{"uid":"cap_DH7h4DKH_y7-zYtcJcx_7","slug":"hmac-sha384-base64-signer-73d08234","name":"HMAC-SHA384 Base64 Signer","description":"Call when an agent needs an HMAC-sha384 of text with a caller-supplied key, encoded as base64. Exact $0.009 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha384-base64 first.","url":"https://agentshelf.syntexa.ch/v1/hmac-sha384-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":"0.009","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":"$0.009/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.009","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.009","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_pSGA2qWr1_pDaXgat0iun","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.009","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes an HMAC-SHA384 signature of input text using a caller-supplied key and returns it encoded as Base64.","exampleAgentPrompt":"Can you compute the HMAC-SHA384 of the text 'invoice:12345:amount:99.00' using the secret key 'my-super-secret-key-42' and give me the result as Base64?","exampleUseCases":[{"title":"Signing webhook payloads securely","prompt":"I need to sign the webhook body '{\"event\":\"order.created\",\"id\":\"ord_789\"}' with the secret key 'whsec_abc123XYZ' using HMAC-SHA384 and get the Base64 digest so I can include it in the webhook signature header."},{"title":"Authenticating API request integrity","prompt":"Before sending this API request body 'user_id=42&action=transfer&amount=500' to our payment service, sign it with the key 'api-signing-key-prod-2024' using HMAC-SHA384 Base64 so the server can verify it wasn't tampered with."},{"title":"Generating checksum for file content","prompt":"Take the text content of this config file — 'host=db.internal\\nport=5432\\npassword=secret' — and compute an HMAC-SHA384 Base64 signature using the key 'config-integrity-key' so I can store it alongside the file to detect future changes."}],"resultDescription":"Returns a Base64-encoded string containing the HMAC-SHA384 digest of the input text computed with the provided secret key. This is a fixed-length, deterministic authentication code that can be used for message integrity verification or authentication.","failureModes":["Empty or missing key (minLength:1 violated) returns validation error","Text exceeds 100,000 character limit returns 413 or validation error","Missing required fields returns 400 bad request","Payment of $0.009 USDC not provided or declined returns 402 Payment Required","Malformed JSON body returns 400"],"whenToPreferThis":"Choose this endpoint when you need HMAC-SHA384 specifically (stronger than SHA256) and want the output as Base64. If cost is a concern, try the free sandbox endpoint at /v1/sandbox/hmac-sha384-base64 first. Prefer this paid endpoint for production use or when the sandbox is unavailable.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-02T06:50:16.176Z","isFirstParty":false,"canonicalSlug":"hmac-sha384-base64-signer-73d08234"}