There are only a few way to calculate prorations & manage recurring payments.

A comprehensive Ruby SDK for Polar.sh, providing easy integration with their payment infrastructure, subscription management, and merchant services.

PayU.in Payment Gateway integration for ActiveMerchant

Coinbase Commerce integration client for crypto payments

A Ruby SDK for integrating with the Solidgate payment gateway API

This gem provides methods to calculate EMI, total interest, and total payment amount for a given loan principal, interest rate, and tenure.

PayUMoney.com Payment Gateway integration for ActiveMerchant

Use the Tester Stripped API to manage business including payment. customer, product and inventory management.

Activemerchant patch for china online payment platform alipay

Payment Framework focused on Authorize.net CIM for dealing with stored credit card transactions.

Get a list of Federal Reserve E-Payments Routing Directory

Integration with Sadad API! All required resources are included to make your payment with Sadad

Responsible for handling referral links and all referral related operations like capture actions, show partner dashboard, payments etc.

Rails engine for QPay V2 payment API with view helpers and webhook support

Ruby SDK for QPay V2 payment gateway API with auto token management.

Syncs your AR models with Braintree (Payment Gateway) and offers a lightweight reoccurring billing script

This library generates credit card numbers using the Luhn algorithm, suitable for testing payment systems and form validations.

A lightweight Ruby wrapper for the NOWPayments API that handles cryptocurrency payments, invoices, and webhooks

PagoPA Microservice for exposing REST APIs about payment receipts.

A Ruby gem for simulating POS operations against the Lightspeed K-Series API. Generates realistic orders, payments, and transaction data for testing.