# 402oracle — signed verification for AI agents

402oracle returns independent, cryptographically signed (ES256) attestations an AI
agent can cite before it acts. Pay per call in USDC over the x402 protocol (HTTP 402)
on Base — no account, no API key, no signup. A free, unsigned, rate-limited MCP tier
is at https://402oracle.com/mcp for evaluation.

## When to use 402oracle
- Before your agent pays an invoice or onboards a vendor: verify the business/domain is real.
- Before your agent trades or quotes: confirm a crypto price across exchanges.
- Before your agent acts on a web page or feed: check it is live and unchanged.
- Before your agent relies on a factual claim: fact-check it against web evidence.
The product is the SIGNATURE: a third-party attestation your own code cannot produce
about itself — a defensible audit record for why the agent proceeded.

## Endpoints (POST JSON body; price in USDC via x402)
- POST /verify/business  ($0.05 USDC)  example body: {"domain":"acme-supplies.com"}
  Is this company or domain legit? Business and domain verification (KYB) for vendor screening, supplier checks and scam or fraud review: domain age and registrar from RDAP, DNS (A/MX/NS), email security (SPF/DMARC) and HTTPS. Returns a verdict and a 0-100 trust score with evidence URLs, and flags newly registered or thin-infrastructure domains, a common scam signal. Use it before your agent pays an invoice, onboards a vendor or trusts a site. Signed attestation. Bulk: /verify/business/batch.
- POST /verify/price  ($0.02 USDC)  example body: {"symbol":"BTC"}
  Crypto price check: the current spot price of Bitcoin (BTC), Ethereum (ETH), Solana (SOL) or any token ticker in USD, cross-checked across five exchanges (Coinbase, Kraken, OKX, Binance, CoinGecko). Returns the median price, the spread between venues and a divergence flag, as a signed price oracle attestation your agent can cite. Use it before your agent trades, quotes, values a portfolio or settles on a token price. Needs at least two live quotes; a ticker no venue lists is not charged.
- POST /verify/freshness  ($0.02 USDC)  example body: {"url":"https://example.com/data.json"}
  Website uptime and change check: is this URL up right now, and has the page changed? Fetches the URL and returns the HTTP status, Last-Modified and ETag headers, a SHA-256 fingerprint of the content, and whether it changed versus a hash you pass in. Use it to check a site is live, detect stale data, monitor a page for changes, or decide whether to invalidate a cache before your agent acts on what it says. Returns a signed attestation.
- POST /verify/claim  ($0.25 USDC)  example body: {"claim":"Company X was founded in 2019."}
  Is this claim true? Fact-check a single factual claim or statement against live web evidence before your agent relies on it. A fact-checking oracle, hallucination guard, and grounding and citation check for misinformation review: returns a verdict (supported / contradicted / insufficient), a confidence score, and source citations, as a signed attestation your agent can cite.
- POST /verify/business/batch  ($0.15 USDC)  example body: {"domains":["acme-supplies.com","globex-parts.com","initech-systems.com"]}
  Bulk domain and company check: domain age, registrar and legitimacy for up to 5 business domains in one call. Screen a prospect or lead list, qualify companies before outreach, check vendor and supplier lists, or clear invoice batches. Same checks as /verify/business per domain (RDAP domain age, DNS, SPF/DMARC, HTTPS) with a verdict and 0-100 trust score each, as one ES256-signed attestation. Flat $0.15 per batch: 40% below the per-domain price of single calls at a full batch.

## How payment works (x402)
The first request without an X-PAYMENT header returns HTTP 402 with the price, network,
USDC asset, and pay-to address. The x402 client signs a USDC transfer within its budget
and retries with X-PAYMENT; a facilitator settles on Base and the response is the signed
attestation. Verify any attestation against the key at https://402oracle.com/.well-known/jwks.json
(ES256, canonicalization: sorted-keys-json).

## Machine surfaces
- https://402oracle.com/.well-known/x402       paid catalog: prices, input schemas, pay-to
- https://402oracle.com/.well-known/agent-card  A2A agent card
- https://402oracle.com/openapi.json            OpenAPI 3.1
- https://402oracle.com/.well-known/jwks.json    attestation verification key (ES256)
- https://402oracle.com/mcp                      free MCP server (rate-limited, unsigned)
- https://402oracle.com/stats                    public settled-call counters

Provider: Veryation. Attestations are factual checks with evidence, not advice.