python-getpaid-paynow

Paynow payment processor for python-getpaid ecosystem. Paynow is a modern Polish payment provider and a subsidiary of mBank.

Architecture

The plugin is split into two layers:

• PaynowClient -- low-level async HTTP client wrapping the Paynow V3 REST API. Uses httpx.AsyncClient with API Key authentication and HMAC-SHA256 request signing. Can be used standalone or as an async context manager for connection reuse.
• PaynowProcessor -- high-level payment processor implementing BaseProcessor. Orchestrates payment creation, callback/notification handling, status polling, and refunds. Integrates with the getpaid-core FSM for state transitions.

Key Features

• Create payment -- register a payment and get a redirect URL
• Notification handling -- verify HMAC-SHA256 signature and process status changes
• Status polling -- fetch current payment status via API (PULL flow)
• Refund -- create, check, and cancel refunds
• Payment methods -- retrieve available payment methods
• Sandbox mode -- full support for testing environment

Note: Paynow does not support pre-authorization flows. Immediate capture is used for all transactions. The charge() and release_lock() methods raise NotImplementedError.

Supported Currencies

The processor supports the following 4 currencies:

• PLN (Polish Złoty)
• EUR (Euro)
• GBP (British Pound)
• USD (US Dollar)

Installation

Install the package using pip:

pip install python-getpaid-paynow

Quick Usage

Standalone Client

import anyio
from decimal import Decimal
from getpaid_paynow import PaynowClient

async def main():
    async with PaynowClient(
        api_key="your-api-key",
        signature_key="your-signature-key",
        api_url="https://api.sandbox.paynow.pl",
    ) as client:
        # Create a payment
        response = await client.create_payment(
            amount=Decimal("49.99"),
            currency="PLN",
            external_id="order-001",
            description="Order #001",
            buyer_email="buyer@example.com",
            continue_url="https://shop.example.com/return/order-001",
        )
        redirect_url = response["redirectUrl"]
        print(f"Redirect buyer to: {redirect_url}")

anyio.run(main)

With python-getpaid

Register the plugin via entry point in pyproject.toml (if not using the pre-packaged version):

[project.entry-points."getpaid.backends"]
paynow = "getpaid_paynow.processor:PaynowProcessor"

Then configure in your project settings:

GETPAID_BACKEND_SETTINGS = {
    "paynow": {
        "api_key": "your-api-key",
        "signature_key": "your-signature-key",
        "sandbox": True,
        "notification_url": "https://your-site.com/payments/{payment_id}/callback/",
        "continue_url": "https://your-site.com/payments/{payment_id}/return/",
    }
}

Configuration Reference

Key	Type	Default	Description
api_key	str	required	API key from Paynow merchant panel
signature_key	str	required	Signature key for HMAC calculation
sandbox	bool	True	Use sandbox or production API
notification_url	str	""	Notification URL template; use {payment_id} placeholder
continue_url	str	""	Return URL template; use {payment_id} placeholder

Requirements

• Python 3.12+
• python-getpaid-core >= 3.0.0a2
• httpx >= 0.27.0

Links

• Core Library: python-getpaid-core
• Official Paynow Documentation: docs.paynow.pl
• GitHub Repository: django-getpaid/python-getpaid-paynow

License

This project is licensed under the MIT License.

Credits

Created by Dominik Kozaczko.