Paypal Express Checkout 2012 Integration Guide
Express Checkout - 2012 - Integration Guide PP_ExpressCheckout_IG_2012 Free User Guide for PayPal Software, Manual
2015-07-27
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PayPal Express Checkout Integration Guide Last updated: August 7, 2012 PayPal Express Checkout Integration Guide Document Number: 100010.en_US-20120807 © 2012 PayPal, Inc. All rights reserved. PayPal is a registered trademark of PayPal, Inc. The PayPal logo is a trademark of PayPal, Inc. Other trademarks and brands are the property of their respective owners. The information in this document belongs to PayPal, Inc. It may not be used, reproduced or disclosed without the written approval of PayPal, Inc. Copyright © PayPal. All rights reserved. PayPal S.à r.l. et Cie, S.C.A., Société en Commandite par Actions. Registered office: 22-24 Boulevard Royal, L2449, Luxembourg, R.C.S. Luxembourg B 118 349 Consumer advisory: The PayPal™ payment service is regarded as a stored value facility under Singapore law. As such, it does not require the approval of the Monetary Authority of Singapore. You are advised to read the terms and conditions carefully. Notice of non-liability: PayPal, Inc. is providing the information in this document to you “AS-IS” with all faults. PayPal, Inc. makes no warranties of any kind (whether express, implied or statutory) with respect to the information contained herein. PayPal, Inc. assumes no liability for damages (whether direct or indirect), caused by errors or omissions, or resulting from the use of this document or the information contained in this document or resulting from the application or use of the product or service described herein. PayPal, Inc. reserves the right to make changes to any information herein without further notice. Contents Chapter Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 About This Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Where to Go for More Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Documentation Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Chapter 1 Getting Started With Express Checkout . . . . . . . . . . . 9 Key Features of Express Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 The Express Checkout Experience . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Supported Countries and Currencies . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Relationship Between Express Checkout and Shopping Carts . . . . . . . . . . . . . . . 12 Express Checkout Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Implementing the Simplest Express Checkout Integration. . . . . . . . . . . . . . . . . . 13 Obtaining an Express Checkout Button and PayPal Mark. . . . . . . . . . . . . . . . 14 Before You Start Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Setting Up the Express Checkout Transaction . . . . . . . . . . . . . . . . . . . . . 16 Obtaining Express Checkout Transaction Details . . . . . . . . . . . . . . . . . . . . 18 Completing the Express Checkout Transaction . . . . . . . . . . . . . . . . . . . . . 19 Testing an Express Checkout Integration . . . . . . . . . . . . . . . . . . . . . . . . 20 Security Issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Troubleshooting Your Express Checkout Integration . . . . . . . . . . . . . . . . . . . . 25 Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Timeouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Logging API Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Encoding and Decoding Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Express Checkout Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Customizing the Express Checkout User Interface . . . . . . . . . . . . . . . . . . . 27 Settlements and Captured Payments . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Refunds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Recurring Payments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Mobile Express Checkout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Parallel Payments With Express Checkout . . . . . . . . . . . . . . . . . . . . . . . 29 Fraud Management Filters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Express Checkout Integration Guide August 7, 2012 3 Contents Event Notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Dynamic Images Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Express Checkout Instant Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Express Checkout Building Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Express Checkout Buttons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Express Checkout API Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Express Checkout Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Express Checkout Token Usage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Chapter 2 Express Checkout User Interface Requirements . . . . . . 35 Express Checkout Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Checkout Entry Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Payment Option Entry Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 PayPal Button and Logo Images. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Express Checkout Image Flavors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Express Checkout Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Payment Mark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Chapter 3 Related API Operations . . . . . . . . . . . . . . . . . . . 39 Sale Payment Action for Express Checkout . . . . . . . . . . . . . . . . . . . . . . . . . 39 Authorization Payment Action for Express Checkout . . . . . . . . . . . . . . . . . . . . 39 Order Payment Action for Express Checkout . . . . . . . . . . . . . . . . . . . . . . . . 