This document is a step-by-step procedure instructing you how to integrate Google Checkout with the custom shopping cart on your website. It assumes that you have an existing custom cart and want to integrate Google Checkout with it using the HTML API. As explained below, integrating requires programming skills to modify your server code.
This procedure uses the HTML API. If you're unsure whether you should be using the HTML or XML API, see Choosing Between HTML and XML API.
Objective - When you're done, you will have added a Google Checkout button and supporting code to your existing shopping cart on your website so that customers can click to sign up and place orders through Google Checkout.
Buyer experience - When the buyer clicks the Google Checkout button, your site must send to Google a Google Checkout shopping cart with the list of items the buyer has selected, including prices, descriptions, taxes and shipping. Google Checkout then presents a "Place order" page with the provided information to the buyer. After the buyer chooses a credit or debit card and clicks the "Place your order now" button, Google Checkout accepts the order and sends it to the Order Inbox of your Google Checkout account. For a view of this navigation from the buyer's perspective, see Google Checkout Buyer Experience.
Will this procedure work for my site? The easiest way to determine whether this procedure will work for you is to ask the developer of your custom shopping cart if that code can be modified to work with Google Checkout. For this to be possible, your shopping cart must allow programmatic access to the items in it. Your cart contains the buyer's complete order — your developer needs to write server code to copy the buyer's items from the custom cart and write them out to an HTML form (client-to-server) or HTTP message (server-to-server) and send it to Google Checkout. Have your developer look at Step 7 for more details.
Custom carts - Typically, only custom carts have that kind of internal access to the shopping cart. Carts built by third parties for general use are typically closed and not customizable by merchants &mdash those carts either come with Google Checkout support built-in (these are the Google Checkout eCommerce partners), or not (in which case you can only ask them to add support for Google Checkout).
Procedure summary:
Technical skills required:
This symbol 
means the link opens up the page in a new window or tab so when you're done with that step, you can close the window or tab and go on to the next step.
Sign up now (http://checkout.google.com/sell/signup) for a Google Checkout merchant account if you don't already have one.
This is a production (http://code.google.com/apis/checkout/Google_Checkout_Glossary.html#production) account, for processing real world financial transactions. You will need to supply your email address, to which you will be sent an email to confirm. You will also need to supply information that personally identifies you or your business — depending on the country, this might include a credit or debit card number, tax number, registration number or other forms of identification.
Specify a bank account
Follow the instructions Bank account set up and verification (http://checkout.google.com/support/sell/bin/answer.py?hl=en&answer=113730) to get paid once you start bringing in orders.
When you sell through Google Checkout, buyers pay Google Checkout, who then pays you. Before you can get paid, you need to specify a bank account so that you'll be eligible for payouts. This setup can take a few days, so it's good to set it up early.
Allow unsigned carts
Go to the Integration Settings (https://checkout.google.com/sell/settings?section=Integration) page and uncheck the checkbox labeled My company will only post digitally signed carts. Then click the Save button.
Note: A signed cart (http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#signed_cart) is
a shopping cart that has a cryptographically secure digital signature,
which enables Google to verify that your Checkout API request was not altered
before Google received it. You must use the XML API (http://code.google.com/apis/checkout/developer/Google_Checkout_XML_API.html) if you want to post signed shopping carts; the HTML API does not. When using the HTML API, you will need to review all orders before charging customers and fulfilling orders to ensure that the prices and other information in those orders are correct.
Locate and write down your Merchant ID
Write down your Merchant ID, located on the same Integration
Settings (https://checkout.google.com/sell/settings?section=Integration) page.
This is your production (http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#production) Merchant
ID, to be used for actual sales. You will need to specify your Merchant ID in the cart post URL when you go live.
Note: Your Merchant ID is public, but your Merchant Key is not. You should keep your Merchant Key strictly private and never share it anyone. No Google representative will ever ask you for your Merchant Key. Someone who obtains your Merchant Key could tamper with prices in an order and fraudulently purchase items at a steep discount.
The sandbox(http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#sandbox) is a Google Checkout environment that lets you test placing an order without executing real world financial transactions. This step is recommended if you wish to test your order total calculation (i.e., correct item price, tax, and shipping) and shipping availability.
Also, it will assist in helping you implement your order processing system because it allows you to test an end-to-end order without any real world payments.
Using Sandbox for Testing(http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_Sandbox.html)
Note: You don't need to be signed in to any Google Checkout account (sandbox or production) for the rest of these setup steps, except (1) for testing when you place orders from your sandbox buyer account, and (2) to view orders (in your sandbox merchant account).
In this step you create the initial HTML form, which contains the cart information: item names, item prices, item descriptions, tax rules, shipping rates, and the Google Checkout Button.
Use the Interactive Code Demo (http://code.google.com/apis/checkout/developer/interactive_demo.html) to generate an example
HTML form, following these instructions.
The value attributes for Product, Tax and Shipping are merely placeholders to be replaced when you write server code.
