x402 Agent Kit

Pay for any API with USDC. The x402 payment SDK for AI agents.

No API keys. No accounts. No KYC. Just a Base wallet with USDC.

Install

pip install x402-agent-kit

Quickstart

import asyncio
from x402_agent_kit import SignalFuse

sf = SignalFuse(wallet_key="0xYOUR_PRIVATE_KEY")
signal = asyncio.run(sf.get_signal("BTC"))
print(signal)

That's it. The client handles x402 payment negotiation automatically -- it intercepts the 402 response, signs a USDC payment on Base, and retries.

Use with any x402 API

PayableClient works with any x402-enabled endpoint, not just SignalFuse:

from x402_agent_kit import PayableClient

client = PayableClient("0xYOUR_PRIVATE_KEY")

# Any x402 API -- the client handles payment automatically
resp = await client.get("https://some-x402-api.com/data")
print(resp.json())

# Or use a base URL
client = PayableClient("0xKEY", base_url="https://some-x402-api.com")
resp = await client.get("/data")

SignalFuse

SignalFuse is a trading signal API built on x402. The SignalFuse class is a convenience wrapper:

sf = SignalFuse(wallet_key="0xKEY")

signal = await sf.get_signal("ETH")     # Latest signal for ETH
regime = await sf.get_regime()           # Macro regime classification
sentiment = await sf.get_sentiment("SOL")  # Sentiment data
batch = await sf.get_batch(["BTC", "ETH", "SOL"])  # Multiple symbols

Framework Examples

CrewAI

from crewai import Agent
from crewai.tools import BaseTool
from x402_agent_kit import SignalFuse
import asyncio

class SignalFuseTool(BaseTool):
    name: str = "signalfuse_signal"
    description: str = "Fetch a trading signal for a crypto symbol via x402."
    wallet_key: str

    def _run(self, symbol: str) -> dict:
        sf = SignalFuse(wallet_key=self.wallet_key)
        return asyncio.run(sf.get_signal(symbol))

tool = SignalFuseTool(wallet_key="0xKEY")
agent = Agent(role="Trader", goal="Find signals", tools=[tool])

See examples/crewai_tool.py for the full example.

LangChain

from langchain_core.tools import BaseTool
from x402_agent_kit import SignalFuse
import asyncio

class SignalFuseTool(BaseTool):
    name: str = "signalfuse_signal"
    description: str = "Fetch a trading signal for a crypto symbol via x402."
    wallet_key: str

    def _run(self, symbol: str) -> dict:
        sf = SignalFuse(wallet_key=self.wallet_key)
        return asyncio.run(sf.get_signal(symbol))

tool = SignalFuseTool(wallet_key="0xKEY")

See examples/langchain_tool.py for the full example.

Why x402?

x402 is a payment protocol built on HTTP status code 402 (Payment Required). When a server returns 402, the client automatically signs a USDC payment on Base and retries the request. The server verifies the payment and returns data.

This means:

• No API keys -- your wallet IS your identity
• No accounts -- no signup forms, no email verification
• No KYC -- permissionless access to any x402 API
• Pay per request -- no subscriptions, no tiers, no overage charges
• Works everywhere -- any HTTP client that supports x402

Compare this to traditional API payment flows (Stripe, MoonPay, etc.) where you need to create an account, add a payment method, manage API keys, handle webhooks for billing events, and deal with subscription tiers. With x402, your agent just needs a wallet with USDC.

Links

• SignalFuse -- Trading signals via x402
• x402 Protocol -- The payment protocol spec
• Base -- The L2 network used for payments

License

MIT