The <accept-merchant-coupons> tag indicates whether customers should be able to apply coupon codes to their order totals. If this tag has a value of true, then Google Checkout will display an option for customers to enter coupon codes. These codes will then be passed to the merchant in a merchant-calculation-callback request.

The <add-merchant-order-number> tag instructs Google Checkout to attach a merchant-assigned order number to an order.

The <add-tracking-data> tag contains a request to add a shipper's tracking number to an order.

The <additional-fixed-charge> tag allows you to specify a fixed charge that will be added to the total cost of an order if the buyer selects the associated shipping option. If you also adjust the calculated shipping cost using the <additional-variable-charge-percent> tag, the fixed charge will be added to the adjusted shipping rate.

The <additional-variable-charge-percent> tag specifies a percentage amount by which a carrier-calculated shipping rate will be adjusted. The tag's value may be positive or negative. For example, if the tag's value is 15, then the carrier's shipping rate will effectively be multiplied by 1.15 to determine the shipping cost presented to the buyer. So, if the carrier shipping rate were $10.00, the adjusted shipping rate would be $11.50 – i.e. $10.00 + ($10.00 X 15%). If the <additional-variable-charge-percent> tag value is negative, the calculated shipping rate will be discounted by the specified percentage.

The <address1> tag identifies the first line of the address to which an order is being shipped.

The <address2> tag identifies the second line of the address to which an order is being shipped.

The <addresses> tag contains information about shipping addresses for an order.

The <adjustment-total> tag contains the total adjustment to an order total based on tax, shipping, gift certificates and coupon codes.

The <allow-us-po-box> tag indicates whether a particular shipping method can be used to ship an order to a U.S. post office (P.O.) box. To prevent a flat-rate shipping option from being offered to customers who are shipping orders to P.O. boxes in the United States, include this tag with a value of false in the shipping-restrictions for the shipping option. The default value for this tag is true.

The <allowed-areas> tag contains a list of regions where a shipping option is available.

The <alternate-tax-rule> tag contains information about a tax rule that should be applied in a particular area. Each tax rule must contain either exactly one <tax-area> tag or exactly one <tax-areas> tag.

The <alternate-tax-rules> tag contains information about the taxes applied in specific areas, such as states, zip codes or postal codes. The <alternate-tax-rules> element contains a list of one or more <alternate-tax-rule> elements. These rules override the <tax-rules> for an order.

The <alternate-tax-table> tag contains information about an individual tax table, which constitutes a set of alternate-tax-rules.

The <alternate-tax-tables> tag contains a list of one or more alternate-tax-table elements. Alternate tax tables override the rules defined in the default-tax-table.

The <amount> tag identifies the amount of money to charge or refund for an order. The tag's value may either be the full amount of the order or a partial amount. If this tag is omitted and as a part of a charge-order command, Google will charge the customer for the full amount of the order. If this tag is omitted as a part of a refund-order command, Google will refund the full order amount to the customer. This tag has one required attribute, which identifies the currency of the amount to be charged or refunded.

The <analytics-data> tag enables merchants that submit server-to-server Checkout API requests to use Google Analytics to track Checkout orders. The Using Google Analytics to Track Google Checkout Orders document explains how to retrieve the appropriate value for this tag.

The <anonymous-address> tag contains a possible shipping address for an order. This address should be used to calculate taxes and shipping costs for the order.

The <applied-amount> tag contains the amount of a coupon or gift certificate that was applied to an order total.

The <archive-order> tag indicates a request to archive a particular order. You would archive an order to remove it from your Merchant Center Inbox, indicating that the order has been delivered.

The <authorization-amount> tag contains the amount that was reauthorized to be charged to the customer's credit card. Google guarantees that these funds will be available for seven days – 168 hours – from the time that the reauthorization takes place.

The <authorization-amount-notification> tag contains information about a successful reauthorization for an order.

The <authorization-expiration-date> tag identifies the time that a credit card authorization for an order expires.

The <authorize-order> tag contains a request to reauthorize an order. There are several possible consequences of the request:

• If the reauthorization is successful, and the customer has not been partially charged for the order, the order's financial-order-state will update to CHARGEABLE.

