# Proof Random API – Free drand Beacon Sampler

> Proof Random API – Free drand Beacon Sampler is a paid API for AI agents from proof-random-api.pn-26f.workers.dev, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-21).

Relays a drand quicknet randomness beacon with nonce-bound reproducible sampling, returning verifiable on-chain randomness that clients must verify via BLS signature.

## Facts

- Endpoint: POST https://proof-random-api.pn-26f.workers.dev/v1/api-qa?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/proof-random-api-free-drand-beacon-sampler-e08e5b1c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ArpTahBIyu-bxeTU4zRcN

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 proof-random-api-free-drand-beacon-sampler-e08e5b1c -d '<json body>'
```

Example prompt: Fetch me a fresh drand quicknet randomness beacon sample — I need a nonce-bound reproducible random value with BLS verification data so I can prove the result is unbiased.

## When to prefer this

Choose this endpoint when you need publicly verifiable, tamper-proof randomness backed by the drand distributed network (quicknet) and want nonce-bound reproducibility for auditability. Prefer it over pseudo-random or centralized RNG services when cryptographic fairness and BLS-verifiable proofs are required — e.g. for lotteries, games, NFT trait assignment, or any selection that must be provably unbiased. It is not suitable for high-volume free randomness needs given the $0.05/call cost.

## Known failure modes

- drand network unreachable or slow — relay may time out or return stale round
- BLS verification failure client-side if signature data is malformed
- Invalid 'expect' enum value causes request rejection
- Payment not provided or insufficient (requires $0.05 USDC via x402) — returns 402 Payment Required
- Missing required 'url' field in POST body causes 400 error

## How this service works

A free drand quicknet beacon relay with nonce-bound reproducible sampling. Client-side BLS verification required.

## Output

Returns a drand quicknet beacon payload including the current round number, the randomness value (hex or base64), and a BLS signature. The nonce-bound sampling makes results reproducible for a given nonce, and clients are expected to perform BLS verification independently to confirm authenticity.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "url"
 ],
 "properties": {
  "url": {
   "type": "string"
  },
  "expect": {
   "enum": [
    "x402",
    "mcp",
    "http"
   ],
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/proof-random-api-free-drand-beacon-sampler-e08e5b1c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from proof-random-api.pn-26f.workers.dev](https://www.zero.xyz/host/proof-random-api.pn-26f.workers.dev/llms.txt)