Google Checkout is still a relative newcomer to the online payment processing world.  They offer a solution comparable with Paypal Website Payments standard.  It allows you to accept payments with buttons, without needing a full blown merchant account.  Its free to signup and just about anyone can get an account.

I’ll teach you what you need to know to setup your Google checkout account.  The settings you’ll want to modify on your account preferences.  A basic rundown of how the buttons work. I’ll show what encryption is used on the XML so you can generate your own buttons on the fly.  You’ll learn to use Instant Notification with Google checkout.  And I’ll give you my free script that does all of the above.  It will allow you to integrate Google Checkout dynamically, without needing to use the checkout API.

There are a few benefits you get by using Google checkout.  My personal favorite, is the Google Checkout badge being displayed on your Adwords ads.  This is almost guaranteed to increase your ads Click Through Rate, even if your customers aren’t primarily using Google Checkout.  The badge just makes your ad stand out more and it gets looked at more often.  Better CTR’s save and make you loads of money.

At the time of this writing, you also get free transactions, with no fees, up to 10 times your monthly AdWords spend.  Standard rates are comparable to Paypal and other online payment processors.  Bottom line is, its easy to add, and you will likely get a couple extra sales out adding Google because there is a growing number of people using Google checkout instead of Paypal.

Once you are approved for an account, add and verify your bank account.  This is how you get paid.  The money goes into your bank account shortly after the purchase goes through on Google Checkout.  Google doesn’t yet offer a debit card like Paypal does, hopefully as it gains traction this will happen.  There is a setting in the preferences that keeps the order from being processed and the funds being captured immediately.  In some cases this is what you want, but if you’re automating your order process, you should probably set this to automatically approve orders.

Like Paypal, you can generate buttons, using Google’s interface.  Their buttons are encrypted though, so its not as easy as just editing items on an html form.  Google uses encrypted XML data via POST, rather than just sending the info plaintext in the form values.  Typically if you want to integrate with a database or a do a cart system, you would need to integrate with the API, unless you can emulate googles encryption.

It is possible, though somewhat of a pain to generate your own buttons without using the API. The formatting of the XML is very picky.  Also the HMAC SHA1 encryption used doesn’t have a built in implementation in PHP nor on most other common scripting languages either.  Its too much to explain here, keep going to the bottom and you’ll see the links to the free google checkout script.  You can see how the HMAC SHA1, XML and encryption is all put together to make buttons.

You can do most things you can with Paypal on your Google checkout buttons.  You can setup a return URL or thank you page.  This page is not guaranteed to fire.  The customer has to click through from Google after purchasing to see this page, which may or may not happen.  If you have a task necessary for your order process, handle it via instant notifications, not the thank you page.  Use the thanks page to give confirmation info, and inform the customer of the next steps to get their product.

Google has Instant Payment Notification (IPN) similar to Paypal, they just call it something different.  In the settings look for API Callback URL.  Set it to a URL where the IPN script resides on your server, and it will pass data when an order is completed. In fact, Google actually gives more notifications than just when an order is completed, unlike paypal.  It will send data from failed orders among other cases to your notification page.  In the free Google Checkout script available below, you can see a sample IPN script which will catch the data which gets sent back from Google and show you how to handle it.

Download my free Google Checkout button PHP script

Download google checkout button script here. Easy to use php script creates google checkout buttons in just 1 line of code.  For integration with a database driven dynamic site, or good for stand alone sales pages with only a few products.   No API integration required, this is the easiest way to integrate Google Checkout.

Its easy to extend the script to support additional google checkout button features. Comes with simple copy and paste examples. IPN and Return URL sample scripts are also included.