Which PayPal API should I study for this scenario?

I am working on an application like eBay. The application has a cart page for customers where they can see more than 1 items. The items are there to be paid for. The items are with CheckBoxes so user can select any item they wish to pay against (even multiples). Assuming there are 5 items each having some cost. There is also an image button called "Checkout With PayPal". I want the customer to click on the image buttons after checking some items. Now they should go to PayPal checkout page with details of these items includ开发者_运维知识库ing their price and the like. Actually the whole Invoice should be sent to PayPal showing individual items with their prices.

Once the user will pay for all those items, paypal should report back to me with ReturnURL and some fields making sure they paid. I will modify the database.

Which API will really help me get the most out of the PayPal? I read Express Checkout, it looks what I am looking for but not sure if it's really what I want.

You can use any of the APIs to accomplish what you've stated - it's more a question of your programming comfort level, the level of integration you require (for example, if you're comfortable sending your users to PayPal to pay vs. having them pay in your site, such as with Express Checkout), and how much you're willing to pay monthly / per transaction.

At the most basic level you could easily use Website Payments Standard, and set up an IPN (instant payment notification) pointing to a url on your system where you would do some further processing in an automated fashion. Use caution here as it's pretty easy for a semi-sophisticated user to change quantities or item prices in the cart html before posting to PayPal. You'll have to reconcile things in your IPN url to make sure things weren't changed.

visit the paypal developer network for more information: https://www.x.com/community/home (and yes, x.com is their actual url...looks like spam)

Have you looked at PayPal Website Payments Pro? That carries a $20/month charge and it includes some APIs that will allow you to batch up the items into one payment and then ship the user off to PayPal, it will then redirect back to your site and allow you to confirm payment whilst displaying order summary etc.

I figured out the solution myself. I used PayPal Express Checkout plugin. I wrote ASP.NET plugin myself and it's working like a charm so far!