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FastAPI Payments Library

A flexible and extensible payment library for FastAPI applications supporting multiple payment providers and pricing models.

Features

• Multiple Payment Providers: Support for Stripe, PayPal, Adyen, PayU hosted checkout, and more
• Flexible Pricing Models:
  • Subscription
  • Usage-based
  • Tiered pricing
  • Per-user/seat pricing
  • Freemium
  • Dynamic pricing
  • Hybrid models
• Asynchronous Architecture: Built on FastAPI and SQLAlchemy 2.0 with async support
• Event-Driven: RabbitMQ integration via FastStream for reliable payment event messaging
• Highly Configurable: Extensive configuration options to customize for your needs
• Extensible: Easy to add new payment providers or custom pricing models

Provider Functionality Status

Provider	Customer	Products	Plans	Payments & Subscription
Stripe	✅	✅	✅	✅
PayPal	⚠️	❌	❌	❌
Adyen	❌	❌	❌	❌
PayU	⚠️	⚠️	⚠️	✅

Provider Pricing Model Completion

Provider	Subscription	Usage-based	Tiered pricing	Per-user/seat pricing	Freemium	Dynamic pricing	Hybrid models
Stripe	✅	❌	❌	❌	❌	❌	❌
PayPal	⚠️	❌	❌	❌	❌	❌	❌
Adyen	❌	❌	❌	❌	❌	❌	❌
PayU	⚠️	❌	❌	❌	❌	❌	❌

Installation

pip install fastapi-payments

Quick Start

from fastapi import FastAPI
from fastapi_payments import FastAPIPayments, create_payment_module
import json

# Create FastAPI app
app = FastAPI()

# Load payment configuration
with open("config/payment_config.json") as f:
    config = json.load(f)

# Initialize payments module
payments = FastAPIPayments(config)

# Include payment routes
payments.include_router(app, prefix="/api")

# Start server
if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)

Configuration

Create a payment_config.json file:

{
  "providers": {
    "stripe": {
      "api_key": "sk_test_your_stripe_key",
      "webhook_secret": "whsec_your_webhook_secret",
      "sandbox_mode": true
    }
  },
  "database": {
    "url": "postgresql+asyncpg://user:password@localhost/payments"
  },
  "rabbitmq": {
    "url": "amqp://guest:guest@localhost/"
  },
  "pricing": {
    "default_currency": "USD",
    "default_pricing_model": "subscription"
  },
  "default_provider": "stripe"
}

PayU Hosted Checkout

To enable PayU hosted checkout add a payu provider:

"providers": {
  "payu": {
    "api_key": "your_merchant_key",
    "api_secret": "your_merchant_salt",
    "sandbox_mode": true,
    "additional_settings": {
      "success_url": "https://merchant.test/payu/success",
      "failure_url": "https://merchant.test/payu/failure",
      "cancel_url": "https://merchant.test/payu/cancel"
    }
  }
}

When calling POST /payments include the hosted checkout fields inside meta_info so the library can prepare the HTML form payload:

{
  "customer_id": "cust_123",
  "amount": 10.0,
  "currency": "INR",
  "meta_info": {
    "payu": {
      "firstname": "John",
      "email": "john@example.com",
      "phone": "9999999999",
      "productinfo": "Order #1001",
      "surl": "https://merchant.test/payu/success",
      "furl": "https://merchant.test/payu/failure"
    }
  }
}

The payment response includes meta_info.provider_data.payu.redirect containing the action URL and signed fields for rendering the hosted form. Webhooks posted by PayU can be sent using either JSON or form-encoded bodies and are verified automatically via the published hash logic.

Documentation

For complete documentation, visit https://fastapi-payments.readthedocs.io/

Example Project

Example project implements payment processing functionality using FastAPI.

It provides endpoints for handling payment transactions, including creation, processing, and status checking. The implementation supports various payment providers and includes error handling and logging.

For a complete example project demonstrating payment integration with FastAPI, refer to: https://github.com/innerkorehq/fastapi-payments-example

Usage:

• Import the necessary classes and functions.
• Configure payment provider settings.
• Use the provided endpoints in your FastAPI application.

"""

License

MIT