This directory contains the Python implementation of the Google Pay PSP client library. It currently covers 4 PSPs — Adyen, Checkout.com, Square, and Stripe. More PSPs will be added as official Python libraries or REST integrations are introduced.

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

python -m unittest discover -s tests

Every PSP module exposes a pay(config, order) method. order requires a total, currency, and either a raw Google Pay paymentResponse or an already-extracted paymentToken.

from psp_client import clients, PaymentValidationError

# PSP-specific configuration, in this case Stripe.
config = {
    "secretKey": "sk_test_...",
}

# An order requires a total, currency, and client-side response from the Google Pay API.
order = {
    "total": 100,
    "currency": "USD",
    "paymentResponse": payment_response,  # raw response from the Google Pay API
}

try:
    response = clients["stripe"].pay(config, order)
    print(response)  # PSP-specific response
except PaymentValidationError as err:
    print(err.error)  # validation message
except Exception as err:
    print(err)  # PSP-specific error

• Adyen
• Checkout.com
• Square
• Stripe

1. Add a new module to psp_client/handlers/. It should export a single pay(config, order) function that performs the charge and returns the PSP's response, raising on failure.
2. Register it in the clients dict in psp_client/__init__.py.
3. The order passed to your handler has already been validated and normalized by psp_client/order.py — you can rely on:
   • order["totalInt"] — the total amount in the smallest possible unit (e.g. cents for USD)
   • order["totalFixed"] — the rounded total amount as a fixed-precision decimal string
   • order["paymentToken"] — the Google Pay token, JSON-decoded into a dict when possible (left as a raw string otherwise, e.g. for PSPs like Square whose token is a plain nonce)