40 Issuing Refunds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Tracking Failed or Pending Requests . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Chapter 4 Integrating Express Checkout With PayPal SDKs . . . . . . 45 Chapter 5 Going Live With Your Express Checkout Integration . . . . 47 Chapter A Obtaining API Credentials . . . . . . . . . . . . . . . . . . 49 Creating an API Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Creating an API Certificate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Encrypting Your Certificate Into PKCS12 Format . . . . . . . . . . . . . . . . . . . . 51 Importing Your Certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Chapter B PayPal Name-Value Pair API Basics . . . . . . . . . . . . . 55 PayPal API Client-Server Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4 August 7, 2012 Express Checkout Integration Guide Contents PayPal Name-Value Pair API Requests and Responses . . . . . . . . . . . . . . . . 56 UTF-8 Character Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Multiple API Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 NVP Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Creating an NVP Request . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Specifying the PayPal API Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Specifying an API Credential Using Signatures . . . . . . . . . . . . . . . . . . . . . 59 URL Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 List Syntax for Name-Value Pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Executing NVP API Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Specifying a PayPal Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Logging API Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Responding to an NVP Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Common Response Fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Error Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 URL Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Chapter C PayPal SOAP API Basics . . . . . . . . . . . . . . . . . . 65 PayPal WSDL/XSD Schema Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 PayPal SOAP API Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 SOAP RequesterCredentials: Username, Password, Signature, and Subject. . . . . . . . 67 SOAP Service Endpoints. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 SOAP Request Envelope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Request Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 SOAP Message Style: doc-literal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Response Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 Error Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 CorrelationID for Reporting Problems to PayPal. . . . . . . . . . . . . . . . . . . . . . . 75 UTF-8 Character Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Date/Time Formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Core Currency Amount Data Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Express Checkout Integration Guide August 7, 2012 5 Contents 6 August 7, 2012 Express Checkout Integration Guide Preface About This Guide This document describes basic Express Checkout integration. Intended Audience This document is for merchants and developers who want to get started implementing Express Checkout. Where to Go for More Information Express Checkout Advanced Features Guide Name-Value Pair API Developer Guide SOAP API Developer Reference Merchant Setup and Administration Guide Documentation Feedback Help us improve this guide by sending feedback to: documentationfeedback@paypal.com Express Checkout Integration Guide August 7, 2012 7 Preface Documentation Feedback 8 August 7, 2012 Express Checkout Integration Guide 1 Getting Started With Express Checkout The Express Checkout button gives buyers another way to pay, and it complements your existing payment solution. Online shoppers appreciate the convenience and security of PayPal, where they can pay with their PayPal balance, bank account, or credit card. Key Features of Express Checkout Express Checkout is a fast, easy way for buyers to pay with PayPal. Express Checkout eliminates one of the major causes of checkout abandonment by giving buyers all the transaction details at once, including order details, shipping options, insurance choices, and tax totals. Studies show that adding the Express Checkout button to your website can increase your sales up to 18 percent. The following web page shows the Express Checkout button side-by-side with an existing checkout button: Express Checkout Integration Guide August 7, 2012 9 Getting Started With Express Checkout Key Features of Express Checkout Use Express Checkout to: 10 Accept payments from any PayPal account. Eliminate the need for customers to enter personal information, including shipping, billing, or payment information. Keep customers on your site after completing the transaction. Sign up customers to make payments at regular intervals. August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Key Features of Express Checkout See more at: https://merchant.paypal.com/cgibin/marketingweb?cmd=_rendercontent&content_ID=merchant/express_checkout&nav=2.1.5 The Express Checkout Experience Express Checkout makes it easier for buyers to pay online. It also enables you to accept PayPal while retaining control of the buyer and the overall checkout flow. Consider your buyers’ experience before implementing Express Checkout. A generic flow probably has the following sequence of pages: A generic checkout flow In a typical checkout flow, a buyer: 1. Checks out from the shopping cart page 2. Provides shipping information 3. Chooses a payment option and provides billing and payment information 