Keywords

{
  "client_ref": null,
  "endpoint": "cheap-errand",
  "next_tasks": [
    {
      "endpoint": "https://x402.hydratrader.ai/v1/cheap-errand",
      "example_body": {
        "input": "x402 lets agents pay for APIs with USDC via HTTP 402.",
        "task": "extract_keywords"
      },
      "method": "POST",
      "price_usd": "0.01",
      "task": "extract_keywords",
      "why": "Ranked keywords from the same text"
    }
  ],
  "ok": true,
  "result": {
    "keywords": null,
    "label": null,
    "meta": {
      "chars_in": 58,
      "model_hint": "fast"
    },
    "sentiment": null,
    "text": "x402 is an HTTP 402 micropayment protocol so agents can pay USDC for API calls."
  },
  "task": "extract_keywords",
  "usage": {
    "latency_ms": 420,
    "price_usdc": "0.01"
  }
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://x402.hydratrader.ai/v1/keywords' \
  -H 'content-type: application/json' \
  --data-raw '{"input":"x402 lets agents pay for APIs with USDC via HTTP 402.","options":{"max_words":40}}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://x402.hydratrader.ai/v1/keywords' \
  -H 'content-type: application/json' \
  --data-raw '{"input":"x402 lets agents pay for APIs with USDC via HTTP 402.","options":{"max_words":40}}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.01 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.01" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.01 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fx402.hydratrader.ai%2Fv1%2Fkeywords&method=POST
const res = await pay("https://x402.hydratrader.ai/v1/keywords", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "input": "x402 lets agents pay for APIs with USDC via HTTP 402.",
    "options": {
      "max_words": 40
    }
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.01 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.01"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://x402.hydratrader.ai/v1/keywords",
        json={
            "input": "x402 lets agents pay for APIs with USDC via HTTP 402.",
            "options": {
                "max_words": 40,
            },
        },
    )
    print(res.status_code, res.text)