• If the reauthorization is successful, but the customer has already been partially charged for the order, the order's financial-order-state will update to (or remain at) CHARGED.

• If the reauthorization is unsuccessful, the order's financial-order-state will update to PAYMENT_DECLINED. In this case, the customer will have 72 hours to submit a new card.

The <avs-response> tag contains an Address Verification System (AVS) response.

Possible values for this tag are:

The <backorder-items> command lets you specify that one or more specific items in an order are out of stock.

The <billing-address> tag contains information about the buyer's billing address.

The <buyer-account-age> tag identifies the age, in days, of the buyer's Google Checkout account.

The <buyer-billing-address> tag contains the billing address associated with an order.

The <buyer-id> tag contains an ID that uniquely identifies the user to Google.

The <buyer-language> tag identifies the customer's user interface language. At this time, this value is always en_US.

The <buyer-marketing-preferences> tag contains information about the customer's contact preferences.

The <buyer-shipping-address> tag contains the shipping address for an order.

The <bye> response indicates that Google correctly received a <hello> request.

The <calculate> tag contains details about calculations that the merchant should perform for an order.

The <calculated-amount> tag contains the calculated amount of a coupon or gift certificate.

The <cancel-items> command lets you specify that one or more specific items in an order have been cancelled, meaning they will not be delivered to the customer. You might cancel items from an order for a variety of reasons. For example, an item might be discontinued or a customer might request to remove an item that was mistakenly included in an order.

The <cancel-order> tag identifies an order that should be canceled. A <cancel-order> command sets the financial-order-state and the fulfillment-order-state to canceled.

The <carrier> tag contains the name of the company responsible for shipping the item. Valid values for this tag are DHL, FedEx, UPS, UPS MI, UPS Mail Innovations, USPS and Other. Please note that UPS MI and UPS Mail Innovations both refer to the same UPS service.

The <carrier-calculated-shipping> tag contains information that Google will need to request shipping costs for an order from the shipment carrier. If you include a carrier-calculated shipping method in your Checkout API request, Google will obtain the shipping cost for the order based on the information that you provided and the shipping address selected by the buyer.

The <carrier-calculated-shipping-adjustment> tag communicates to a merchant the carrier-calculated shipping rate that was charged to a buyer.

The <carrier-calculated-shipping-option> tag contains information about a single shipping method for which Google Checkout should obtain shipping costs.

The <carrier-calculated-shipping-options> tag encapsulates information about all of the shipping methods for which Google Checkout should obtain shipping costs.

The <carrier-pickup> tag specifies how the package will be transferred from the merchant to the shipper. Valid values for this tag are REGULAR_PICKUP, SPECIAL_PICKUP and DROP_OFF. The default value for this tag is DROP_OFF.

The <cart-expiration> tag encapsulates information about the date that the cart expires.

The <charge-amount-notification> tag contains information about a successful charge for an order.

The <charge-order> tag identifies an order for which Google should charge the customer. The <charge-order> tag may specify whether the buyer should be charged the full amount or a partial amount.

The <chargeback-amount-notification> tag contains information about a chargeback that Google Checkout processed for an order.

The <checkout-flow-support> tag contains encapsulates information used to help the customer through the checkout process.

The <checkout-redirect> tag encapsulates the URL to which a customer should be redirected when a merchant submits a shopping cart using the server-to-server technique for posting Checkout API requests.

The <checkout-shopping-cart> tag is the root tag for a Checkout API request and contains all checkout-related information.

The <city> tag identifies the city associated with an order's billing or shipping address.

The <code> tag contains the code for a coupon or gift certificate that was applied to an order.

The <comment> tag contains a comment related to a refunded or canceled order.

Note: The maximum accepted length for the tag value is 140 characters.

The <company-name> tag identifies the company to which an order is being shipped. Please note that Google does not currently request this information from customers but may do so in the future. However, until then, this tag will contain an empty value.

The <contact-name> tag identifies the person to whom an order is being shipped.

