x402 and A2A

Examples for calling paid APIs (x402) and A2A agents, with and without payment. The SDK must have a connected signer and RPC when you need to sign or pay (e.g. x402); the signer can be a private key, wallet provider, or other supported signer.

Call a payment-required API (x402)

GET a URL that returns 402; pay with the first accept and use the response.

from agent0_sdk import SDK
import os

sdk = SDK(chainId=84532, rpcUrl=os.getenv("RPC_URL"), signer=os.getenv("PRIVATE_KEY"))
url = os.getenv("X402_DEMO_URL", "https://twitter.x402.agentbox.fyi/search?q=from:elonmusk+AI&type=Latest&limit=5")

result = sdk.request({"url": url, "method": "GET"})
if result.x402Required:
    paid = result.x402Payment.pay()
    print(paid)
else:
    print(result)

import { SDK } from 'agent0-sdk';

const sdk = new SDK({
  chainId: 84532,
  rpcUrl: process.env.RPC_URL ?? '',
  privateKey: process.env.PRIVATE_KEY,
});
const url = process.env.X402_DEMO_URL ?? 'https://twitter.x402.agentbox.fyi/search?q=from:elonmusk+AI&type=Latest&limit=5';

const result = await sdk.request({ url, method: 'GET' });
if (result.x402Required) {
  const paid = await result.x402Payment.pay(0);
  console.log(paid);
} else {
  console.log(result);
}

Message an A2A agent and use tasks

Load an agent and send a message. If the agent returns a task, query it, send a follow-up, cancel, then list and load tasks.

from agent0_sdk import SDK
import os

sdk = SDK(chainId=84532, rpcUrl=os.getenv("RPC_URL"), signer=os.getenv("PRIVATE_KEY"))
agent = sdk.loadAgent(os.getenv("AGENT_ID_PURE_A2A", "84532:1298"))
out = agent.messageA2A("Hello, this is a demo message.")
if not out.x402Required:
    if hasattr(out, "task") and out.task:
        out.task.query()
        out.task.message("Follow-up message.")
        out.task.cancel()
    tasks = agent.listTasks()
    if isinstance(tasks, list) and tasks:
        loaded = agent.loadTask(tasks[0].taskId)
        loaded.query()

import { SDK } from 'agent0-sdk';

const sdk = new SDK({
  chainId: 84532,
  rpcUrl: process.env.RPC_URL ?? '',
  privateKey: process.env.PRIVATE_KEY,
});
const agent = await sdk.loadAgent(process.env.AGENT_ID_PURE_A2A ?? '84532:1298');
const msg = await agent.messageA2A('Hello, this is a demo message.');
if (!msg.x402Required) {
  if ('task' in msg) {
    await msg.task.query();
    await msg.task.message('Follow-up message.');
    await msg.task.cancel();
  }
  const tasks = await agent.listTasks();
  if (Array.isArray(tasks) && tasks.length > 0) {
    const loaded = await agent.loadTask(tasks[0].taskId);
    await loaded.query();
  }
}

Message an A2A agent that requires payment

When the agent returns 402, pay then use the returned message or task response.

from agent0_sdk import SDK
import os

sdk = SDK(chainId=84532, rpcUrl=os.getenv("RPC_URL"), signer=os.getenv("PRIVATE_KEY"))
agent = sdk.loadAgent(os.getenv("AGENT_ID_A2A_X402", "84532:1301"))
result = agent.messageA2A("Hello, please charge me once.")
if result.x402Required:
    paid = result.x402Payment.pay()
    print(paid)
else:
    print(result)

import { SDK } from 'agent0-sdk';

const sdk = new SDK({
  chainId: 84532,
  rpcUrl: process.env.RPC_URL ?? '',
  privateKey: process.env.PRIVATE_KEY,
});
const agent = await sdk.loadAgent(process.env.AGENT_ID_A2A_X402 ?? '84532:1301');
const result = await agent.messageA2A('Hello, please charge me once.');
if (result.x402Required) {
  const paid = await result.x402Payment.pay();
  console.log(paid);
} else {
  console.log(result);
}

See the x402 and A2A usage guides for more.