Verify whether a supplied public source page currently supports one atomic factu
Verify whether a supplied public source page currently supports one atomic factual claim. Returns supported, contradicted, or insufficient-evidence plus source snippets, or explicit blocked/unreachable/unsupported states. Not a general fact checker or web search.
Answeringour last check, 2026-09-24
1 of 1checks answered this week
346 msmedian answer time
$0.01listed price per call
$0.01price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://source-claim-proof.mattskowronis.workers.dev/v1/verify
| Category | Search and research |
|---|---|
| Provider host | source-claim-proof.mattskowronis.workers.dev |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 6 from 4 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-24 | valid payment request | 402 | $0.01 | 346 ms |
Example input (from the provider)
{
"body": {
"claim": "The event begins at 7:00 PM.",
"url": "https://example.com/event"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"claim": {
"description": "One atomic factual assertion to check against that source only.",
"maxLength": 500,
"minLength": 3,
"type": "string"
},
"url": {
"description": "Public HTTP or HTTPS source page URL to inspect.",
"maxLength": 2048,
"type": "string"
}
},
"required": [
"url",
"claim"
]
},
"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,
"properties": {
"claim": {
"description": "The claim that was checked.",
"type": "string"
},
"content_hash": {
"description": "Hash of retrieved source content.",
"type": "string"
},
"evidence": {
"description": "Compact source snippets used for the verdict.",
"items": {
"additionalProperties": false,
"properties": {
"evidence_type": {
"description": "Where the snippet came from on the source page.",
"enum": [
"visible_text",
"heading",
"json_ld",
"meta",
"status"
],
"type": "string"
},
"location": {
"description": "Page location of the snippet, or null if unknown.",
"type": [
"string",
"null"
]
},
"polarity": {
"description": "Whether the snippet supports, contradicts, or is neutral.",
"enum": [
"supports",
"contradicts",
"neutral"
],
"type": "string"
},
"text": {
"description": "Source snippet that supports or contradicts the claim.",
"maxLength": 240,
"type": "string"
}
},
"required": [
"text",
"location",
"evidence_type",
"polarity"
],
"type": "object"
},
"maxItems": 3,
"type": "array"
},
"final_url": {
"description": "Final URL after redirects.",
"type": "string"
},
"reasoning_summary": {
"description": "Short machine-readable reason for the verdict.",
"maxLength": 400,
"type": "string"
},
"retrieval_method": {
"description": "How the source page was fetched.",
"enum": [
"direct_http",
"browser_run",
"official_api",
"unsupported"
],
"type": "string"
},
"retrieved_at": {
"description": "UTC timestamp of the check.",
"type": "string"
},
"service_version": {
"description": "Source Claim Proof service version.",
"type": "string"
},
"source_status": {
"description": "verified, blocked, unreachable, unsupported, or insufficient_evidence.",
"enum": [
"verified",
"blocked",
"unreachable",
"unsupported",
"insufficient_evidence"
],
"type": "string"
},
"source_url": {
"description": "Requested source URL.",
"type": "string"
},
"verdict": {
"description": "supported, contradicted, or insufficient_evidence.",
"enum": [
"supported",
"contradicted",
"insufficient_evidence"
],
"type": "string"
}
},
"required": [
"verdict",
"claim",
"source_url",
"final_url",
"source_status",
"evidence",
"reasoning_summary",
"retrieval_method",
"retrieved_at",
"content_hash",
"service_version"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}