x402 is an open payment protocol from Coinbase built on the HTTP 402 Payment Required status code. A server quotes a price in the 402 response, the client pays it programmatically with a signed stablecoin authorization, and the request goes through. It removes accounts, API keys, and manual billing from machine-to-machine API access.

Announcement

July 11, 2026 · 5 min read

Introducing x402 Support: Agentic Payments for 40+ APIs

Q: How much does an OpenWeb Ninja API call cost over x402?

Most endpoints cost $0.003 per call. AI-model endpoints such as ChatGPT, Gemini, Copilot, Google AI Mode, and AI Answers cost $0.005. Only successful calls are charged, and the exact amount is always quoted in the 402 challenge for the endpoint you hit.

Q: Which networks and tokens does it support?

Native USDC on Base, Polygon, and Arbitrum. Settlement runs through the Coinbase CDP facilitator, which also covers the gas, so the paying wallet only needs USDC.

Q: Do I need an OpenWeb Ninja account or API key?

No. A wallet holding USDC on a supported network is the only requirement. There is no signup, no API key, and no subscription.

Q: Is the data different from the regular OpenWeb Ninja APIs?

No. The x402 endpoints front the same APIs as api.openwebninja.com and return the same JSON. x402 is a payment method, not a separate product.

Q: How do agents discover the x402 endpoints?

Two machine-readable indexes: the discovery manifest at https://x402.openwebninja.com/.well-known/x402 lists every resource with its payment requirements, and https://x402.openwebninja.com/llms.txt describes every API, endpoint, and price in plain text for LLMs.

AI agents can now call any OpenWeb Ninja API and pay for it inside the request itself. Per call, in USDC, with no account, no API key, and no subscription.

Author

Adam Ben-Ayoun

CTO · OpenWeb Ninja

x402 · AI Agents · Agentic Payments

AI agents are good at calling APIs. Getting access to those APIs is the part that still needs a human: someone creates an account, picks a plan, attaches a card, and hands the agent a key to store safely. For an agent that just needs 20 search results right now, that workflow is the bottleneck.

x402 removes it. It is an open payment protocol from Coinbase built on the HTTP 402 Payment Required status code: the server quotes a price in the response, the client pays it programmatically, and the request goes through. Today we are launching x402 support for all 40+ OpenWeb Ninja APIs at x402.openwebninja.com.

Every endpoint we offer (SERP, local business, jobs, e-commerce, real estate, finance, and AI search) is now callable with nothing but a wallet. Most endpoints cost $0.003 per call. AI-model endpoints cost $0.005. Only successful calls are charged.

How a paid call works

1
Call any endpoint, with no auth at all.
The server replies 402 Payment Required. The response carries the payment requirements: the exact price, the accepted networks, and the address to pay.
2
Sign a USDC authorization for the quoted amount.
An EIP-3009 "exact" authorization on Base, Polygon, or Arbitrum. There is no transaction for you to submit: the Coinbase CDP facilitator settles it and pays the gas. Your wallet only needs USDC.
3
Retry the request with the PAYMENT-SIGNATURE header.
You get a 200, the data, and a settlement receipt in the PAYMENT-RESPONSE header.

Here is step 1 for real, against our JSearch API:

curl "https://x402.openwebninja.com/jsearch/search-v2?query=software+engineer+jobs+in+austin"

HTTP/2 402

The 402 challenge, decoded and trimmed to one network:

{
  "x402Version": 2,
  "error": "Payment required",
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:8453",
      "amount": "3000",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "payTo": "0x3e7c9cA818f713F19e126E3B7B37B47dC1411570",
      "maxTimeoutSeconds": 300,
      "extra": { "name": "USD Coin", "version": "2" }
    }
  ]
}

eip155:8453 is Base, and the amount is in USDC's six-decimal units: 3000 means $0.003. The full challenge also lists Polygon and Arbitrum entries. Everything the client needs to pay is in this one response.

Your agent never sees the 402

In practice, a client library handles the challenge-sign-retry loop. With the official x402-fetch package, a paid call is a normal fetch:

// npm install x402-fetch viem
import { wrapFetchWithPayment } from "x402-fetch";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY);

const fetchWithPayment = wrapFetchWithPayment(fetch, account);

const res = await fetchWithPayment(
  "https://x402.openwebninja.com/jsearch/search-v2?query=software+engineer+jobs+in+austin"
);
const results = await res.json();

The response is the same JSON the regular API returns (trimmed here):

{
  "status": "OK",
  "request_id": "5a8e34f1-a27c-49ee-a5b5-45d2b98ee6aa",
  "data": {
    "jobs": [
      {
        "job_id": "GrjRvpGsrjwtgFBuAAAAAA==",
        "job_title": "Senior Front-End Developer",
        "employer_name": "TEKsystems",
        "job_publisher": "TEKsystems Careers",
        "job_employment_type": "Full-time",
        "job_apply_link": "https://careers.teksystems.com/us/en/job/...",
        ...
      },
      ...
    ],
    "cursor": "..."
  }
}

The same pattern exists for Python (pip install x402) and axios, and agent stacks are adopting the protocol directly, so in many setups the agent only needs a funded wallet and the URL.

What's behind the paywall: 40+ APIs

Search & discovery: Web Search, SERP, News, Forums, Images, Video, Shorts, Lens, Reverse Image, Autocomplete, Social Links
AI search & models: AI Answers, AI Overviews, Google AI Mode, ChatGPT, Gemini, Copilot
Local & maps: Local Business Data, Yelp, Trustpilot, Local Rank Tracker, Driving Directions, Waze, EV Charge Finder
Jobs & salaries: JSearch, Jobs Data, Job Salary Data, Glassdoor
Commerce & product: Amazon, Product Search, Walmart, eBay, Costco, Wayfair, Home Depot, Books, Play Store Apps
Real estate: Zillow, Redfin, Real Estate Data
Finance & events: Real-Time Finance Data, Events Search
Contact & enrichment: Website Contacts, Email Search, Web Unblocker

These are the same APIs behind Local Business Data, JSearch, and every other page in our catalog. Same endpoints, same parameters, same JSON. x402 is a payment method, not a separate product.

Built for agents to find on their own

An agent should not need a human to tell it where the data lives, so the catalog is published in two machine-readable forms:

Discovery manifest

Every resource with its full x402 payment requirements: price, networks, and pay-to address. Indexes and wallets can price a call without ever hitting the endpoint.

x402.openwebninja.com/.well-known/x402

llms.txt

A plain-text catalog written for LLMs: every API, endpoint, method, and price, plus the three-step payment flow. Drop it into an agent's context and it can start calling.

x402.openwebninja.com/llms.txt

x402 or an API key?

Both paths hit the same APIs. Pick by who is doing the calling and how often.

	x402	API key
Setup	None. A wallet with USDC.	Free account, key in a header
Best for	Autonomous agents, one-off and bursty calls	Sustained monthly volume, apps, dashboards
Pricing	$0.003/call for most endpoints, $0.005 for AI models	Free tier on every API, plans get cheaper per request at volume
Billing	USDC settled per request, receipt in the response header	Monthly billing by card
Who approves spend	The agent, within its wallet balance	A human, once, at signup

If you call us at volume every month, a subscription is cheaper per request. x402 is for the calls that would otherwise never happen because a signup form stood in the way.