# HMAC Signature Generator

> HMAC Signature Generator is a paid API for AI agents from agent-data-tools.revmesh2074.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).

Computes an HMAC (Hash-based Message Authentication Code) signature for a given message and key using a specified hashing algorithm (SHA-256, SHA-1, SHA-384, or SHA-512)

## Facts

- Endpoint: GET https://agent-data-tools.revmesh2074.workers.dev/hmac?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hmac-signature-generator-0c4e8a50
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4EP1F9upzo6xTuETo2Dln

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability hmac-signature-generator-0c4e8a50
```

Example prompt: Compute an HMAC-SHA256 signature for the message 'hello world' using the secret key 'mysecretkey123' and give me the hex digest.

## When to prefer this

Choose this endpoint when you need a quick, no-account, pay-per-call HMAC computation without setting up a crypto library or server-side code. Ideal for AI agents that need to sign a single message on demand, verify webhook authenticity, or produce a keyed digest as part of a larger workflow — especially when already using the Agent Data Tools suite for other operations.

## Known failure modes

- Missing 'message' or 'key' query parameters returns an error
- Invalid algorithm value (not sha256/sha1/sha384/sha512) may return an error or default to sha256
- Payment failure via x402 results in no charge and no response
- Network timeout on Cloudflare Worker edge

## How this service works

Compute an HMAC of a message with a key using SHA-256 (default), SHA-1, SHA-384 or SHA-512, in hex and base64. Use to check webhook signatures. The key is used only for this call and is not stored.

## Output

Returns a JSON object containing 'hex' (the lowercase hexadecimal HMAC digest string) and 'algorithm' (the hashing algorithm used, e.g. 'sha256'). No authentication token or account is required; the call costs $0.001 USDC on Base via x402 and is only charged on success.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "message",
  "key"
 ],
 "properties": {
  "key": {
   "type": "string",
   "description": "The key"
  },
  "message": {
   "type": "string",
   "description": "The message"
  },
  "algorithm": {
   "type": "string",
   "description": "sha256 (default), sha1, sha384 or sha512"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "hex": {
   "type": "string"
  },
  "algorithm": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hmac-signature-generator-0c4e8a50/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent-data-tools.revmesh2074.workers.dev](https://www.zero.xyz/host/agent-data-tools.revmesh2074.workers.dev/llms.txt)