{
  "slug": "how-to-tell-if-an-x402-endpoint-is-legit",
  "title": "How do I know an x402 endpoint is legit?",
  "description": "Three observable checks show whether an unknown x402 endpoint is live, priced as listed and used by repeat buyers; Ontario's finder runs them for 0.005 USDC.",
  "lead": "Three quick checks tell most of the story about an unknown x402 endpoint: whether it answers now, whether its live price matches its listing, and whether anyone has paid it more than once.",
  "reviewed": "2026-10-29",
  "next_step": "The pages below go deeper on this question.",
  "primary_label": "Read the finder method and limits",
  "primary_path": "/docs/x402-api-finder?utm_content=legit_guide",
  "secondary_label": "Verify one endpoint free",
  "secondary_path": "/verify?utm_content=legit_guide",
  "sections": [
    {
      "heading": "1. Does it answer right now?",
      "paragraphs": [
        "A request without a payment to a working x402 endpoint returns HTTP 402 with a PAYMENT-REQUIRED payload: the price, the network, the asset and the payTo address. A timeout, a server error or a 402 without those fields means the endpoint is not ready to take a payment, whatever its listing says."
      ]
    },
    {
      "heading": "2. Does the live price match the listing?",
      "paragraphs": [
        "Directories record a price at indexing time. The 402 challenge carries the current one. When the challenge asks for more than the directory shows, the listing is stale or the seller has repriced; either way the challenge is the amount that would actually be paid."
      ]
    },
    {
      "heading": "3. Has anyone paid it more than once?",
      "paragraphs": [
        "Bazaar listings carry l30DaysUniquePayers and l30DaysTotalCalls. One or two payers usually means the seller's own activation payment. Repeat calls from the same payers mean someone is using the endpoint. Marketplace counters are reported by the marketplace and can be inflated or frozen, so they are a signal, not proof."
      ]
    },
    {
      "heading": "What Ontario's finder does",
      "paragraphs": [
        "Ontario's x402 API finder (POST /api/x402/find-api, 0.005 USDC on Base) runs these checks across Coinbase's Bazaar for one task. It sends an unpaid request to up to eight candidates, keeps the endpoints that answered with a valid Base USDC challenge within the caller's budget, reports each one's live price, its price drift against the listing and whether the payTo address matches, and ranks by task fit, price and repeat buyers. Up to five results come back. If no endpoint answers, the call returns 404 and no payment is taken.",
        "Ontario does not guarantee endpoint safety or service quality. A result records what the endpoint did at that moment, with a timestamp, and nothing more."
      ]
    }
  ],
  "sources": [
    {
      "label": "x402 docs: the HTTP 402 response",
      "url": "https://docs.x402.org/core-concepts/http-402"
    },
    {
      "label": "Coinbase: discover services in the Bazaar (listing fields)",
      "url": "https://docs.cdp.coinbase.com/x402/buyer/discover-services"
    },
    {
      "label": "Ontario: finder method, limits and settlement rules",
      "url": "https://ontarioprotocol.com/docs/x402-api-finder"
    },
    {
      "label": "Ontario: finder request card",
      "url": "https://ontarioprotocol.com/api/x402/find-api/info"
    }
  ]
}