(http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#merchant_center) for all transactions, rather than adding tax rules to the HTML form. If that choice isn't suitable, choose one from the drop-down menu. If those aren't suitable, other tax options are available with the tax rules below.
Note: If you specify default-tax-table attributes in the HTML form (such as rate(http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Parameter_Reference.html#tag_rate)), then your Merchant Center tax settings will be ignored.
Note: If you specify shipping attributes in the HTML form, then your Merchant Center shipping settings will be ignored.
(http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_Sandbox.html) if you're testing (see Step 2), or Production (http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#production) if you're going live. Short attribute names - The interactive code demo lets you choose between HTML API short and long attribute names — they are equivalent. We recommend using the short names wherever possible, because they are easier to read and type. However, only the most common attributes have short equivalents. Here is the list of short attribute names:
(http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_How_Checkout_Works.html#short_names)Note: Writing Code - You can start writing and testing server code to generate the above code now, as described in Step 7, before proceeding with the next steps.
If the previous step did not provide you with the tax rules you need, look for other tax rules in HTML Examples for Tax Tables(http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Taxes.html). You can add these rules to the HTML form you created in the previous step. All HTML Parameter Definitions(http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Taxes.html#HTML_Parameter_Definitions) related to tax rules are listed on that page. You will be writing code to generate these rules in Step 7.
The following tax examples are not covered by the interactive code demo:
Example 4: Alternate tax rules (http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Taxes.html#Alternate_Tax_Rules_1)
Example 5: Alternate tax rules for items that are always tax-exempt (http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Taxes.html#Alternate_Tax_Rules_Tax_Exempt)
Example 7: Alternate tax tables for U.K. merchants (http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Taxes.html#Alternate_Tax_Tables_for_UK)
If the interactive demo did not provide you with the shipping settings you need, look for other shipping rules in Shipping and Digital Delivery (http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API.html#shipping_xsd).
The following shipping example is not covered by the interactive code demo of Step 3:
Carrier-Calculated Shipping (http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API_Carrier_Calculated_Shipping.html)
Note: Digital delivery - Digital goods are delivered by sending download instructions. Three examples of email, URL and description-based delivery of download instructions are included under "Product" in the interactive demo (http://code.google.com/apis/checkout/developer/interactive_demo.html).
By adding tags to define the pixel URLs to include and the parameters for Google Checkout to provide, you can track your percentage of sales/conversions(http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#conversion). In addition, conversion tracking is useful for affiliate sales.
Third-Party Tracking -
Learn how to include XML tags in the HTML API (http://checkout.google.com/support/sell/bin/answer.py?answer=64729), then go to
Google Checkout Support for Third-Party Conversion Tracking (http://code.google.com/apis/checkout/developer/checkout_analytics_integration.html). You can track conversions from your website by adding code to your pages that relays page view information.
Note: In the previous four steps you have created a sample of the HTML form you need for Google Checkout. The purpose of this step is for you to copy the content of the custom cart and write it out to the required HTML form or HTTP request.
You need to write server code to copy the buyer's items from the custom cart and write them out to an
HTML form (http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#html_form) (client-to-server) or
HTTP message (http://code.google.com/apis/checkout/developer/Google_Checkout_Glossary.html#http_request) (server-to-server) and send it to Google Checkout.
Note: The interactive code demo in Step 3 lets you switch between the client-to-server and server-to-server options.
Perform one of the following two instructions:
Client-to-server: Configure your form to submit directly from browser to Google Checkout
Write server code to generate HTML form - With this option, you write server code to copy the order information from your custom cart to an HTML form containing the <input> fields you built in the previous four steps. You write the HTML form, including the Google Checkout button, out to your page where you want the Google Checkout button to appear. When the buyer clicks the Google Checkout button, the form's action sends the Google Checkout API request directly to Google Checkout and displays the Place Order page to the buyer. This process is shown in the diagram on the right.
Sandbox - To send your request to the sandbox, you'll need to change the references from https://checkout.google.com to https://sandbox.google.com/checkout in both the form action and button image. You'll also need to update the Merchant_ID portion of the URLs(http://code.google.com/apis/checkout/developer/interactive_demo.html#markup).
Server-to-server: Submit a server-to-server Checkout API request
When you submit a server-to-server Checkout API request, the form on your page that displays the Google Checkout button (http://code.google.com/apis/checkout/developer/Google_Checkout_HTML_API.html#google_checkout_buttons) will submit to a web service running on your site. That service will then create the Checkout API HTTP request to contain product, taxes and shipping information about your buyer's order. Your application will then send the Checkout API HTTP request to Google using HTTP POST. In response, Google will return to you a Google Checkout URL that you will redirect your buyer to for completing the order.
The basic steps for submitting server-to-server requests follow:
Write an application that creates an HTTP request - Write server code that generates an HTTP request with name/value pairs based on the HTML form created in the earlier steps, replacing the placeholder values in the tags with the actual buyer-selected product, tax and shipping information. The names should be from attribute (parameter) names in the HTML API.