4. Reviews the order and pays 5. Receives an order confirmation In an Express Checkout flow, a buyer still checks out at the beginning of the flow. However, the buyer does not enter shipping, billing, or payment information, because PayPal provides the stored information. This simplifies and expedites the checkout process. The following diagram shows the Express Checkout flow: Express Checkout flow In the Express Checkout flow, the buyer: 1. Chooses Express Checkout by clicking Check out with PayPal 2. Logs into PayPal to authenticate his or her identity Express Checkout Integration Guide August 7, 2012 11 Getting Started With Express Checkout Relationship Between Express Checkout and Shopping Carts 3. Reviews the transaction on PayPal NOT E : Optionally, (not shown in the diagram), the buyer can then proceed to review the order on your site. You can also include other checkout steps, including upselling on your Review Order page. 4. Confirms the order and pays from your site 5. Receives an order confirmation Supported Countries and Currencies Express Checkout enables you to accept payments from many countries and regions. The checkout flow is also localized for a subset of countries. For information about the countries and currencies that Express Checkout supports, see PayPal Offerings Worldwide. For information about localized flows and additional country information, see Send and Receive Payments Securely Worldwide. Relationship Between Express Checkout and Shopping Carts If you do not have your own shopping cart and have not integrated Express Checkout with your website, you might consider using a third-party shopping cart. A shopping cart is software that lets buyers put items in a basket and calculates totals during checkout. PayPal partners with a wide variety of shopping carts, all of which are PayPal compatible and provide secure purchases for your buyers. The shopping cart vendor provides instructions for integrating their shopping cart on your website. See the PayPal Partner Directory (https://www.paypalmarketing.com/emarketing/partner/directory/directory.page?type=Shopp ing+Cart#mode=dir&dir%5Bops%5D=either&dir%5Bkey%5D=Keyword+term&dir% 5Btyp%5D%5B%5D=1&dir%5Bind%5D%5B%5D=0&dir%5Brod%5D%5B%5D=1&dir%5Brod %5D%5B%5D=2) for available shopping carts. IM PORT AN T : If you choose a shopping cart, do not contact PayPal. PayPal has no authority over a shopping cart vendor and cannot help you resolve issues that might arise from the integration with or use of a third-party shopping cart. Express Checkout Prerequisites Prerequisites to Express Checkout include the kind of PayPal accounts you need as well as the required programming skills and experience. If you want to use Express Checkout but do not have the required skills or experience, you should consider using PayPal Payments Standard (previously known as Website Payments Standard) or a shopping cart provided by PayPal or a third party. 12 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration To use Express Checkout, you must have: A Business or Premier account. A Business or Premier account enables you to become a merchant for whom PayPal collects money from buyers for goods or services. PayPal manages these transactions and charges you a small fee and a percentage of the amount collected from the buyer for each transaction. A Sandbox account with two test accounts. The PayPal Sandbox provides an environment that simulates PayPal, in which you execute your Express Checkout integration without actually exchanging money. One of your test accounts represents you as the merchant, or seller using Sandbox terminology, and the other test account represents a buyer. Your testing is not restricted to just two accounts; however, you must have a Sandbox account to create test accounts and perform actual testing. HTML experience. Probably, you already have an existing website and may have already implemented a checkout experience for the goods or services you sell on your site. You will need to add the Pay with Express Checkout button, as well as another button, called the Express Checkout mark, to your web pages. The Pay with Express Checkout button initiates the PayPal checkout flow. The mark enables the buyer to choose Express Checkout from the page that specifies the payment method, called the payment page, in case the buyer did not start with Pay with Express Checkout. Programming experience. When the buyer clicks a button, you must provide code that requests a PayPal server to set up or process the transaction and code to handle the response. PalPal provides an easy-to-user interface built on the HTTP request-response model, as well as a more complicated SOAP web services interface. PayPal also provides Software Development Kits (SDKs) that provide an interface in various programming languages, such as PHP, Ruby, Java, and .NET languages like C#. Although you need not know a specific language, you will need to understand programming logic, especially the request-response model, error handling, and the nuances of writing application-level code. NOT E : If the description of the programming experience prerequisite seems confusing (like “what’s an interface?”), you can still use Express Checkout provided by a shopping cart vendor, including PayPal, or use another PayPal product, such as PayPal Payments Standard. You should not attempt to integrate Express Checkout on your own unless you have sufficient programming experience. A programmer or developer will find Express Checkout easy; a complete novice could lose sales or goods and not even know it. Implementing the Simplest Express Checkout Integration The simplest Express Checkout integration requires you to set up a PayPal button and call the following PayPal