openapi: 3.1.0 info: title: Circle Web3 Services (W3S) — Developer-Controlled Wallets NFTs Signing API description: 'Circle''s Web3 Services API for developer-controlled programmable wallets, wallet sets, signing, transactions, tokens, and NFTs. This is a best-effort partial spec derived from Circle''s published OpenAPI at https://developers.circle.com/openapi/developer-controlled-wallets.yaml.' version: '2026-05-23' contact: name: Circle Developer Support url: https://developers.circle.com/ license: name: Proprietary servers: - url: https://api.circle.com description: Production security: - BearerAuth: [] tags: - name: Signing paths: /v1/w3s/developer/sign/message: post: tags: - Signing summary: Sign a message operationId: signMessage responses: '200': description: Signature /v1/w3s/developer/sign/typedData: post: tags: - Signing summary: Sign EIP-712 typed data operationId: signTypedData responses: '200': description: Signature /v1/w3s/developer/sign/transaction: post: tags: - Signing summary: Sign a transaction operationId: signTransaction responses: '200': description: Signature /v1/w3s/developer/sign/delegateAction: post: tags: - Signing summary: Sign a delegate action operationId: signDelegateAction responses: '200': description: Signature components: securitySchemes: BearerAuth: type: http scheme: bearer description: Circle API key, formatted as `PREFIX:ID:SECRET`, supplied as Bearer token.