This week I was working on PayPal integration in Serial Key Manager(http://serialkeymanager.com/). Some time I spent trying to understand how this can be accomplished using a server language, ASP.NET, since I have not been able to find a clear tutorial that would be easy to follow, So, in this guide I am going to outline how the entire process works and provide you with working examples!

1. Setting up the development tools

The first thing you need is to create a PayPal developer account so that you can access this page https://developer.paypal.com/webapps/developer/applications/myapps. When you press on Sandbox accounts to the left of the page, you will have the option to create two types of accounts: Personal or Business

  • Personal account will be used when you buy your product
  • Business account is the account that will receive the payment from the Personal account.

Depending on how much your product will cost, you will have to insert an appropriate amount of money into the Personal account. I think you can have as much as you like since it is only for testing purposes.

2. Creating the button

Now, you will have to create two Views in a Controller, one where you have the button and one where you have the validation mechanism. Let’s start with the button! Put the code below into any View. My View name is IPN in the User controller.

3. Processing the information returned by PayPal

The example code is based on this code. Please take a look at it to see how it is done with several variables.

Now you need to create a new View in the controller, called IPN. Insert the following code:

PayPal provides you with many variables, so I suggest that you take a look at how the response looks like. When you’ve found a value that you would like to save into the database, use the GetPDTValue function to retrieve that value.

Please note down the Activation token found in the Buyers account in Profile>My Selling Tools>Website preferences> Update. Then, enable auto return and payment data transfer. There, you will also find the Activation token which you should add to: