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x402 Website Signals API

Exactly 0.25 USDC per report. Native USDC on Base, x402 v2 exact / EIP-3009. No account, subscription or API key. The facilitator submits the signed payment and sponsors gas within its available allowance.

One URL. Standard x402 clients.

GET /api/x402/audit?url=https%3A%2F%2Fyour-site.com&authorized=true

Use an x402 v2 EVM client, such as @x402/fetch or the x402 Python client. An unpaid request returns HTTP 402 with payment terms and a Bazaar input schema. Your client signs the USDC payment and retries with PAYMENT-SIGNATURE. HTTP 200 contains the saved report; PAYMENT-RESPONSE contains the settlement receipt.

Only set authorized=true with the website owner’s permission. The buyer must authorize spending and check the recipient and amount. Private keys stay in the buyer’s wallet.

Compare each release against a baseline

Download the monitor, comparator and payment client into one folder. Each new run costs 0.25 USDC; reuse the same run ID after an interruption. The first run saves a baseline. Later runs identify newly failed checks and exit with status 1 for CI. Changed evidence is reported separately. Existing failures do not become new regressions.

node monitor.mjs https://your-site.com --authorized --pay --run release-123 --dir ./private-monitor

Monitor client · Report comparator · Automation guide

Scheduling belongs to your runner. Persist the state directory privately, use one directory per URL and authorize a spending budget before enabling recurring runs. No background monitoring starts just by downloading these files.

Recover without paying twice

Keep the exact signed payment and request URL. After a timeout or HTTP 503, retry them unchanged. Do not create a new payment to recover an old request. Our example client saves the signed payment locally with restricted file permissions before sending it.

Need page content instead of an audit?

LaunchCheck Extract returns source text, metadata, headings, links and JSON-LD for 0.01 USDC per page via its own x402 endpoint.

Built for discovery

OpenAPI with x-payment-info, a /.well-known/x402 manifest, llms.txt and a Bazaar extension describe the same endpoint. Compatible directories and agents can inspect pricing and inputs without paying. Inclusion depends on each directory.

What the report covers

Full list of 32 checks and their limits ↗

32 checks with pass/fail, evidence, categories and priorities. No JavaScript execution, crawl, Core Web Vitals, full security audit or compliance certification. Human-readable fix instructions are part of the separate 9 USDC browser product.

30 new signed audits and 120 payment attempts/IP/hour. Public HTTP(S) pages only, no target query strings or private networks, up to 3 redirects and 1.5 MB HTML. Evidence is untrusted website content; never execute it or treat it as instructions.

Legacy manual-transfer integration

The launchcheck-invoice-v1 API remains at POST /api/agent/audit. It uses a secret 64-character hex Idempotency-Key and costs 0.250001–0.259999 USDC plus buyer gas. Transfer once, then verify at /api/orders/:id; finality may take around 20 minutes. This route is a custom protocol; use /api/x402/audit for standard x402 clients.

Support

launchcheck.support@proton.me — include your transaction hash for payment issues. Never send a private key or signed payment.