Livecheck Sentinel check - one-shot URL condition check
Livecheck Sentinel check - one-shot URL condition check. POST /v1/check with {target, condition, baseline_hash?}. Detectors: status_change, keyword, text_diff, numeric_threshold. Returns current observation + fired when comparable. Fixed $0.02 USDC. No watcher created. Not /v1/verify ($0.01) and not Confirm.
20000 (raw units)
price
1
calls / 30d
1
unique payers
2026-09-10
updated
Provider
livecheck.fly.dev · discovered, not yet claimed by its owner
Payment (x402 accepts[])
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0x33693228b706cb30f4b4dbf35f79129a763f91c5",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "20000",
"maxTimeoutSeconds": 300
}
]Output schema
{
"bazaar": {
"info": {
"input": {
"body": {
"baseline_hash": null,
"condition": {
"detector": "status_change",
"params": {}
},
"target": {
"render": "never",
"selector": null,
"type": "url",
"url": "https://boards.greenhouse.io/example/jobs/1842"
}
},
"bodyType": "json",
"method": "POST",
"type": "http"
},
"output": {
"example": {
"condition": {
"detector": "status_change",
"params": {}
},
"confidence": 0.82,
"fired": null,
"id": "chk_01J8Z0K3N4P5Q6R7S8T9V0WCHK",
"observation": {
"canonical_url": "https://boards.greenhouse.io/example/jobs/1842",
"checked_at": "2026-09-10T18:00:00Z",
"hash": "cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc",
"http_class": "2xx",
"http_status": 200,
"signals": [
"apply form present",
"no closure banner"
],
"status": "live",
"summary": "live 2xx (200); apply form present, no closure banner",
"title": "Staff Backend Engineer — Northwind Labs"
},
"price_usd": 0.02,
"receipt": {
"hash": "dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd",
"verify_url": "https://livecheck.fly.dev/v1/receipt/chk_01J8Z0K3N4P5Q6R7S8T9V0WCHK"
},
"target": {
"render": "never",
"selector": null,
"type": "url",
"url": "https://boards.greenhouse.io/example/jobs/1842"
}
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"baseline_hash": {
"description": "Prior observation.hash for status_change. Omit or null on first check.",
"type": [
"string",
"null"
]
},
"condition": {
"description": "detector status_change, keyword, text_diff, or numeric_threshold. text_diff: selector?, ignore[], min_change_ratio. numeric_threshold: selector or jsonpath, op, value, currency?",
"type": "object"
},
"target": {
"description": "URL target. type=url, render=never. selector optional.",
"type": "object"
}
},
"required": [
"target",
"condition"
]
},
"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": {
"properties": {
"condition": {
"properties": {
"detector": {
"enum": [
"status_change",
"keyword",
"text_diff",
"numeric_threshold"
],
"type": "string"
},
"params": {
"type": "object"
}
},
"required": [
"detector"
],
"type": "object"
},
"confidence": {
"type": "number"
},
"fired": {
"type": [
"boolean",
"null"
]
},
"id": {
"description": "Stable check id (chk_ + ULID).",
"type": "string"
},
"observation": {
"properties": {
"canonical_url": {
"type": "string"
},
"checked_at": {
"type": "string"
},
"hash": {
"type": "string"
},
"http_class": {
"type": "string"
},
"http_status": {
"type": "number"
},
"signals": {
"items": {
"type": "string"
},
"type": "array"
},
"status": {
"enum": [
"live",
"closed",
"unknown"
],
"type": "string"
},
"summary": {
"type": "string"
},
"title": {
"type": "string"
}
},
"required": [
"status",
"signals",
"http_status",
"http_class",
"hash",
"summary"
],
"type": "object"
},
"price_usd": {
"type": "number"
},
"receipt": {
"properties": {
"hash": {
"type": "string"
},
"signature": {
"type": "string"
},
"signer": {
"type": "string"
},
"verify_url": {
"type": "string"
}
},
"required": [
"hash",
"verify_url"
],
"type": "object"
},
"target": {
"properties": {
"render": {
"enum": [
"never"
],
"type": "string"
},
"selector": {
"type": [
"string",
"null"
]
},
"type": {
"enum": [
"url"
],
"type": "string"
},
"url": {
"type": "string"
}
},
"required": [
"type",
"url",
"render"
],
"type": "object"
}
},
"required": [
"id",
"target",
"condition",
"observation",
"fired",
"confidence",
"price_usd",
"receipt"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
}Use it
curl
curl "https://livecheck.fly.dev/v1/check" # -> 402 Payment Required, accepts[] lists how to pay # retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid
JavaScript
const res = await fetch("https://livecheck.fly.dev/v1/check");
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://livecheck.fly.dev/v1/check")
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/12328.json, and this resource appears in /discovery/resources and /discovery/search.