Cryptonly verifies and settles each payment, and pays the network fee. Payments go straight to your wallet. This package plugs Cryptonly into the stock x402 middleware for FastAPI and Flask.

You need a Cryptonly API key with the x402.verify and x402.settle scopes. The quickstart covers getting one.

FastAPI

pip install cryptonly-x402 "x402[fastapi,evm]" fastapi uvicorn

import os

from cryptonly_x402 import CryptonlyFacilitatorClient
from fastapi import FastAPI
from x402.http import PaymentOption, RouteConfig
from x402.http.middleware.fastapi import PaymentMiddlewareASGI
from x402.mechanisms.evm.exact import ExactEvmServerScheme
from x402.server import x402ResourceServer

facilitator = CryptonlyFacilitatorClient(os.environ["CRYPTONLY_API_KEY"])
server = x402ResourceServer(facilitator)
server.register("eip155:8453", ExactEvmServerScheme())

routes = {
    "GET /weather/:city": RouteConfig(
        accepts=PaymentOption(scheme="exact", price="$0.01", network="eip155:8453", pay_to=os.environ["PAY_TO"]),
    ),
}

app = FastAPI()
app.add_middleware(PaymentMiddlewareASGI, routes=routes, server=server)


@app.get("/weather/{city}")
async def weather(city: str):
    return {"city": city, "temperatureC": 21}

PAY_TO must be a wallet you added in the dashboard.

Flask

Install x402[flask,evm] and use the sync classes:

import os

from cryptonly_x402 import CryptonlyFacilitatorClientSync
from x402.mechanisms.evm.exact import ExactEvmServerScheme
from x402.server import x402ResourceServerSync

facilitator = CryptonlyFacilitatorClientSync(os.environ["CRYPTONLY_API_KEY"])
server = x402ResourceServerSync(facilitator)
server.register("eip155:8453", ExactEvmServerScheme())

Sandbox

Pass sandbox=True and use a key from your sandbox account. The sandbox settles on Base Sepolia (eip155:84532) and Solana Devnet.

facilitator = CryptonlyFacilitatorClient(os.environ["CRYPTONLY_API_KEY"], sandbox=True)

Learn more

• Prices in your code: Python, Express and Go examples
• Discovery: list your endpoints for AI agents
• Reference: key scopes, limits and reason codes

License

MIT