Difference Between PayPal Standard and PayPal Payments Pro
Both offerings differ from the other in certain aspects.
Transactions via PayPal Standard are processed on PayPal’s site (not your own), and will allow customers to pay with a PayPal balance or credit/debit card.
Essentially, your users will be sent to PayPal from your checkout screen, and you’ll be charged the standard transaction fee for these payments, which is 2.9 percent + 30¢ per transaction. Customers are then directed back to your site after completing the PayPal checkout.
Since checkout is completed on PayPal’s site, you have to rely on PayPal to send payment success and failure notifications back to your store for completed orders using something called an Instant Payment Notification (IPN). Using the PayPal IPN can occasionally be unreliable, which can sometimes result in the invoices not being completed correctly on your store (cases such as when payment was deducted from the user's card, but the invoice still shows unpaid), which is one of the downsides to PayPal Standard.
PayPal Payments Pro
PayPal Payments Pro has a slightly more complicated setup process, but it offers greater liberty in terms of customization.
There are no startup or termination fees with PayPal Pro, but there is a $30 monthly fee along with a per-transaction fee of 2.9 percent + 30¢.
The biggest difference (and benefit!) to using PayPal Pro is that you can customize the entire checkout experience, as customers remain on your site during the checkout process rather than being directed to PayPal to complete checkout or approve payments. This means you can have a streamlined checkout process, with the same branding and layout as the rest of your site.
It is noteworthy that PayPal Pro is only available to merchants in select countries, namely, USA, UK and Canada.