A Payment gateway tends to offer multiple types of payment services, that provides onsite and offsite options. Onsite payment is processed by a third party API using web services with the information gathered from our site through a checkout form (For example : Credit card/Debit card credentials). Offsite payment method, on the other hand, processes data entered in the payment gateway page. It redirects the users to the processing page of the payment gateway using the checkout form. After the payment is completed, the user will be redirected to the payment page, from where the user can move forward or backward in the checkout process. Here, let's take a look at the creation of custom offsite payment gateway module.