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Web Evidence
x402
Web Evidence is a paid API for AI agents from api.williamrobinson.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).
Fetches and extracts the readable content of a web page as Markdown, with integrity hash, for use as verifiable evidence
Price / call$0.01
Success—
StatusUnknown
How this service works
Web Evidence ($0.01/call), OpenSCAD Print Validation ($0.05/call), Spreadsheet Modification & Audit ($0.05/call), Packing & Shipping Engineer ($0.05/call), Game-Asset Technical Artist ($0.10/call), PCB Fabrication Engineer ($0.25/call), Software Failure Reduction Lab ($0.50/call), Laboratory-Protocol Compiler ($0.15/call), Video Finishing & Localization ($0.50/call), Print Prototype Engineer ($0.15/call), Garment-Pattern Engineer ($0.10/call), Product-Label Artwork Compiler ($0.15/call) and Notarized Website Capture ($10.00/call), settled in USDC on Base mainnet over HTTP 402. No API keys, no accounts. Price: $0.01 (10000 atomic USDC per call), settled over HTTP 402 (x402, scheme "exact", EIP-3009). How to pay: an unpaid POST answers 402 with a base64 `payment-required` header describing an exact transfer of 10000 atomic USDC on eip155:8453 (asset 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913) to 0x26026370fe8b2bb17af9092a17691c76519366da. Sign the EIP-3009 authorization, attach it in the `payment-signature` header, and retry the identical request. Invalid requests are never charged. - Settlement: eip155:8453 / 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913 / 0x26026370fe8b2bb17af9092a17691c76519366da
Output
A JSON object containing: the page title, detected language, and full readable content as Markdown; the HTTP status, final (post-redirect) URL, original requested URL, and ISO timestamp of retrieval; load and extraction timing in milliseconds; a SHA-256 hash of the extracted content and the extraction engine version for integrity verification; and any warnings encountered during extraction.
Example use cases
Legal evidence snapshot of webpage
“Grab the full readable content of https://news.example.com/article/123 as markdown and give me the SHA-256 hash so I can prove what it said today if it changes later.”
Research: extract article text
“Pull the main article text from https://en.wikipedia.org/wiki/Photosynthesis as markdown, up to 20000 characters, so I can summarize it.”
Monitor terms of service changes
“Fetch the content of https://company.com/privacy-policy as markdown and include all links on the page so I can compare it against the version from last month.”
Technical details
Endpoint
POSThttps://api.williamrobinson.dev/v1/web/evidence?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a lightweight, cheap ($0.01/call), cryptographically fingerprinted snapshot of a public webpage's readable content as Markdown — especially for evidence, auditing, or research. Unlike full notarized capture ($10/call on the same platform), this is optimized for fast text extraction with integrity hashing rather than full legal notarization. Prefer this over generic HTTP fetch tools when you need the SHA-256 integrity hash, language detection, and clean Markdown rendering via Chromium-readability.
Side effects
- URL is unreachable or returns a non-200 status — source.status will reflect the HTTP error
- Page behind login or paywall — content may be empty or partial
- URL exceeds 2048 characters — request rejected
- maxChars below 1 or above 30000 — validation error
- Payment not attached — 402 response with payment-required header
- Network timeout during page load — error or empty result
- Dynamic JavaScript-heavy pages may yield incomplete extraction
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | |
| maxChars | integer | |
| includeLinks | boolean | |
| includeAccessibilityTree | boolean |
Output
Schema · Response
{
"type": "json",
"example": {
"page": {
"title": "Example Domain",
"language": "en",
"markdown": "# Example Domain\n\nThis domain is for use in illustrative examples in documents.\n",
"canonical": null
},
"source": {
"status": 200,
"finalUrl": "https://example.com/",
"retrievedAt": "2026-01-01T00:00:00.000Z",
"requestedUrl": "https://example.com/"
},
"timings": {
"loadMs": 0,
"extractMs": 0
},
"warnings": [],
"integrity": {
"sha256": "b6bdcd206468c6a8d071af581b180ce6a96166dddadc59b04acd4ee32a9c2ed3",
"extractionVersion": "chromium-readability-1"
}
}
}Tags
x402
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