API operations when your buyer clicks the button: SetExpressCheckout, DoExpressCheckoutPayment, and typically, GetExpressCheckoutDetails. You must also enable the buyer to select PayPal as the payment method after the buyer starts to check out. Thus, you must call these API operations from two places. You must perform these API operations on your checkout page and on your payment method page. Express Checkout Integration Guide August 7, 2012 13 Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration Related information: "Express Checkout Flow" on page 35 Obtaining an Express Checkout Button and PayPal Mark PayPal requires that you use the Check out with PayPal button and the PayPal mark image hosted on secure PayPal servers. When the images are updated, the changes appear automatically in your application. You must put the Express Checkout button on your checkout page. To obtain an Express Checkout Button: 1. Go to the PayPal Button Code page (https://www.paypal.com/express-checkout-buttons). A page similar to the following one appears: 2. Select and copy the image source text from the window below the button. 3. Paste the image source text into your checkout page’s HTML source where you want the button to appear on your page. Result: When you display your checkout page in the browser, the Check out with PayPal button should appear: 14 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration After Completing This Task: You will need to place the PayPal mark image on your payment page. The instructions for obtaining this image are similar to the instructions for obtaining the button. The mark is found on the same Button Code page (https://www.paypal.com/express-checkout-buttons) as the Express Checkout button: Before You Start Coding If you are not familiar with how PayPal APIs work, read this topic. It provides the minimum information you need to be successful using the PayPal Name-Value Pair API. PayPal API Client-Server Architecture The PayPal API uses a client-server model in which your website is a client of the PayPal server. A page on your website initiates an action on a PayPal API server by sending a request to the server. The PayPal server responds with a confirmation that the requested action was taken or indicates that an error occurred. The response might also contain additional information related to the request. The following diagram shows the basic request-response mechanism. Express Checkout Integration Guide August 7, 2012 15 Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration For example, you might want to obtain the buyer’s shipping address from PayPal. You can initiate a request specifying an API operation to obtain buyer details. The response from the PayPal API server contains information about whether the request was successful. If the operation succeeds, the response contains the requested information. In this case, the response contains the buyer’s shipping address. If the operation fails, the response contains one or more error messages. Related information: "Creating an NVP Request" on page 58 "Responding to an NVP Response" on page 62 Obtaining API Credentials To use the PayPal API, you must have API credentials that identify you as a PayPal Business or Premier account holder who is authorized to perform various API operations. Although you can use either an API signature or a certificate for credentials, PayPal recommends you use a signature. IM PORT AN T : Although you can have both a signature and certificate, you cannot use both at the same time. Setting Up the Express Checkout Transaction To set up an Express Checkout transaction, you must invoke the SetExpressCheckout API operation to provide sufficient information to initiate the payment flow and redirect to PayPal if the operation was successful. This example assumes that you have set up the mechanism you will use to communicate with the PayPal server and have a PayPal Business account with API credentials. It also assumes that the payment action is a final sale. When you set up an Express Checkout transaction, you specify values in the SetExpressCheckout request and then call the API. The values you specify control the PayPal page flow and the options available to you and your buyers. You should start by setting up a standard Express Checkout transaction, which can be modified to include additional options. To set up the simplest standard Express Checkout transaction: 16 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration 1. Specify that you want to execute the SetExpressCheckout API operation and the version you want to use. METHOD=SetExpressCheckout VERSION=XX.0 2. Specify your API credentials. Use the following parameters for a signature: USER=API_username PWD=API_password SIGNATURE=API_signature In the Sandbox, you can always use the following signature: USER=sdk-three_api1.sdk.com PWD=QFZCWN5HZM8VBG7Q SIGNATURE=A-IzJhZZjhg29XQ2qnhapuwxIDzyAZQ92FRP5dqBzVesOkzbdUONzmOU 3. Specify the amount of the transaction; include the currency if it is not in US dollars. Specify the total amount of the transaction if it is known; otherwise, specify the subtotal. Regardless of the specified currency, the format must have a decimal point with exactly two digits to the right and an optional thousands separator to the left, which must be a comma. For example, EUR 2.000,00 must be specified as 2000.00 or 2,000.00. The specified amount cannot exceed USD $10,000.00, regardless of the currency used. PAYMENTREQUEST_0_AMT=amount PAYMENTREQUEST_0_CURRENCYCODE=currencyID 4. Specify the return URL. The return URL is the page to which PayPal redirects your buyer’s browser after the buyer logs into PayPal and approves the payment. Typically, this is a secure page (https://...) on your site. NOT