Verifiable Random pick — string selection with or without replacement bound to a future dr
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.
5000 (raw units)
price
3
calls / 30d
2
unique payers
2026-09-15
updated
Provider
verifiable-random.use.x402atlas.com · discovered, not yet claimed by its owner
Payment (x402 accepts[])
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "5000",
"maxTimeoutSeconds": 300
},
{
"scheme": "exact",
"network": "eip155:137",
"payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
"asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"amount": "5000",
"maxTimeoutSeconds": 300
},
{
"scheme": "exact",
"network": "eip155:42161",
"payTo": "0x8C128f1Ee62Bb5e47867CfbAe2ad89be325Df1b2",
"asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
"amount": "5000",
"maxTimeoutSeconds": 300
}
]Output schema
{
"bazaar": {
"category": "utilities",
"info": {
"input": {
"body": {
"algorithm_version": "drand-hkdf-sha256-v1",
"client_seed": "example",
"count": 2,
"items": [
"red",
"green",
"blue"
],
"replacement": false,
"target_round": 0
},
"bodyType": "json",
"method": "POST",
"type": "http"
},
"output": {
"example": {
"algorithm_version": "drand-hkdf-sha256-v1",
"beacon": {
"chain_hash": "52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971",
"network": "quicknet",
"randomness": "1466a6cd24e327188770752f6134001c64d6efcc590ccc26b721611ad96f165a",
"round": 1,
"scheduled_time": "2023-08-23T15:09:27Z",
"scheme": "bls-unchained-g1-rfc9380",
"signature": "b55e7cb2d5c613ee0b2e28d6750aabbb78c39dcc96bd9d38c2c2e12198df95571de8e8e402a0cc48871c7089a2b3af4b"
},
"example_only": true,
"operation": "pick",
"processed_at": "2023-08-23T15:09:27Z",
"request_hash": "bf26799b7b70582f93b7ab7e9ea1428d812387b32e3177c521ed38f09306abcc",
"result": {
"items": [
"red",
"green"
],
"original_indices": [
0,
1
]
},
"selection_mode": "example_only",
"target_round": 1
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"additionalProperties": false,
"description": "String selection request bound to a future drand round.",
"properties": {
"algorithm_version": {
"default": "drand-hkdf-sha256-v1",
"description": "Optional version guard; when supplied it must match the server's pinned derivation algorithm.",
"enum": [
"drand-hkdf-sha256-v1"
],
"type": "string"
},
"client_seed": {
"default": "",
"description": "Optional public domain-separation label, not secret entropy.",
"maxLength": 256,
"type": "string"
},
"count": {
"description": "Number of values to select.",
"maximum": 1000,
"minimum": 1,
"type": "integer"
},
"items": {
"description": "Candidate strings to select from, at most 131072 UTF-8 bytes combined; duplicate values are allowed and remain distinguishable by original_indices.",
"items": {
"maxLength": 256,
"type": "string"
},
"maxItems": 1000,
"minItems": 1,
"type": "array"
},
"replacement": {
"default": false,
"description": "False selects each input position at most once; true makes independent draws and permits repeated positions.",
"type": "boolean"
},
"target_round": {
"default": 0,
"description": "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.",
"minimum": 0,
"type": "integer"
}
},
"required": [
"items",
"count"
],
"type": "object"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"additionalProperties": false,
"description": "Verifiable Random result and complete drand derivation transcript.",
"properties": {
"algorithm_version": {
"description": "Pinned canonicalization, derivation, and sampling algorithm version required to reproduce the result.",
"enum": [
"drand-hkdf-sha256-v1"
],
"type": "string"
},
"beacon": {
"additionalProperties": false,
"description": "Locally verified drand Quicknet proof used as the public randomness source.",
"properties": {
"chain_hash": {
"description": "Pinned Quicknet chain hash used to fetch and verify the round.",
"enum": [
"52db9ba70e0cc0f6eaf7803dd07447a1f5477735fd3f661792ba94600c84e971"
],
"type": "string"
},
"network": {
"description": "Pinned drand network name.",
"enum": [
"quicknet"
],
"type": "string"
},
"randomness": {
"description": "Lowercase hexadecimal randomness derived from the verified signature.",
"pattern": "^[0-9a-f]{64}$",
"type": "string"
},
"round": {
"description": "Exact verified Quicknet round used for this result.",
"minimum": 1,
"type": "integer"
},
"scheduled_time": {
"description": "Scheduled UTC publication time of the selected round.",
"format": "date-time",
"type": "string"
},
"scheme": {
"description": "Pinned drand signature scheme.",
"enum": [
"bls-unchained-g1-rfc9380"
],
"type": "string"
},
"signature": {
"description": "Lowercase hexadecimal BLS signature verified against the pinned Quicknet public key.",
"pattern": "^[0-9a-f]{96}$",
"type": "string"
}
},
"required": [
"network",
"chain_hash",
"scheme",
"round",
"scheduled_time",
"randomness",
"signature"
],
"type": "object"
},
"example_only": {
"description": "True only in compiled catalog/keepalive examples; live paid results are false.",
"type": "boolean"
},
"operation": {
"description": "Random operation performed by this route.",
"enum": [
"pick"
],
"type": "string"
},
"processed_at": {
"description": "UTC time when the service accepted the request and committed to the round-selection decision.",
"format": "date-time",
"type": "string"
},
"request_hash": {
"description": "Lowercase SHA-256 of your canonical request JSON — retain the exact request body so you can re-derive the result offline.",
"pattern": "^[0-9a-f]{64}$",
"type": "string"
},
"result": {
"additionalProperties": false,
"description": "Operation-specific result derived deterministically from the verified beacon and request hash.",
"properties": {
"items": {
"description": "Selected strings in draw order.",
"items": {
"type": "string"
},
"type": "array"
},
"original_indices": {
"description": "For each selected value, its zero-based position in the input array.",
"items": {
"type": "integer"
},
"type": "array"
}
},
"required": [
"items",
"original_indices"
],
"type": "object"
},
"selection_mode": {
"description": "server_next means the server chose the next safe unpublished round, so you trust its selection chronology; client_fixed means the round is the one you committed to before paying and no other round can be substituted; example_only appears only in catalog examples.",
"enum": [
"server_next",
"client_fixed",
"example_only"
],
"type": "string"
},
"target_round": {
"description": "Echoes the round actually selected for this result; in server_next mode this is the server-chosen round, not the 0 you sent.",
"minimum": 1,
"type": "integer"
}
},
"required": [
"operation",
"algorithm_version",
"selection_mode",
"target_round",
"example_only",
"processed_at",
"request_hash",
"beacon",
"result"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
},
"tags": [
"verifiable-random",
"random-pick",
"random-selection",
"sample",
"drand",
"fair-selection"
]
}
}Use it
curl
curl "https://verifiable-random.use.x402atlas.com/pick" # -> 402 Payment Required, accepts[] lists how to pay # retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://verifiable-random.use.x402atlas.com/pick");
if (res.status === 402) {
const { accepts } = await res.json();
// pay one of accepts[] via an x402 client, then retry with the payment header
}Python
import httpx
res = httpx.get("https://verifiable-random.use.x402atlas.com/pick")
if res.status_code == 402:
accepts = res.json()["accepts"]
# pay one of accepts[] via an x402 client, then retry with the payment headerMachine-readable
Everything on this page is also available as clean JSON at /resources/4492.json, and this resource appears in /discovery/resources and /discovery/search.