Configure the Google Checkout button to submit to your site - Configure the forms on your site that display Google Checkout buttons to submit to a URL on your site that runs the application created in Step i. When the buyer clicks a Google Checkout button, your server will receive an HTTP request at that URL. Your application should then build the Checkout API request for the buyer's order.
Send the request to the Google Checkout server - Send the HTTP request to Google using an HTTP POST request. Please select the appropriate URL for your request from the two choices below.
Sandbox - To send your request to the sandbox, send it to the following URL. You must replace the string MERCHANT_ID with the Merchant ID for your sandbox merchant account (http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_Sandbox.html#Locate_ID_and_Key).
|
https://sandbox.google.com/checkout/api/checkout/v2/merchantCheckoutForm/Merchant/MERCHANT_ID
Production - To send your request to the production environment, send it to the following URL. You must replace the string MERCHANT_ID with the Merchant ID for your production account.
https://checkout.google.com/api/checkout/v2/merchantCheckoutForm/Merchant/MERCHANT_ID
Extract the Google Checkout URL that Google returns to you - If your request contains valid HTML, Google will return a checkout-redirect response. This message identifies the Google Checkout URL where the buyer can complete the order. The following HTML shows a sample checkout-redirect response.
_type=checkout-redirect
&serial-number=c821326e-7caa-4d51-9b2e-48ef7ecd6423
&redirect-url=https://checkout.google.com/buy?o=shoppingcart&shoppingcart=8572098456
Note: The URL may include an ampersand (&) character, encoded as &. Your code should properly decode this character so that the URL to which you redirect the buyer contains only the text "&" and not "&".
Redirect the buyer to the Google Checkout URL - Send a HTTP 302 response to the HTTP request that you received when the buyer clicked the Google Checkout button. The response needs to redirect the buyer to the HTML-decoded URL that you received in Step iv.
To test your Google Checkout implementation, send requests using the sandbox settings specified in Step 7.
Log into your sandbox buyer account (http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_Sandbox.html#Create_Sandbox_Accounts) and place a complete, end-to-end order. Then log into your sandbox merchant account (http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_Sandbox.html#Create_Sandbox_Accounts) and view the order in the Merchant Center.
(http://checkout.google.com/seller/policies.html#4), section 4e)
Note: If you are signed in as a buyer to a production Google Checkout account (not a sandbox account), you should test only up to clicking the Google Checkout Button and viewing the "Place order" page. Clicking the "Place Order" button in production will create a real order. We recommend that you use the sandbox testing environment to place any and all test orders.
Also, please note that merchants are not permitted to make test purchases from themselves using their own accounts. Rather, you'll need to create a separate buyer account from the merchant account created.
To ensure a positive, consistent experience for your customers, please ensure that your site complies with the
Google Checkout API integration checklist (https://checkout.google.com/support/sell/bin/answer.py?answer=72125&query=integration&topic=&type=).
EXTRA: Google Checkout Launch Checklist (http://code.google.com/apis/checkout/developer/Google_Checkout_Basic_HTML_Launch_Checklist.html)
The checklist provides guidelines for Google Checkout button placement, the checkout order flow and branding.
If you've been using the sandbox, you need to make the following changes (as shown in the interactive code demo of Step 3):
Change sandbox URL "https://sandbox.google.com/checkout" to production URL "https://checkout.google.com" in these places:
Change the sandbox Merchant ID to your production Merchant ID from Step 1D.
Once you're sure you can fulfill orders, go ahead and push your site live.
Note: Orders placed using Google Checkout buttons with the HTML API don't allow for digital signature authentication. As always, please review all orders before charging customers and fulfilling orders to ensure that the item prices, total prices, and other information in those orders are correct.
Note: Google Checkout buttons will remain on your website unless you edit your website's HTML to remove them. To avoid buyer confusion, please ensure you can fulfill orders before placing Google Checkout buttons on your website, and remove Google Checkout buttons from your site if you don't intend to fulfill orders any longer.
Congratulations! You have finished Part I. Now you can quickly and easily sell items!
Next you can move on to Part II, where you receive, charge, ship, and get paid for those orders.
You have two options, which you can compare at Checkout Order Processing: Which Option Is Best for Me? (http://code.google.com/apis/checkout/developer/Google_Checkout_Comparison_Part_II.html):
(http://code.google.com/apis/checkout/developer/Google_Checkout_Merchant_Center.html) — use to start receiving orders, charging them against credit and debit cards, shipping orders, and marking them as shipped. (http://code.google.com/apis/checkout/developer/Google_Checkout_Comparison_Part_II.html#custom_processing) — use if you already have an order processing system that you would like to integrate Google Checkout with.After a buyer has placed an order, you have shipped it to them and charged their card, Google then pays you that amount minus a transaction fee. To find out about payment prerequisites and schedules, see:
(http://checkout.google.com/support/sell/bin/answer.py?hl=en&answer=25400) (http://checkout.google.com/support/sell/bin/answer.py?hl=en&answer=89800) (http://checkout.google.com/support/sell/bin/topic.py?topic=12167)