Have integrated PayPal checkout in an ASP.net web application, managed to make the payment and receipt flow, but have some doubts: This is how we have done it: 1. Made a (test) business/seller account on PayPal.com to receive payments 2. With the same email made an account on developer.paypal.com to test the integration 3. Made an APP in the account created in the account created in step 2, got a Client ID and Secret Key (Sandbox), passed the same in the API calls and the functional process was completed Doubts: 1. If I integrate it for different customers in Live mode do I need to create an App in their Business Account and get the Client ID and Secret key ? 2. Business accounts created under Sandbox accounts on developer.paypal.com login had API credentials, where can we use them in the integration ? 3. How is the Personal account created on developer.paypal.com and a personal account created on sandbox.paypal.com different ? 4. I made a sandbox personal, business account in the developer.paypal.com account, and made, received test payments on the same, but their dummy balance under Profile link didn't changed after making, receiving payments am I doing something wrong here ? Any help would be appreciated !