E : You can use the return URL to piggyback parameters between pages on your site. For example, you can set your Return URL to specify additional parameters using the https://www.yourcompany.com/page.html?param=value... syntax. The parameters become available as request parameters on the page specified by the Return URL. RETURNURL=return_url Express Checkout Integration Guide August 7, 2012 17 Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration 5. Specify the cancel URL. The cancel URL is the page to which PayPal redirects your buyer’s browser if the buyer does not approve the payment. Typically, this is the secure page (https://...) on your site from which you redirected the buyer to PayPal. NOT E : You can pass SetExpressCheckout request values as parameters in your URL to have the values available, if necessary, after PayPal redirects to your URL. CANCELURL=cancel_url 6. Specify the payment action. Although the default payment action is a Sale, it is a best practice to explicitly specify the payment action as one of the following values: PAYMENTREQUEST_0_PAYMENTACTION=Sale After Completing This Task: If calling the SetExpressCheckout API was successful, redirect the buyer’s browser to PayPal and execute the _express-checkout command using the token returned in the SetExpressCheckout response. NOT E : The following example uses the PayPal Sandbox server: https://www.sandbox.paypal.com/webscr ?cmd=_express-checkout&token=tokenValue Obtaining Express Checkout Transaction Details To obtain details about an Express Checkout transaction, you can invoke the GetExpressCheckoutDetails API operation. This example assumes that PayPal redirects to your buyer’s browser with a valid token after the buyer reviews the transaction on PayPal. Although you are not required to invoke the GetExpressCheckoutDetails API operation, most Express Checkout implementations take this action to obtain information about the buyer. You invoke the GetExpressCheckoutDetails API operation from the page specified by return URL, which you set in your call to the SetExpressCheckout API. Typically, you invoke this operation as soon as the redirect occurs and use the information in the response to populate your review page. To obtain a buyer’s shipping address and Payer ID: 1. Specify that you want to execute the GetExpressCheckoutDetails API operation and the version you want to use. 18 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration METHOD=GetExpressCheckoutDetails VERSION=XX.0 2. Specify your API credentials. Use the following parameters for a signature: USER=API_username PWD=API_password SIGNATURE=API_signature 3. Specify the token returned by PayPal when it redirects the buyer’s browser to your site. PayPal returns the token to use in the token HTTP request parameter when redirecting to the URL you specified in your call to the SetExpressCheckout API. TOKEN=tokenValue 4. Execute the GetExpressCheckoutDetails API to obtain information about the buyer. 5. Access the fields in the GetExpressCheckoutDetails API response. NOT E : Only populated fields are returned in the response. Completing the Express Checkout Transaction To complete an Express Checkout transaction, you must invoke the DoExpressCheckoutPayment API operation. This example assumes that PayPal redirects your buyer’s browser to your website with a valid token after you call the SetExpressCheckout API. Optionally, you may call the GetExpressCheckoutDetails API before calling the DoExpressCheckoutPayment API. In the simplest case, you set the total amount of the order when you call the SetExpressCheckout API. However, you can change the amount before calling the DoExpressCheckoutPayment API if you did not know the total amount when you called the SetExpressCheckout API. This example assumes the simplest case, in which the total amount was specified in the return URL when calling the SetExpressCheckout API. Although you can specify additional options, this example does not use any additional options. To execute an Express Checkout transaction: 1. Specify that you want to execute the DoExpressCheckoutPayment API operation and the version you want to use. Express Checkout Integration Guide August 7, 2012 19 Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration METHOD=DoExpressCheckoutPayment VERSION=XX.0 2. Specify your API credentials. Use the following parameters for a signature: USER=API_username PWD=API_password SIGNATURE=API_signature 3. Specify the token returned by PayPal when it redirects the buyer’s browser to your site. PayPal returns the token to use in the token HTTP request parameter when redirecting to the URL you specified in your call to the SetExpressCheckout API. TOKEN=tokenValue 4. Specify the Payer ID returned by PayPal when it redirects the buyer’s browser to your site. PayPal returns the Payer ID to use in the token HTTP request parameter when redirecting to the URL you specified in your call to the SetExpressCheckout API. Optionally, you can obtain the Payer ID by calling the GetExpressCheckoutDetails API. PAYERID=id 5. Specify the amount of the order including shipping, handling, and tax; include the currency if it is not in US dollars. Most of the time, this will be the same amount as you specified in your SetExpressCheckout call, adjusted for shipping and taxes. PAYMENTREQUEST_0_AMT=amount PAYMENTREQUEST_0_CURRENCYCODE=currencyID 6. Specify the same payment action that you specified in SetExpressCheckout. PAYMENTREQUEST_0_PAYMENTACTION=Sale Testing an Express Checkout Integration You can test your Express Checkout integration in the Sandbox. This example shows how to simulate your web pages using HTTP forms and supplying the values for API operations from these forms. You can use this strategy for your initial testing; however, for more complete testing, you need to replace these forms with your web pages containing your actual code. 20 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration The following diagram shows the Express Checkout execution flow, which uses the Sandbox as the API server. The pages on the left represent your site. The following steps match the circled numbers in the diagram. Perform the actions in each step to test Express Checkout. 