# Vextorium Aleatorio — Cryptographically Secure Randomness API

> Vextorium Aleatorio — Cryptographically Secure Randomness API is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-16).

Generates verifiable random results (coin flip, dice roll, number in range, item selection, or list shuffle) optionally derived from the latest Ethereum block hash for on-chain verifiability.

## Facts

- Endpoint: POST https://api.vextorium.com/aleatorio-pago?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/vextorium-aleatorio-cryptographically-secure-randomness-api-88fd5709
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vDo4TlulZd4Nfdr-Np7KI

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 vextorium-aleatorio-cryptographically-secure-randomness-api-88fd5709 -d '<json body>'
```

Example prompt: Roll 2 six-sided dice for me and make the result verifiable using the Ethereum block hash so anyone can check it.

## When to prefer this

Choose this endpoint when you need cryptographically secure randomness with optional on-chain verifiability via Ethereum block hash — ideal for trustless lotteries, provably fair games, or any scenario where third parties need to independently verify the random outcome. Prefer it over local PRNG when auditability matters, or when you need structured randomness types (coin, dice, range, pick, shuffle) without building your own logic.

## Known failure modes

- Invalid 'tipo' enum value — must be one of moneda, dado, numero, elegir, barajar
- Missing required 'tipo' field in body
- 'opciones' array empty or missing when tipo=elegir or tipo=barajar
- 'maximo' less than 'minimo' when tipo=numero
- Payment failure or insufficient USDC balance for x402 protocol
- Ethereum block hash unavailable when verificable=true is requested

## How this service works

Randomness for agents: flip coins, roll dice, draw numbers in a range, pick from a list or shuffle it. Cryptographically secure by default; with verificable=true it is derived from the latest finalized Ethereum block hash and your seed, so anyone can verify the result.

## Output

Returns a JSON object containing: the randomness type used (tipo), an ISO 8601 timestamp (fecha), the result as an array of numbers or values (resultado), a boolean indicating if the result is verifiable (verificable), and a proof field (prueba) that is populated when verifiable=true, allowing anyone to re-derive the result from the Ethereum block hash and seed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tipo": {
   "enum": [
    "moneda",
    "dado",
    "numero",
    "elegir",
    "barajar"
   ],
   "type": "string"
  },
  "maximo": {
   "type": "integer",
   "description": "Range max, or dice faces (default 6)"
  },
  "minimo": {
   "type": "integer"
  },
  "semilla": {
   "type": "string"
  },
  "cantidad": {
   "type": "integer"
  },
  "opciones": {
   "type": "array"
  },
  "verificable": {
   "type": "boolean"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "tipo": "dado",
  "fecha": "2026-10-02T20:05:01+00:00",
  "prueba": null,
  "resultado": [
   2,
   6
  ],
  "verificable": false
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/vextorium-aleatorio-cryptographically-secure-randomness-api-88fd5709/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)