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HMAC-SHA384 Base64url Signer
x402
HMAC-SHA384 Base64url Signer is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-29).
Computes an HMAC-SHA384 digest of text using a caller-supplied key and returns it encoded as base64url
Price / call$0.01
Success—
StatusUnknown
How this service works
Call when an agent needs an HMAC-sha384 of text with a caller-supplied key, encoded as base64url. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha384-base64url first.
Output
A base64url-encoded string representing the HMAC-SHA384 digest of the provided text, computed with the supplied key. The response contains the signature ready to be embedded in headers, tokens, or integrity checks.
Example use cases
Signing webhook payloads securely
“I need to sign this webhook body — the text is '{"event":"payment.completed","id":"evt_99"}' — using my secret key 'wh_secret_abc123' with HMAC-SHA384, encoded as base64url so I can include it in the header.”
Generating API request signatures
“My upstream API requires an HMAC-SHA384 base64url signature of the request body 'GET /resource?user=42' using the key 'api-signing-key-xyz'. Can you generate that signature for me?”
Creating integrity tokens for data pipelines
“I want to produce an HMAC-SHA384 base64url digest of the string 'pipeline-run:2024-06-01:dataset-A' with the key 'pipeline-secret-88' so I can attach it as a tamper-proof integrity token.”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/hmac-sha384-base64url?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need an HMAC-SHA384 digest specifically encoded as base64url (URL-safe, no padding issues), rather than hex or standard base64. Prefer this over HMAC-SHA512 variants when the receiving system expects SHA384. Use the free sandbox endpoint (/v1/sandbox/hmac-sha384-base64url) during development to avoid costs; switch to this paid endpoint in production workflows requiring guaranteed compute.
Side effects
- Empty or missing 'key' field returns a validation error
- Empty or missing 'text' field returns a validation error
- Text exceeding 100,000 characters is rejected
- Key exceeding 512 characters is rejected
- Payment failure results in a 402 response; use the sandbox endpoint first to verify behavior
- Malformed JSON body returns a 400 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| key | string | HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored. |
| text | string | 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. |
Tags
x402
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