1. Invoke a form on your site that calls the SetExpressCheckout API on the Sandbox. To invoke the API, set form fields whose names match the NVP names of the fields you want to set, specify their corresponding values, and then post the form to a PayPal Sandbox server, such as https://api-3t.sandbox.paypal.com/nvp, as shown in the following example: Express Checkout Integration Guide August 7, 2012 21 Getting Started With Express Checkout Implementing the Simplest Express Checkout IntegrationNOT E : Use an API username from a Sandbox business test account for which a signature exists. See the Test Certificates tab of the Sandbox to obtain a signature. If you are not using a signature, you must use a different Sandbox server. IM PORT AN T : This example does not establish a secure connection and should not be used live on paypal.com.You must protect the values for USER, PWD, and SIGNATURE in your implementation. Consider storing these values in a secure location other than your web server document root and setting the file permissions so that only the system user that executes your ecommerce application can access it. 2. Review the response string from the SetExpressCheckout API operation. PayPal responds with a message, such as the one shown below. Note the status, which should include ACK set to Success, and a token that is used in subsequent steps. TIMESTAMP=2007%2d04%2d05T23%3a23%3a07Z &CORRELATIONID=63cdac0b67b50 &ACK=Success &VERSION=XX%2e000000 &BUILD=1%2e0006 &TOKEN=EC%2d1NK66318YB717835M 3. If the operation was successful, use the token and redirect your browser to the Sandbox to log in, as follows: 22 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration https://www.sandbox.paypal.com/cgi-bin/webscr? cmd=_express-checkout &token=EC-1NK66318YB717835M You may need to decode the URL, which is the opposite of URL encoding, by replacing hexadecimal codes with ASCII codes; for example, you may need to replace %2d in the token with a hyphen ( - ). You must log in to https://developer.paypal.com before you log in to a Sandbox test account. You then log in to the test account that represents the buyer, not the seller’s business test account that represents you as the merchant. 4. After logging into the buyer test account, confirm the details. When you confirm, the Sandbox redirects your browser to the return URL you specified when invoking the SetExpressCheckout API operation, as in the following example: http://www.YourReturnURL.com/ ?token=EC-1NK66318YB717835M&PayerID=7AKUSARZ7SAT8 5. Invoke a form on your site that calls the GetExpressCheckoutDetails API operation on the Sandbox: If the operation was successful, the GetExpressCheckoutDetails API returns information about the payer, such as the following information: Express Checkout Integration Guide August 7, 2012 23 Getting Started With Express Checkout Implementing the Simplest Express Checkout Integration TIMESTAMP=2007%2d04%2d05T23%3a44%3a11Z &CORRELATIONID=6b174e9bac3b3 &ACK=Success &VERSION=XX%2e000000 &BUILD=1%2e0006 &TOKEN=EC%2d1NK66318YB717835M &EMAIL=YourSandboxBuyerAccountEmail &PAYERID=7AKUSARZ7SAT8 &PAYERSTATUS=verified &FIRSTNAME=... &LASTNAME=... &COUNTRYCODE=US &BUSINESS=... &PAYMENTREQUEST_0_SHIPTONAME=... &PAYMENTREQUEST_0_SHIPTOSTREET=... &PAYMENTREQUEST_0_SHIPTOCITY=... &PAYMENTREQUEST_0_SHIPTOSTATE=CA &PAYMENTREQUEST_0_SHIPTOCOUNTRYCODE=US &PAYMENTREQUEST_0_SHIPTOCOUNTRYNAME=United%20States &PAYMENTREQUEST_0_SHIPTOZIP=94666 &PAYMENTREQUEST_0_ADDRESSID=... &PAYMENTREQUEST_0_ADDRESSSTATUS=Confirmed 6. Invoke a form on your site that invokes the DoExpressCheckoutPayment API operation on the Sandbox: 24 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Troubleshooting Your Express Checkout Integration 7. Review the response string from the DoExpressCheckoutPayment API operation. If the operation was successful, the response should include ACK set to Success, as follows: TIMESTAMP=2007%2d04%2d05T23%3a30%3a16Z &CORRELATIONID=333fb808bb23 ACK=Success &VERSION=XX%2e000000 &BUILD=1%2e0006 &TOKEN=EC%2d1NK66318YB717835M &PAYMENTREQUEST_0_TRANSACTIONID=043144440L487742J &PAYMENTREQUEST_0_TRANSACTIONTYPE=expresscheckout &PAYMENTREQUEST_0_PAYMENTTYPE=instant &PAYMENTREQUEST_0_ORDERTIME=2007%2d04%2d05T23%3a30%3a14Z &PAYMENTREQUEST_0_AMT=19%2e95 &PAYMENTREQUEST_0_CURRENCYCODE=USD &PAYMENTREQUEST_0_TAXAMT=0%2e00 &PAYMENTREQUEST_0_PAYMENTSTATUS=Pending &PAYMENTREQUEST_0_PENDINGREASON=authorization &PAYMENTREQUEST_0_REASONCODE=None Security Issues You must always be concerned with protecting sensitive data. This not only includes your API credentials, but also any data exposed in a client’s browser, such as data about the transaction stored in cookies. In the simplest examples, such as the ones provided by PayPal to demonstrate Express Checkout usage, the API credentials may be exposed. Thus, if you copy code from examples or SDKs, you should always review your website for security issues and correct them before you go live with your website. Encrypt all saved information related to the PayPal transaction. For example, if you keep order status information in a cookie, make sure the information is encrypted. Use a secure transmission protocol, such as HTTPS to transfer information between your site and PayPal. Do not use HTTP or insecure