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Getting started with Flask

Start accepting x402 payments in your Flask server in 2 minutes.
You can find the full code for this example here.

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Step 1: Install dependencies

pip install x402 flask python-dotenv

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Step 2: Set your environment variables

echo "ADDRESS=0x...\nFACILITATOR_URL=https://facilitator.payai.network" > .env

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Step 3: Create a new Flask app

main.py
import os
from flask import Flask, jsonify
from dotenv import load_dotenv
from x402.facilitator import FacilitatorConfig
from x402.flask.middleware import PaymentMiddleware
from x402.types import EIP712Domain, TokenAmount, TokenAsset

# Load environment variables
load_dotenv()

# Get configuration from environment
ADDRESS = os.getenv("ADDRESS")
FACILITATOR_URL = os.getenv("FACILITATOR_URL")

if not ADDRESS or not FACILITATOR_URL:
    raise ValueError("Missing required environment variables")

facilitator_config = FacilitatorConfig(url=FACILITATOR_URL)

app = Flask(__name__)

# Initialize payment middleware
payment_middleware = PaymentMiddleware(app)

# Apply payment middleware to specific routes
payment_middleware.add(
    path="/weather",
    price="$0.001",
    pay_to_address=ADDRESS,
    network="base-sepolia",
    facilitator_config=facilitator_config,
)

# Apply payment middleware to premium routes
payment_middleware.add(
    path="/premium/*",
    price=TokenAmount(
        amount="10000",
        asset=TokenAsset(
            address="0x036CbD53842c5426634e7929541eC2318f3dCF7e",
            decimals=6,
            eip712=EIP712Domain(name="USDC", version="2"),
        ),
    ),
    pay_to_address=ADDRESS,
    network="base-sepolia",
    facilitator_config=facilitator_config,
)


@app.route("/weather")
def get_weather():
    return jsonify(
        {
            "report": {
                "weather": "sunny",
                "temperature": 70,
            }
        }
    )


@app.route("/premium/content")
def get_premium_content():
    return jsonify(
        {
            "content": "This is premium content",
        }
    )


@app.route("/public")
def public():
    return jsonify({"message": "This is a public endpoint."})


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=4021, debug=True)

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Step 4: Run the server

flask run
Your server is now accepting x402 payments!

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Step 5: Test the server

You can test payments against your server locally by following the httpx example or the requests example from the x402 repository. Just set your environment variables to match your local server, install the dependencies, and run the examples.

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