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HMAC-SHA224 Base64URL Signer
x402
HMAC-SHA224 Base64URL Signer is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-29).
Computes an HMAC-SHA224 digest of input text using a caller-supplied key and returns it encoded as base64url.
Price / call$0.002
Success—
StatusUnknown
How this service works
Call when an agent needs an HMAC-sha224 of text with a caller-supplied key, encoded as base64url. Exact $0.002 USDC. Prefer unpaid POST /v1/sandbox/hmac-sha224-base64url first.
Output
Returns a base64url-encoded HMAC-SHA224 digest string computed from the provided text and key. The digest is a fixed-length cryptographic authentication code that can be used for integrity verification or message authentication.
Example use cases
Webhook signature verification
“I need to sign the webhook payload 'user.created:{"id":42}' with the key 'wh_secret_abc123' using HMAC-SHA224 and base64url-encode the result so I can attach it as a header.”
API request authentication token
“Generate a base64url HMAC-SHA224 signature for the string 'GET /orders/99?ts=1720000000' using my signing key 'k9Xz2mP7qR' so I can authenticate this API call.”
Data integrity checksum for stored record
“Compute an HMAC-SHA224 of 'invoice:INV-2024-0055,amount:299.00,due:2024-09-01' with key 'inv_integrity_key' encoded as base64url so I can store it alongside the record to detect tampering.”
Technical details
Endpoint
POSThttps://agentshelf.syntexa.ch/v1/hmac-sha224-base64url?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you specifically need HMAC-SHA224 (not SHA256 or SHA512) output encoded as base64url rather than hex. It is ideal for agents that need a simple, stateless, paid cryptographic signing primitive without managing local crypto libraries. Use the free sandbox endpoint (/v1/sandbox/hmac-sha224-base64url) for testing before incurring the $0.002 USDC per-call charge.
Side effects
- Empty or missing key returns validation error
- Text exceeding 100,000 characters is rejected
- Empty text returns validation error
- Key exceeding 512 characters is rejected
- Malformed request body returns 400 error
- Payment failure or insufficient USDC balance blocks the call
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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