA (Smart Contract Account) wallet using the address of the specified wallet and blockchain. If the target wallet already exists, its metadata will be updated with the provided metadata. This operation is only supported for EVM-based blockchains. ## OpenAPI ````yaml openapi/developer-controlled-wallets.yaml put /v1/w3s/developer/wallets/{id}/blockchains/{blockchain} openapi: 3.0.3 info: version: '1.0' title: Developer-Controlled Wallets description: Developer-Controlled Wallets API documentation. servers: - url: https://api.circle.com security: - BearerAuth: [] tags: - name: Wallet Sets - name: Wallets - name: Signing - name: Transactions - name: Token Lookup paths: /v1/w3s/developer/wallets/{id}/blockchains/{blockchain}: put: tags: - Wallets summary: Derive a wallet description: >- Derives an EOA (Externally Owned Account) or SCA (Smart Contract Account) wallet using the address of the specified wallet and blockchain. If the target wallet already exists, its metadata will be updated with the provided metadata. This operation is only supported for EVM-based blockchains. operationId: deriveWallet parameters: - $ref: '#/components/parameters/Id' - $ref: '#/components/parameters/XRequestId' - description: The unique identifier of the blockchains. name: blockchain in: path required: true schema: $ref: '#/components/schemas/EvmBlockchain' requestBody: $ref: '#/components/requestBodies/DeriveWallet' responses: '200': description: Successfully updated the metadata for an existing wallet. content: application/json: schema: $ref: '#/components/schemas/WalletResponse' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' '201': description: The derived wallet was successfully created. content: application/json: schema: $ref: '#/components/schemas/WalletResponse' headers: X-Request-Id: $ref: '#/components/headers/XRequestId' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/NotAuthorized' '404': $ref: '#/components/responses/NotFound' security: - BearerAuth: [] components: parameters: Id: name: id description: The universally unique identifier of the resource. in: path required: true schema: type: string format: uuid example: b3d9d2d5-4c12-4946-a09d-953e82fae2b0 XRequestId: name: X-Request-Id in: header description: > Developer-provided identifier for this request, used for tracing requests in Wallets API logs and the Developer Console, and when communicating with Circle Support. **Must be a UUID to appear in logs.** Non-UUID values are accepted by the API but are ignored by logging and tracing systems. schema: $ref: '#/components/schemas/XRequestId' schemas: EvmBlockchain: type: string description: >- The blockchain network that the resource is to be created on or is currently on. enum: - ETH - ETH-SEPOLIA - AVAX - AVAX-FUJI - MATIC - MATIC-AMOY - ARB - ARB-SEPOLIA - UNI - UNI-SEPOLIA - BASE - BASE-SEPOLIA - OP - OP-SEPOLIA - EVM - EVM-TESTNET - ARC - ARC-TESTNET - MONAD - MONAD-TESTNET example: MATIC-AMOY WalletResponse: title: WalletResponse type: object required: - data properties: data: type: object required: - wallet properties: wallet: oneOf: - $ref: '#/components/schemas/EOAWallet' - $ref: '#/components/schemas/SCAWallet' discriminator: propertyName: accountType XRequestId: type: string format: uuid description: >- A unique identifier, which can be helpful for identifying a request when communicating with Circle support. example: 2adba88e-9d63-44bc-b975-9b6ae3440dde WalletMetadata: type: object properties: name: $ref: '#/components/schemas/Name' refId: $ref: '#/components/schemas/ReferenceId' EOAWallet: title: EOAWallet allOf: - $ref: '#/components/schemas/Wallet' - type: object required: - accountType properties: accountType: type: string description: > An account can be a Smart Contract Account (SCA) or an Externally Owned Account (EOA). To learn more, see the [account types guide](https://developers.circle.com/wallets/account-types). If an account type is not specified during the creation of a wallet, it defaults to `EOA` (Externally Owned Account). Note that Solana and Aptos don't support Smart Contract Account (SCA). enum: - EOA SCAWallet: title: SCAWallet allOf: - $ref: '#/components/schemas/Wallet' - type: object required: - accountType - scaCore properties: accountType: type: string description: > An account can be a Smart Contract Account (SCA) or an Externally Owned Account (EOA). To learn more, see the [account types guide](https://developers.circle.com/wallets/account-types). If an account type is not specified during the creation of a wallet, it defaults to `EOA` (Externally Owned Account). Note that Solana and Aptos don't support Smart Contract Account (SCA). enum: - SCA scaCore: $ref: '#/components/schemas/ScaCore' Name: type: string description: Name or description associated with the wallet or walletSet. ReferenceId: type: string description: >- Optional user-defined reference identifier for the wallet. Not used by Circle for wallet functionality. Used for internal tracking or associating