{"uid":"cap_4USBZakAlJN8E5g6zOauq","slug":"util-beauty-crypto-signature-utility-00c884ca","name":"util.beauty Crypto Signature Utility","description":"Metered web utilities for developers and AI agents: browser screenshot and PDF, crypto, DNS and net tools. Pay per request with x402 (USDC on Base) or prepaid API keys.","url":"https://util.beauty/v1/crypto/signature","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"type":"object","properties":{"body":{"type":"object","description":"JSON request body (see OpenAPI for the utility schema).","additionalProperties":true}}},"output":{"type":"object","properties":{"example":{"type":"object","properties":{"ok":{"type":"boolean"},"utility":{"type":"string"},"requestId":{"type":"string"},"chargedCredits":{"type":"number"}},"additionalProperties":true}}}}},"responseSchema":{"type":"json","example":{"ok":true,"utility":"…","requestId":"req_…","chargedCredits":1}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_X5urg5cOYeZyNiTooCnvV","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Generates or verifies cryptographic signatures via a metered REST endpoint, payable per-request with USDC on Base or prepaid API keys.","exampleAgentPrompt":"Sign this message — 'Hello, world!' — using my private key, and give me back the cryptographic signature I can use to prove ownership.","exampleUseCases":[{"title":"Prove wallet ownership off-chain","prompt":"I need to sign the message 'I authorize this action at 2024-06-01T12:00:00Z' with my private key so I can prove I own this wallet without broadcasting a transaction."},{"title":"Verify a counterparty's signed message","prompt":"Can you check whether this signature is valid? The original message was 'Transfer approved', the claimed public key is 0xABC123, and the signature bytes are 0xDEF456 — I need to know if the signer really holds that key."},{"title":"Generate signature for API webhook auth","prompt":"Sign the string 'webhook-payload-hash-abc123' with my ECDSA private key so I can attach it as an auth header when calling my partner's webhook endpoint."}],"resultDescription":"Returns a JSON object with ok (boolean), a utility identifier string, a unique requestId, the number of charged credits, and the computed signature or verification result in the response body.","failureModes":["Invalid or malformed private key returns an error response with ok: false","Unsupported signature algorithm causes a 400-level error","Insufficient payment balance or invalid x402 payment header causes a 402 Payment Required response","Malformed JSON body causes a 400 Bad Request","Key/message mismatch during verification returns ok: false with a verification failure indicator"],"whenToPreferThis":"Choose this endpoint when you need a quick, pay-per-use cryptographic signing or verification operation without deploying your own crypto infrastructure. Ideal for AI agents or serverless workflows that occasionally need to sign messages or verify signatures, especially in web3 or API-auth contexts, without managing long-lived secrets or heavyweight SDKs.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T12:47:43.148Z","isFirstParty":false}