cURL. Troubleshooting Your Express Checkout Integration If you have trouble with your integration, there are several things you can check first. If you try them yet continue to have problems, you can also contact Merchant Technical Support (MTS). If you cannot resolve the issue yourself, you will need to gather some basic information before contacting MTS, including a log of the actions that led to the error. You can contact MTS at https://www.paypal.com/mts. Express Checkout Integration Guide August 7, 2012 25 Getting Started With Express Checkout Troubleshooting Your Express Checkout Integration Error Handling The response message contains an ACK value. Unless ACK=Success, you must check further for an error or warning message. You must check each response from the PayPal server for an indication that an error occurred. Because there are several warning and failure values, the safest way to check the response is to check for ACK=Success. If the ACK returns any other value, you must examine the response for error numbers and messages. A non-successful response can contain more than one error number and message. Error fields start with L_ERRORCODEn, where n, starting from 0, identifies a unique error in the response. There are two messages for each error number, L_SHORTMESSAGEn and L_LONGMESSAGEn, where n corresponds with n in L_ERRORCODEn. IM PORT AN T : Because error numbers are not guaranteed to be unique, you must use both the number and the messages to determine the appropriate action to take when an error occurs. Some errors are transitory in nature and you can retry the operation; for example, an error that indicates a problem with PayPal. If the problem persists for more than an hour, it is probably related to your Express Checkout implementation because PayPal servers are up and running almost all of the time. Some errors indicate problems with the buyer’s account; for example, the funding source is no longer valid or the buyer’s account is restricted in some way. The error message has enough information to create a message on your website that tells the buyer how to resolve the issue. Often, you simply prompt the buyer to choose a different funding source. Because these kinds of problems can indicate a risk issue, you do not want to ship goods until the issue has been resolved. Other errors indicate a problem with your integration, such as accepting invalid input on your website and passing it in your request message to PayPal. You need to perform sufficient testing using the Sandbox to prevent problems from arising after going live. Timeouts A timeout situation occurs if an API operation’s completion status is not known or the buyer navigates away from the page that receives the response before PayPal completes the operation. You must not ship goods before receiving a valid transaction ID, which indicates that PayPal accepted the payment. It is safe to execute the API operation again if the status is not known. In the case of DoExpressCheckout, you can execute GetExpressCheckoutDetails and examine the CheckoutStatus field. Any value other than PaymentCompleted indicates that the payment has not completed. You should not ship goods until you receive a valid transaction ID from calling either DoExpressCheckoutPayment or GetExpressCheckoutDetails. 26 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Express Checkout Features Logging API Operations You should log basic information from the request and response messages of each PayPal API operation you execute. You must log the Correlation ID from the response message, which identifies the API operation to PayPal and which must be provided to Merchant Technical Support if you need their assistance with a specific transaction. All responses to PayPal API operations contain information that may be useful for debugging purposes. In addition to logging the Correlation ID from the response message, you can log other information, such as the transaction ID and timestamp, to enable you to review a transaction on the PayPal website or through the API. You could implement a scheme that logs the entire request and response in a “verbose” mode; however, you should never log the password from a request. Encoding and Decoding Values You must encode and decode all values sent in API operations. Only encode the value and not the name in NVP and not the tags in SOAP. You must encode all request field values in a request to PayPal and decode all field values in the response. You must encode and decode individual values; do not encode or decode the entire message. Browsers often attempt to encode and decode messages that are redirected to or from them; however, you must verify that encoding and decoding is done correctly and only to field values. Express Checkout Features Express Checkout features include ways to configure Express Checkout API reqeusts, ways to customize the PayPal checkout pages, and additional settings you can specify. Customizing the Express Checkout User Interface You can customize the appearance of the PayPal Express Checkout pages. Some changes alter the checkout flow. Express Checkout includes options for presenting the checkout pages that appear when the buyer logs into PayPal during checkout. Some of them make the PayPal pages look like your own pages, giving the customer a consistent visual presentation: Logo to display Colors for the background and border Language in which PayPal content is displayed Your customer service number Express Checkout Integration Guide August 7, 2012 27 Getting Started With Express Checkout Express Checkout Features NOT E : All of the above customizations can be set in your profile. You set them in an Expresss Checkout API operation only when you want to override the default provided by