The <continue-shopping-url> tag contains a URL that allows the buyer to continue shopping after confirming an order.

As a subtag of <postal-area>, the <country-code> tag specifies a country associated with a tax area, shipping restriction or address filter. In all other contexts, the <country-code> tag identifies the country code associated with an order's billing address or shipping address. The value of this tag must be a two-letter ISO 3166 country code.

The <coupon-adjustment> tag contains information about a coupon that was applied to an order total.

The <coupon-result> tag contains information about a coupon used to calculate an order total.

The <cvn-response> tag contains a credit verification value for the order.

Possible values for this tag are:

The <date-time-zone> tag identifies the time zone that will be associated with the start date and end date for the report. The Order Creation Date field in the API output will also specify times in this time zone. This tag's default value is UTC, which correlates to Greenwich Mean Time (GMT).

Please see the Date and Time Gateway for a list of valid time zone values. Please note that you must combine the name of the region (e.g. America) with the locale (e.g. Chicago) in the following format: America/Chicago.

The <default-tax-rule> tag contains information about a tax rule that should be applied in a particular area. Each tax rule must contain either exactly one <tax-area> tag or exactly one <tax-areas> tag.

The <default-tax-table> tag contains the default set of rules that should be used to calculate the tax for an order.

The <deliver-order> tag indicates that Google should update an order's fulfillment order state to DELIVERED. This tag has one required attribute, which identifies the order to be updated.

The <delivery-address-category> tag indicates whether the shipping method should be applied to a residential or a commercial address. Valid values for this tag are RESIDENTIAL and COMMERCIAL.

The <demo-failure> tag enables you to test your handling of Google Checkout error messages. When you send a <demo-failure> request, Google Checkout will always return an error in the synchronous response to your request.

As a subtag of <digital-content>, the <description> tag contains instructions for downloading a digital content item. Please use the <item-description> tag to provide the description of the item being purchased. Note: This field has a maximum length of 1024 characters and may contain HTML tags. (HTML tags must be XML-escaped as described in the Google Checkout Developer's Guide.)

As a subtag of <promotion>, the <description> tag contains information about a promotion that Google applied to an order.

The <diagnosis> tag contains a diagnostic response to an API request. The diagnostic response contains the parsed XML in your request as well as any warnings generated by your request. Please see the Validating XML Messages to Google Checkout section for more information about diagnostic requests and responses.

The <digital-content> tag contains information relating to digital delivery of an item.

The <display-disposition> tag specifies when the buyer will be able to access purchased digital content. The only valid values for this tag are OPTIMISTIC and PESSIMISTIC.

• If the value of the <display-disposition> tag is OPTIMISTIC, then Google will display instructions for accessing the digital content as soon as the buyer confirms the order. We recommend that you only use optimistic delivery if you can easily revoke access to the digital content if Google cannot authorize the customer's credit card.

• If the value of the <display-disposition> tag is PESSIMISTIC, the buyer cannot access purchased digital content until his credit card has been authorized to be charged for the amount of the order.

The default value for this tag is PESSIMISTIC.

The <edit-cart-url> tag contains a URL that allows the buyer to make changes to the shopping cart before confirming an order.

The <eligible-for-protection> tag indicates whether an order is eligible for Google Checkout's payment guarantee policy.

The <email> tag identifies an email address that could be used to contact the person to be billed for an order or the order recipient.

The <email-allowed> tag indicates whether the customer is willing to receive marketing emails from the merchant.

The <email-delivery> tag indicates that the merchant will send email to the buyer explaining how to access the digital content. Email delivery allows the merchant to charge the buyer for an order before allowing the buyer to access the digital content.

The <error> tag contains information about an invalid API request. This information is intended to help you debug the problem causing the error.

The <error-message> tag contains a message that describes why an API request caused an error.

The <excluded-areas> tag identifies a list of regions where a shipping option is not available.

The <fax> tag identifies a fax number that can be used to contact the person to be billed for an order or the order recipient. Please note that Google does not currently request this information from customers but may do so in the future. However, until then, this tag will contain an empty value.