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Verifiable Random Pick
x402
Verifiable Random Pick is a paid API for AI agents from verifiable-random.use.x402atlas.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).
Selects one or more strings from a provided list with or without replacement, using a future drand randomness beacon to ensure verifiable, unbiased selection with a reproducible proof transcript.
Price / call$0.005
Success—
StatusUnknown
How this service works
Verifiable Random pick — string selection with or without replacement bound to a future drand round the server waits for (typically 3-6s) and verifies locally, with a reproducible proof transcript.
Output
Returns the selected string(s) from the input list, the drand round number used for randomness, a cryptographic randomness proof transcript that can be independently verified, and enough information to reproduce and confirm the selection outcome.
Example use cases
Provably fair giveaway winner
“I have a list of 50 contest entrants and need to pick 1 winner without replacement. Use verifiable randomness so I can show participants the result was fair — here are the names: [Alice, Bob, Carol, ...]”
Random team assignment from roster
“Randomly pick 5 players from this squad roster without replacement for the starting lineup: Jordan, Morgan, Casey, Taylor, Riley, Drew, Sam, Alex. I need a proof transcript to show it was unbiased.”
Auditable random feature flag rollout
“I need to randomly select 3 feature names from this list to enable in the next experiment — 'dark_mode', 'new_checkout', 'ai_suggestions', 'sidebar_v2', 'inline_search' — with replacement allowed, and give me the drand proof so we can audit the selection later.”
Technical details
Endpoint
POSThttps://verifiable-random.use.x402atlas.com/pick?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need provably fair, auditable random selection from a discrete set of strings — especially for lotteries, giveaways, random assignments, or any scenario where participants must be able to independently verify the randomness was not manipulated. It is superior to pseudo-random alternatives when auditability and trustlessness matter. Prefer the dice endpoint for numeric outcomes or the shuffle endpoint for full permutations.
Side effects
- Timeout if drand beacon is unreachable or delayed beyond expected window
- Invalid input if the list is empty or sample size exceeds list length when replacement is disabled
- Payment failure if x402 payment header is missing or insufficient
- Malformed request if required fields are missing from POST body
- drand verification failure if the beacon round cannot be confirmed locally
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| count | integer | Number of values to select. |
| items | array | Candidate strings to select from, at most 131072 UTF-8 bytes combined; duplicate values are allowed and remain distinguishable by original_indices. |
| client_seed | string | Optional public domain-separation label, not secret entropy. |
| replacement | boolean | False selects each input position at most once; true makes independent draws and permits repeated positions. |
| target_round | integer | 0 asks the server to choose the next safe unpublished round; a positive value makes a client_fixed commitment and must still be safely in the future. |
| algorithm_version | string | Optional version guard; when supplied it must match the server's pinned derivation algorithm. |
Output
Schema · Response
{
"type": "json",
"example": {
"beacon": {
"round": 1,
"scheme": "bls-unchained-g1-rfc9380",
"network": "quicknet",
"signature": "b55e7cb2d5c613ee0b2e28d6750aabbb78c39dcc96bd9d38c2c2e12198df95571de8e8e402a0cc48871c7089a2b3af4b",
"chain_hash": "52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971",
"randomness": "1466a6cd24e327188770752f6134001c64d6efcc590ccc26b721611ad96f165a",
"scheduled_time": "2023-08-23T15:09:27Z"
},
"result": {
"items": [
"red",
"green"
],
"original_indices": [
0,
1
]
},
"operation": "pick",
"example_only": true,
"processed_at": "2023-08-23T15:09:27Z",
"request_hash": "bf26799b7b70582f93b7ab7e9ea1428d812387b32e3177c521ed38f09306abcc",
"target_round": 1,
"selection_mode": "example_only",
"algorithm_version": "drand-hkdf-sha256-v1"
}
}Tags
x402
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