{"uid":"cap_MK4sKIXuwqnbgSWFEdN-z","slug":"hmac-sha224-hex-digest-api-b461e5bb","name":"HMAC-SHA224 Hex Digest API","description":"Call when an agent needs an HMAC-sha224 of text with a caller-supplied key, encoded as hex. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha224-hex first.","url":"https://agentshelf.syntexa.ch/v1/hmac-sha224-hex?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"key":{"type":"string","examples":["secret"],"maxLength":512,"minLength":1,"description":"HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."},"text":{"type":"string","examples":["hello"],"maxLength":100000,"minLength":1,"description":"Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","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":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_j34E-khcbo9OmU3zWwqUc","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes an HMAC-SHA224 message authentication code for a given text using a caller-supplied key, returning the result as a lowercase hex string.","exampleAgentPrompt":"Compute the HMAC-SHA224 hex digest of the text 'Hello, World!' using the secret key 'mysecretkey123'.","exampleUseCases":[{"title":"Webhook signature verification","prompt":"Generate an HMAC-SHA224 hex signature for the webhook payload '{\"event\":\"payment.completed\",\"amount\":100}' using the secret key 'whsec_abc123XYZ' so I can validate it matches the incoming header."},{"title":"API request signing","prompt":"I need to sign the API request body 'user_id=42&action=transfer&amount=500' with HMAC-SHA224 using the key 'api_signing_key_prod' — give me the hex digest."},{"title":"Data integrity token for file content","prompt":"Create an HMAC-SHA224 hex digest for the text 'report_2024_q4.csv contents here' using the secret 'integrity_token_secret' so I can store it alongside the file and check for tampering later."}],"resultDescription":"Returns a hex-encoded HMAC-SHA224 digest string (56 hex characters) computed over the provided text using the supplied key. The response is a deterministic, fixed-length authentication code that can be used for message integrity verification or API request signing.","failureModes":["Missing or empty key parameter returns a validation error","Missing or empty text parameter returns a validation error","Text exceeding 100,000 characters is rejected","Key exceeding 512 characters is rejected","Payment failure or insufficient USDC balance prevents the call from completing","Network timeout may occur under load"],"whenToPreferThis":"Choose this endpoint when you specifically need HMAC-SHA224 (not SHA-256 or SHA-512) as a keyed hash for message authentication or integrity verification, and when a hex-encoded output is required. Prefer the free sandbox endpoint POST /v1/sandbox/hmac-sha224-hex during development or testing to avoid the $0.01 USDC charge. Use this paid endpoint for production workloads where reliable uptime and SLA matter.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T06:50:09.240Z","isFirstParty":false,"canonicalSlug":"hmac-sha224-hex-digest-api-b461e5bb"}