wallets with entities in your own systems (for example, a customer or account ID). example: customer_12345 Wallet: type: object required: - id - state - walletSetId - custodyType - address - blockchain - createDate - updateDate properties: id: $ref: '#/components/schemas/Id' address: $ref: '#/components/schemas/Address' blockchain: $ref: '#/components/schemas/Blockchain' createDate: $ref: '#/components/schemas/CreateDate' updateDate: $ref: '#/components/schemas/UpdateDate' custodyType: $ref: '#/components/schemas/CustodyType' name: $ref: '#/components/schemas/Name' refId: $ref: '#/components/schemas/ReferenceId' state: $ref: '#/components/schemas/WalletState' userId: $ref: '#/components/schemas/ExternalUserId' walletSetId: $ref: '#/components/schemas/Id' initialPublicKey: $ref: '#/components/schemas/InitialPublicKey' ScaCore: type: string description: >- SCAs have different versions, each with unique functionality. `SCACore` displays the version of the SCA being created. For a list of supported versions, refer to the developer documentation. enum: - circle_4337_v1 - circle_6900_singleowner_v1 - circle_6900_singleowner_v2 - circle_6900_singleowner_v3 - circle_6900_singleowner_v4 example: circle_6900_singleowner_v4 Id: type: string format: uuid description: System-generated unique identifier of the resource. example: c4d1da72-111e-4d52-bdbf-2e74a2d803d5 Address: title: Address description: > Blockchain generated unique identifier, associated with wallet (account), smart contract or other blockchain objects. type: string example: '0xca9142d0b9804ef5e239d3bc1c7aa0d1c74e7350' Blockchain: type: string description: >- The blockchain network that the resource is to be created on or is currently on. enum: - ETH - ETH-SEPOLIA - AVAX - AVAX-FUJI - MATIC - MATIC-AMOY - SOL - SOL-DEVNET - ARB - ARB-SEPOLIA - NEAR - NEAR-TESTNET - EVM - EVM-TESTNET - UNI - UNI-SEPOLIA - BASE - BASE-SEPOLIA - OP - OP-SEPOLIA - APTOS - APTOS-TESTNET - ARC - ARC-TESTNET - MONAD - MONAD-TESTNET example: MATIC-AMOY CreateDate: type: string format: date-time description: Date and time the resource was created, in ISO-8601 UTC format. example: '2023-01-01T12:04:05Z' UpdateDate: type: string format: date-time description: Date and time the resource was last updated, in ISO-8601 UTC format. example: '2023-01-01T12:04:05Z' CustodyType: type: string description: > Describes who controls the digital assets in a wallet: either the end-user or the developer. enum: - DEVELOPER - ENDUSER WalletState: type: string description: This enum describes the current state of the wallet. enum: - LIVE - FROZEN example: LIVE ExternalUserId: type: string description: Unique system generated identifier for the user. example: ext_user_id_1 maxLength: 50 minLength: 5 InitialPublicKey: type: string description: >- For NEAR blockchains only, the originally assigned public key of a wallet at the time of its creation. example: 3eQoJ3ex6uWX3R8F1THF6Y6oBQwPYpF1X9HBM1gjqw7w requestBodies: DeriveWallet: content: application/json: schema: type: object properties: metadata: $ref: '#/components/schemas/WalletMetadata' description: Defines the request payload schema for deriving a new wallet. required: false headers: XRequestId: description: > Developer-provided header parameter or Circle-generated universally unique identifier (UUID v4). Useful for identifying a specific request when communicating with Circle Support. schema: $ref: '#/components/schemas/XRequestId' responses: BadRequest: content: application/json: schema: type: object title: BadRequestResponse required: - code - message properties: code: type: integer description: Code that corresponds to the error. message: type: string description: Message that describes the error. example: code: 400 message: Bad request. description: Request cannot be processed due to a client error. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' NotAuthorized: content: application/json: schema: type: object title: NotAuthorizedResponse required: - code - message properties: code: type: integer description: Code that corresponds to the error. message: type: string description: Message that describes the error. example: code: 401 message: Malformed authorization. description: >- Request has not been applied because it lacks valid authentication credentials. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' NotFound: content: application/json: schema: type: object title: NotFoundResponse required: - code - message properties: code: type: integer description: Code that corresponds to the error. message: type: string description: Message that describes the error. example: code: 404 message: Not found. description: Specified resource was not found. headers: X-Request-Id: $ref: '#/components/headers/XRequestId' securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: PREFIX:ID:SECRET description: >- Circle's API Keys are formatted in the following structure "PREFIX:ID:SECRET". All three parts are required to make a successful request. ````