Developing and Deploying PayPal Apps

How would you like to be able to get more traffic for your PayPal-based applications? Embed your apps in the PayPal.com site? Have thousands or even millions of customers consider and potentially use your new application?

If that sounds like a great opportunity to you, you need to look closely at PayPal Apps. PayPal Apps allows you to develop a lightweight, web standards based “gadget” that will embed your application functionality into PayPal’s site on a new PayPal Apps tray, making it available to the masses of PayPal account owners.

Intrigued? Good! Let’s dive into the details so you can start developing and deploying a PayPal App of your own.

What is PayPal Apps?

First, a bit of terminology. “PayPal Apps” does not refer to a native smartphone or tablet application (sorry iOS and Android), nor to a client-side Windows or Mac or Linux application. Neither is it a reference to PayPal-based applications in general. It refers very specifically to a HTML, CSS, and JavaScript based software “gadget”, packaged via an XML-based module referred to as the “gadget specification” or “gadget spec”, and served by the PayPal Gadget Server to a customer’s web browser. This gadget runs within the web browser and is rendered in an HTML iframe. Besides communicating back to the PayPal Gadget Server, a PayPal App may only communicate from the browser to one other domain in the network cloud; this domain is specified during App submission and the service running there is referred to as the “service endpoint”.

PayPal Apps are built by developers, tested in the PayPal Sandbox, and submitted to PayPal for review and approval. If approved, they are made available via a PayPal Apps tray on the live PayPal.com site. From there, they will be visible to millions of PayPal customers. Build the right App, and you could see tremendous traffic in short order!

You can read more about what PayPal Apps are and aren’t, as well as things to note as you begin Apps development, via the excellent “Developing a PayPal App” technical overview page.

As I wrote in a recent DevZone blog post, PayPal Apps were launched at Innovate 2010 to much fanfare. There was a good introductory session given on Apps, “PayPal Apps: The Future Starts Here“, and it is worth watching to familiarize yourself with the technology and its use:

You should also read through PayPal Technology Evangelist Rasesh Shah‘s series of blog posts on PayPal Apps. The first installment does a good job of defining Apps and how to get started with them. Read any or all of his four installments by clicking on each of them here: “Getting Started With PayPal Apps“, “Building Your First Hello World PayPal App“, “Making payments from a PayPal App (Gadget)“, and “Building an advanced PayPal App“. And remember his “HelloWorld” example in particular, as we’ll refer to it again later.

If you cut PayPal Apps, it bleeds OpenSocial

If you decide to try your hand at PayPal Apps development, you will want to dig a little deeper under the covers. PayPal wisely chose to build Apps on top of the OpenSocial gadget framework. OpenSocial originally spun out of the Google Gadgets framework as an attempt to guarantee an open alternative to the proprietary Facebook Platform for social application development. By embracing this open model, PayPal has guaranteed maximum transferability of skills and availability of tools with minimum overhead. Very smart.

OpenSocial supports both general purpose (non-social) gadget-based development as well as building and deploying social networking types of applications. For more information on the OpenSocial technologies, please refer to the OpenSocial Foundation’s web site and especially to the OpenSocial specifications page, JavaScript API reference, and Articles & Tutorials (strangely enough titled “My Life”).

Read the full article on the PayPal X Developer Network to learn the details about what is included from OpenSocial in the PayPal Apps framework, the Apps security model and implementation, how to build and deploy a HelloWorld App, and where to turn for more information if you encounter issues. Click here to read the article now.