I’ve just upgraded a clients payment system to use the Paypal API. One new feature that I like is the API signature option for verification.
Previously you had to download and install a server side certificate to verify payments through the API. This was quite easy to do but you have quite a number of things to do to get the certificate installed etc. There are certainly some management issues when you are dealing with a number of sites.
With the API signature, you call the web service with an signature string that PayPal generates for you and you can do all your verification on the client side. It’s easy to setup multiple sites using this method.
If you’re thinking of upgrading, download the 4.2 api sdk files and use the paypal_base.dll and log4net.dll files. Then simply modify your Profile code to call createAPISignature.
Then set your username, password, environment and signature and away you go!
The only thing I’ve found time consuming with configuring and using the PayPal api is setting up the sanbox accounts and some of the documentation could be better.
On the whole its pretty darn good though and the Payments Pro solution only costs $20 per month plus transaction fees.