{"uid":"cap_zUwnkapUM5wZkbX8yIYiG","slug":"hmac-sha3-384-base64-signing-03d2495e","name":"HMAC-SHA3-384 Base64 Signing","description":"Call when an agent needs an HMAC-sha3-384 of text with a caller-supplied key, encoded as base64. Exact $0.004 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha3-384-base64 first.","url":"https://agentshelf.syntexa.ch/v1/hmac-sha3-384-base64?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":"0.004","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":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_ybJtutCiUTnH2FC6hM-zQ","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.004","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes an HMAC-SHA3-384 message authentication code for a given text and key, returning the result encoded as base64","exampleAgentPrompt":"Compute the HMAC-SHA3-384 of the message 'Hello, world!' using the secret key 'mysecretkey123' and give me the result as a base64 string.","exampleUseCases":[{"title":"Webhook payload authentication","prompt":"I need to sign this webhook payload 'user_id=42&event=signup' with the secret key 'wh_secret_abc' using HMAC-SHA3-384 and get back the base64 result so I can include it in my webhook signature header."},{"title":"API request integrity check","prompt":"Can you generate an HMAC-SHA3-384 base64 tag for the string '{\"order\":\"12345\",\"amount\":99.99}' using my signing key 'order-signing-key-xyz'? I need it to verify the integrity of my API request body."},{"title":"Secure token generation for session","prompt":"Generate an HMAC-SHA3-384 in base64 for the text 'session:user:9876:expires:1720000000' using the key 'session_master_key_prod' — I want to use it as a tamper-proof session token."}],"resultDescription":"Returns a base64-encoded HMAC-SHA3-384 digest string computed from the provided text and key. The output is the raw MAC encoded as standard base64, suitable for use in authentication headers, signature verification, or integrity checks.","failureModes":["Key or text exceeds length limits (key >512 chars, text >100000 chars) — validation error","Missing required fields (key or text) — schema validation error","Payment failure or insufficient USDC balance — 402 Payment Required","Network timeout or service unavailability — 5xx error"],"whenToPreferThis":"Choose this endpoint when you specifically need HMAC-SHA3-384 (not SHA-256 or SHA-512 variants) with base64 output encoding. Prefer this over a general hashing service when SHA3-384 algorithm strength is required for compliance or security policy. Use the free sandbox endpoint (/v1/sandbox/hmac-sha3-384-base64) first during development; switch to this paid endpoint for production workloads requiring guaranteed availability.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T06:50:18.031Z","isFirstParty":false,"canonicalSlug":"hmac-sha3-384-base64-signing-03d2495e"}