{"uid":"cap_EtmzgJWh_3F7y0nWXFKzw","slug":"agentresolver-hmac-sha256-signing-51aa5037","name":"AgentResolver HMAC-SHA256 Signing","description":"Verify an x402 endpoint before paying: live payTo, USDC quote, network, asset, resource binding, TLS and endpoint safety for $0.001 on Base or Solana.","url":"https://agentresolver.vercel.app/api/hmac-sha256","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"input":{"type":"string","maxLength":131072},"secret":{"type":"string","maxLength":4096,"minLength":1}}},"responseSchema":{"type":"json","example":{}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","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":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_vFesgxl9C1MPt402YVuWY","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes an HMAC-SHA256 message authentication code for a given input string using a secret key","exampleAgentPrompt":"Compute an HMAC-SHA256 signature for the message 'order-id=12345&amount=99.99' using the secret key 'my-webhook-secret'.","exampleUseCases":[{"title":"Webhook payload signature verification","prompt":"Sign the string 'user_id=42&event=purchase&timestamp=1700000000' with my secret key 'sk_prod_abc123' using HMAC-SHA256 so I can compare it against the signature header from the incoming webhook."},{"title":"API request authentication token","prompt":"I need to create an HMAC-SHA256 signature for the request body 'GET /api/orders/99' using the secret 'api-secret-xyz' to include in the Authorization header."},{"title":"Data integrity check for stored records","prompt":"Generate an HMAC-SHA256 digest for the string 'invoice:8821,total:540.00,currency:USD' with the secret 'integrity-key-2024' so I can store it alongside the record and detect tampering later."}],"resultDescription":"Returns a JSON object containing the HMAC-SHA256 result string (typically hex-encoded), the encoding format used, the operation name ('hmac-sha256'), and the byte count of the input string.","failureModes":["Missing required field 'input' or 'secret' returns a 400 or validation error","Empty string inputs may produce unexpected or zero-length results","Invalid JSON body causes a parse error","Payment not provided or insufficient results in a 402 Payment Required response"],"whenToPreferThis":"Use this endpoint when you need a simple, pay-per-use HMAC-SHA256 computation without setting up a cryptographic library locally, or when running in an environment where native crypto is unavailable. It is ideal for lightweight agent workflows that occasionally need to sign payloads or verify data integrity without bundling crypto dependencies.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-18T12:43:01.769Z","isFirstParty":false}