Pricing & payments

Tiers #

Mainnet prices sit at market rates: $0.01 per call is in line with CoinGecko, CoinMarketCap and Nansen per-call data plans, and a Pro run costs less than the five to twenty calls it replaces. Current prices and the seller address are always published at /v1/status.

What is live today #

How x402 works #

x402 uses the HTTP status 402 Payment Required. An agent needs only a Cardano wallet:

1. Call the endpoint

   Without payment, a paid endpoint answers 402. The PAYMENT-REQUIRED header (base64 JSON) says what to pay, in what asset, and to which address; the body repeats it in plain words.

2. Pay

   The agent builds and signs a Cardano transaction for the exact amount, but does not broadcast it. @x402/fetch with @x402/cardano does this automatically within a spending cap you set.

3. Retry with the signed payment

   The agent repeats the request with the PAYMENT-SIGNATURE header. CoinGraph's facilitator verifies the transaction, the answer is computed, the facilitator broadcasts the payment, and the answer is released with a PAYMENT-RESPONSE receipt carrying the transaction id.

{
  "x402Version": 2,
  "error": "Payment required",
  "resource": {
    "url": "https://coingraph.ai/api/v1/agents/trade-gatekeeper",
    "description": "Run a CoinGraph agent (Premium tier, 5 tADA)",
    "mimeType": "application/json",
    "serviceName": "CoinGraph"
  },
  "accepts": [
    {
      "scheme": "exact",
      "network": "cardano:preprod",
      "amount": "5000000",
      "asset": "lovelace",
      "payTo": "addr_test1…",
      "maxTimeoutSeconds": 600,
      "extra": {
        "confirmationPolicy": {
          "l1Confirmations": -1
        }
      }
    }
  ]
}

{
  "success": true,
  "payer": "addr_test1qrwcm2ks…szndmw",
  "transaction": "d3a147217859d56695edf6135e4c34c5b483efa120052e7bde4215b39bd1d477",
  "network": "cardano:preprod",
  "extra": {
    "status": "mempool",
    "confirmations": -1
  }
}

A whole round trip takes a few seconds. That transaction on Cardanoscan. The facilitator is not custodial: it only verifies and broadcasts a transaction the agent has already signed, and never holds funds.

Pay from code #

Packages: @x402/fetch, @x402/cardano and @x402/core, version 2.26.0.

import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { ExactCardanoScheme } from "@x402/cardano/exact/client";
import { toClientCardanoSigner } from "@x402/cardano";

// A preprod wallet with some tADA (faucet: docs.cardano.org/cardano-testnets/tools/faucet)
const signer = toClientCardanoSigner({
  mnemonic: process.env.CARDANO_BUYER_MNEMONIC!,
  network: "cardano:preprod",
  provider: { blockfrost: { baseUrl: "https://cardano-preprod.blockfrost.io/api/v0", projectId: process.env.BLOCKFROST_PROJECT_ID! } },
});

const client = new x402Client()
  .register("cardano:*", new ExactCardanoScheme(signer))
  // Never pay more than 12 tADA for one call.
  .setSpendControls({ allowedAssets: [{ network: "cardano:*", asset: "lovelace", maxAmountPerPayment: "12000000" }] });

const payingFetch = wrapFetchWithPayment(fetch, client);

// 402 → pay → retry happens inside payingFetch.
const res = await payingFetch("https://coingraph.ai/api/v1/agents/trade-gatekeeper", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ token: "solana", size_usd: 5000, side: "buy" }),
});
const { data } = await res.json();          // { verdict: "ALLOW", summary, reasons, verify_url, … }
const receipt = res.headers.get("PAYMENT-RESPONSE"); // base64 JSON with the Cardano transaction id

The same buyer is in the repository as scripts/x402-buyer.ts.

Confirmation policy #

On preprod, CoinGraph releases the answer once its facilitator has broadcast the payment and the node accepted it (l1Confirmations: -1), because preprod blocks can be minutes apart. For real value on mainnet the policy would require block inclusion or depth, which the same code supports by changing one setting.

Free allowances #

Design partners #

Early integrators (teams building agents, wallets or treasuries) get a free key in exchange for feedback, and use it instead of paying per call: send it as Authorization: Bearer cg_…. Write to ajay@coingraph.ai.

Masumi #

Masumi is Cardano's agent-payment and registry protocol; Sokosumi is its marketplace, where companies hire AI “Coworkers” per Task. CoinGraph Crypto Analyst is registered on Masumi and hired on Sokosumi for 1 test USDM per Task (USDM is a USD stablecoin on Cardano; the test version runs on preprod), held in escrow until the result is delivered, with the result hash recorded on chain. See Hire on Sokosumi.