# GeekVault HMAC Generator

> GeekVault HMAC Generator is a paid API for AI agents from api.geekvault.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-27).

Computes an HMAC (Hash-based Message Authentication Code) for a given message and secret key using a specified hash algorithm (default SHA-256).

## Facts

- Endpoint: GET https://api.geekvault.dev/dev-tools/v1/hmac?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/geekvault-hmac-generator-44ba1ca6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sv1mMDiuD2MDza6UFfM8t

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 geekvault-hmac-generator-44ba1ca6
```

Example prompt: Compute an HMAC-SHA256 signature for the message 'order_id=12345&amount=99.99' using the secret key 'mysecretkey123'.

## When to prefer this

Choose this endpoint when an AI agent needs to compute HMAC signatures on-the-fly without managing cryptographic library dependencies, installing packages, or setting up API keys. Ideal for serverless agents, sandboxed environments, or quick one-off signing tasks where paying $0.002 USDC per call is more practical than running crypto code locally. Prefer over local computation when the execution environment lacks native crypto support.

## Known failure modes

- Missing required 'key' parameter returns a validation error
- Missing required 'message' parameter returns a validation error
- Unsupported algorithm value may return an error or fall back to default
- Payment failure via x402 results in 402 response before computation
- Empty string key or message may produce unexpected but valid HMAC output

## How this service works

Network, docs, image, web, and dev utility tools paid per call via x402. No signup, no API keys, no subscriptions — just USDC on Base.

## Output

Returns a JSON object containing the HMAC hex digest string and the algorithm used (e.g. sha256). The 'hmac' field holds the computed authentication code and 'algo' confirms which hash algorithm was applied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "key",
  "message"
 ],
 "properties": {
  "key": {
   "type": "string",
   "description": "Clave secreta."
  },
  "algo": {
   "type": "string",
   "description": "Algoritmo de hash. Por defecto `sha256`."
  },
  "message": {
   "type": "string",
   "description": "Mensaje a autenticar."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "algo",
  "hmac"
 ],
 "properties": {
  "algo": {
   "type": "string"
  },
  "hmac": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/geekvault-hmac-generator-44ba1ca6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.geekvault.dev](https://www.zero.xyz/host/api.geekvault.dev/llms.txt)