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FactStamp

https://factstamp.agentrails.workers.dev/bulk
● healthy search

Use before you name a company in a contract, invoice, filing or supplier record, before you quote a number or date you did not compute yourself, or when you need an LEI or CIK. Paid verification for agents: cited, dated answers with a signed receipt that verifies offline. $0.05 per call in USDC on Base over x402, packs by card.

Category
search
Chains
base, eip155:8453
Price
$0.0200–$5.0000 USDC

Quality grade

How grading works
B 68.0 / 100
Availability 40.0 / 40
Endpoint responded (HTTP 200)
Payability 20.0 / 20
  • ✓ Answers a real HTTP 402 challenge
  • ✓ Publishes a /.well-known/x402 descriptor
  • ✓ Payment address on record
  • ✓ Settlement network declared
  • ✓ Price declared
Demand 8.0 / 40
2 distinct payers, 12 USDC transfers in the last 30 days
Owner verified 0.0 / 3
Nobody has claimed this listing yet
Endpoint last checked 7 h ago. On-chain activity last read 11 d ago. Availability and on-chain demand are both re-probed daily; the grade updates automatically on the next pass.

Paid endpoints

14 resource(s) advertised by this origin.

https://factstamp.agentrails.workers.dev/bulk

Check a whole bibliography or dependency manifest in one round trip, before you rely on the list: up to 12 items at a flat US$0.12 — 1 cent an item, against 2 cents for the same lookups one at a time. Every item is answered by the same door that answers a single call, so the verdicts cannot disagree. Pay per call here, or redeem a prepaid pack code (one answer-pack credit per three items, up to 25 items on that rail).

https://factstamp.agentrails.workers.dev/check

Check a dated figure you are about to act on against the publisher's own series, and receive verified, stale, contradicted or unknown with the as-of date. Call it before committing a number to a page, deck, model or decision. Coverage today is Australian primary sources; anything outside coverage returns unknown rather than a guess.

https://factstamp.agentrails.workers.dev/citation

Check a citation before repeating it. Give a DOI, an arXiv ID or a paper title; the answer says whether the work exists, what it is (title, authors, year, container) and whether it has been retracted. A title that is absent from both Crossref and arXiv returns not_found, and a near title match is never reported as verified. Cited to the source record with its retrieval time. Verdicts: verified, ambiguous, retracted, not_found, unknown.

https://factstamp.agentrails.workers.dev/document

Call it before you send, file or publish a document that quotes figures, names companies or cites papers. Post the text and every checkable claim comes back verified against dated primary sources, as one signed bundle with a per-claim receipt and its licence. Claims we cannot answer are named and never charged, and the preview is free. Verdicts: verified, stale, contradicted, unknown.

https://factstamp.agentrails.workers.dev/entity

Verify whether a legal entity exists and is currently registered, from open primary registers (GLEIF LEI index, US SEC EDGAR). Call it before naming a company in a contract, invoice, filing or supplier record, or when you need an identifier (LEI or CIK) for a company you know only by name. Returns found, ambiguous, not_found or unknown, cited to the register with its retrieval time. A near name match is never reported as a match.

https://factstamp.agentrails.workers.dev/health
https://factstamp.agentrails.workers.dev/mcp

Verify whether a legal entity exists and is currently registered, from open primary registers (GLEIF LEI index, US SEC EDGAR). Call it before naming a company in a contract, invoice, filing or supplier record, or when you need an identifier (LEI or CIK) for a company you know only by name. Returns found, ambiguous, not_found or unknown, cited to the register with its retrieval time. A near name match is never reported as a match.

https://factstamp.agentrails.workers.dev/package

Check a dependency before installing it. Give a package and, optionally, a version with its ecosystem (npm, PyPI, crates.io); the answer says whether that exact version exists, whether it is yanked or deprecated, and every advisory OSV lists against it. A version that was never published returns not_found with the real versions nearest to it. Verdicts: verified, advisory, yanked, not_found, unknown.

https://factstamp.agentrails.workers.dev/samples
https://factstamp.agentrails.workers.dev/series.json
https://factstamp.agentrails.workers.dev/verify
https://factstamp.agentrails.workers.dev/verify
https://factstamp.agentrails.workers.dev/watch

Buy a standing re-check of one citation or one package version, when an answer has to stay true rather than be true once: re-checked every day for 30 days. US$0.50 the month — 1.7 cents a check, under a 2-cent lookup. The first check is answered and signed on purchase, and each real change (a retraction, a new advisory, a yanked version) gets its own signed receipt. Pay per call here, or redeem a prepaid pack code (10 credits). Returns a read URL and a token shown once.

https://factstamp.agentrails.workers.dev/watch/portfolio

Watch a whole list at once, when a bibliography or a dependency manifest has to stay true: up to 25 citations or package versions re-checked every day for 30 days under one token. US$5 a portfolio — 20 cents a reference, under a cent a check. Every reference is answered and signed on purchase, and each real change gets its own signed receipt. Nothing is sent when nothing changed. Pay per call here, or redeem a prepaid pack code (100 credits).

How to call

cURL · x402-fetch / x402-axios will auto-handle 402
curl -X POST https://factstamp.agentrails.workers.dev/bulk
MCP endpoint
https://factstamp.agentrails.workers.dev/mcp
/.well-known/x402.json
https://factstamp.agentrails.workers.dev/.well-known/x402

Listed in

Directories this entry was found in.

x402scan