Payment gateway is an online merchant service provided by the e-commerce application service provider that authorize an individual to accept the credit card or direct payment processing for their e-commerce businesses, online retailers, bricks and clicks or traditional brick and mortar from their clients. Payment gateway providers plays a very crucial role for helping the business merchants to accept the online payments via credit card or direct payments and help you to manage the cash flow. Some of the payment gateway service providers are – PayPal, Stripe, Authorize.Net, Amazon Payments, Braintree, BitPay, WorldPay, SagePay, BlueSnap, 2Checkout and PayU etc.