AttestPage quickstart: from discovery to your first paid call

Last updated: 2026-10-17

This takes about a minute. Every route is a plain HTTPS POST with JSON. You pay per call in USDC over x402 v2, so there is no account and no API key.

1. Discover

Read the catalogue, then pick a route:

curl -s https://vehcdj664efetfrsolne5umanq.srv.us/llms.txt
curl -s https://vehcdj664efetfrsolne5umanq.srv.us/.well-known/ai-catalog.json
curl -s https://vehcdj664efetfrsolne5umanq.srv.us/openapi.json
curl -s https://vehcdj664efetfrsolne5umanq.srv.us/.well-known/x402

/llms.txt: every route, its price and when to use it.
/.well-known/ai-catalog.json: the AI catalogue.
/openapi.json: request and response schemas for every route.
/.well-known/x402: the x402 discovery list, with the price and network of each route.

Prices per call in US$:

Route	Price	Use it when
`POST /v1/verify/quote`	US$0.01	you are about to quote a web page as the source of a claim
`POST /v1/verify/quotes`	US$0.02	you hold several quotes from one page
`POST /v1/verify/citations`	US$0.10	you are about to answer with up to 10 cited pages
`POST /v1/verify/text-quote`	US$0.005	you already hold the text and need it matched
`POST /v1/verify/document`	US$0.10	you need a document checked against its source
`POST /v1/fetch`	US$0.002 per URL	you need a web page as clean text
`POST /v1/recheck`	US$0.003	you need to know if a page you read earlier has changed
`POST /v1/check/links`	US$0.005	you are about to give a user links
`POST /v1/check/packages`	US$0.005	you are about to recommend or install a package
`POST /v1/attest`	US$0.002	you need a signed, timestamped receipt that a file or answer existed unchanged

Source: pricing.json. The route prices in this table are the same as the 402 offer.

2. Try it free (optional)

Send the header Quoteproof-Trial: 1 with no payment. Each IP gets 10 trial calls a day, and a trial call takes batches of up to 5 items. Callers that reach the service through the srv.us address without a payer id (no payment header) each get 10 trial calls a day, told apart by their user-agent; a call with none of those headers shares one pool of 10 trial calls a day instead.

curl -s -X POST https://vehcdj664efetfrsolne5umanq.srv.us/v1/verify/quote \
  -H 'content-type: application/json' \
  -H 'Quoteproof-Trial: 1' \
  -d '{"url":"https://www.iana.org/help/example-domains","quote":"These domains may be used as illustrative examples in documents","match":"fuzzy"}'

A batch larger than the trial limit gets the normal 402 offer, as in step 3.

3. Receive the 402

Send the same request with no trial header and no payment:

curl -i -X POST https://vehcdj664efetfrsolne5umanq.srv.us/v1/verify/quote \
  -H 'content-type: application/json' \
  -d '{"url":"https://www.iana.org/help/example-domains","quote":"These domains may be used as illustrative examples in documents","match":"fuzzy"}'

The answer is 402 Payment Required, with error code payment_required, and the offer in the PAYMENT-REQUIRED header. Decode it to read the accepts entry. For verify/quote it lists amount 10000, which is US$0.01 (USDC has 6 decimals). A request with an empty body gets the same 402, so you can read a price before you have real input.

A request that fails validation gets 400 before any payment is asked for, and it is never charged.

4. Pay

Use an x402 v2 client. The plain-fetch script in the plain-fetch example does the offer check, the signature and the retry in one script. Install its packages first, then run it against the service:

ATTESTPAGE_URL=https://vehcdj664efetfrsolne5umanq.srv.us \
ATTESTPAGE_X402_KEY=0x... \
node fetch-x402.mjs https://www.iana.org/help/example-domains "These domains may be used as illustrative examples in documents"

ATTESTPAGE_X402_KEY is the private key of the wallet that pays, and it stays in your process.
Leave ATTESTPAGE_NETWORK unset and the script pays on Base mainnet, in real USDC. Check the amount before you run it.

Raw steps, if you are not using the script:

Check that the offer's network is eip155:8453 and that amount is what you expect.
Sign the offer with your wallet.
Send the same request again with the signed payment in the PAYMENT-SIGNATURE header.

Test first: the same API runs on Base Sepolia at https://s2h6qt73jtzlgbgnnfacln2poq.srv.us, and payments there use free test USDC from a faucet. Set ATTESTPAGE_NETWORK=eip155:84532 in the scripts in examples to pay there.

5. Retry and read the result

The paid retry returns 200. The PAYMENT-RESPONSE header carries the transaction, the payer and the network. The body carries the result and a signed receipt, shortened here:

{
  "result": { "match": "exact", "score": 1, "start": 171, "end": 234, "occurrences": 1 },
  "page": { "http_status": 200, "content_kind": "real", "title": "Example Domains" },
  "advice": "The page loaded and looks like real content.",
  "receipt": "<signed receipt>", "receipt_id": "9fcda5ac…", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}

Check the receipt again at no charge:

curl -s -X POST https://vehcdj664efetfrsolne5umanq.srv.us/v1/receipt/verify \
  -H 'content-type: application/json' \
  -d '{"receipt":"<signed receipt>"}'

Next steps

Worked examples for every route, with request, 402 and result: Worked examples.
Error codes: the error.code in each response.
Limits per route: Limits.
Terms: Terms.