your profile. Other options streamline the flow, by allowing the buyer to complete the payment on PayPal, or change the kind of information that is presented during checkout. On the PayPal Review page, you can: Include per-item details Include tax, insurance, shipping costs, and shipping discounts Indicate whether the total displayed on the page is exact or an estimate before items such as tax and shipping costs Display a note to the buyer; for example, a note identifying the shipping options are available Allow your buyer to specify instructions to you Assign an invoice number to a payment Other features may be used in specialized cases: Shipping address display and usage Choices for gift wrapping Buyer consent to receive your promotional materials Survey questions Settlements and Captured Payments Express Checkout enables you to collect a payment immediately or capture the payment later; for example, when you ship the goods. Express Checkout provides several ways to set up a transaction for later capture. Often, you accept a payment and ship goods immediately, which is referred to as a sale. In addition to immediate payments, Express Checkout allows you to authorize payments to be captured later, which is referred to as an authorization. An authorization is useful, for example, when you want to reserve a buyer’s funds pending the shipment of goods; the actual payment is captured when the goods are shipped. An authorization can be reauthorized one time if necessary; for example, when you are unable to ship within 3 days of the authorization. Express Checkout provides an additional option, called an order, which you use when a single authorization is insufficient. You can create multiple authorizations and capture them as part of the same order. This is useful, for example, when an order is split into multiple shipments and you need to capture a payment each time part of the order is shipped. Refunds You can issue full or partial refunds up to the full amount of the payment. You can make a refund for payments captured initially or as part of a later settlement. 28 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Express Checkout Features You cannot make a refund if the transaction occurred after the refund period has passed, which typically is 60 days. Related information: "Issuing Refunds" on page 41 Recurring Payments Express Checkout provides recurring payments, which enables you to manage subscriptions and other payments on a fixed schedule. If you have permission from PayPal to use reference transactions, you can provide variable payments on a varying schedule. When you support recurring payments for a buyer, you create a recurring payments profile. The profile contains information about the recurring payments, including details for an optional trial period and a regular payment period. Both periods contain information about the payment frequency and payment amounts, including shipping and tax, if applicable. After creating a profile, PayPal automatically queues payments based on the billing start date, billing frequency, and billing amount. Payments reoccur until the profile expires, there are too many failed payments to continue, or you cancel the profile. Permission to allow recurring payments is established by the buyer setting up a billing agreement with the merchant on PayPal. For Express Checkout, the billing agreement can be established either in advance or when the buyer first makes a purchase; in either case, it occurs when you call Express Checkout API operations. Recurring Payments Using Reference Transactions Recurring payments using reference transactions is an alternative, which enables you to handle payments for varying amounts of money on a varying schedule. A reference transaction is a financial transaction from which subsequent transactions can be derived; for example, a buyer can make a purchase on your site and the PayPal transaction ID, called a reference transaction ID, can later be used to initiate another transaction. Mobile Express Checkout PayPal supports several implementations of Mobile Express Checkout. You can provide a complete mobile website, or you can create a mobile phone app in which the checkout button is integrated into the app itself or is on your mobile website. On mobile devices, Express Checkout provides payment pages tailored for faster checkout and for smaller mobile screens and keyboards. You can either set up the experience so that the buyer pays on your site or pays on PayPal. Parallel Payments With Express Checkout Parallel payments enable buyers to pay multiple merchants in an Express Checkout flow. This feature is not available for Mobile Express Checkout. Express Checkout Integration Guide August 7, 2012 29 Getting Started With Express Checkout Express Checkout Features In parallel payments, a merchant acts as marketplace host. Consider an online travel agency. The buyer purchases airline tickets and makes reservations from various merchants such as hotels, car rental agencies, and entertainment venues hosted on the site. By implementing parallel payments through Express Checkout, the marketplace host accepts PayPal as a payment method. The host also provides the buyer with a consolidated order on the PayPal Review page, summarizing expenses, itineraries, and other supporting information. Buyers see travel information, including cancellation fees, directly from the supplier on the Transaction Details page and in an email message. Fraud Management Filters Fraud Management Filters (FMF) provide you filters that identify potentially fraudulent transactions. There are 2 categories of filters: Basic filters screen against data such as the country of origin and the value of transactions. PayPal provides basic filters for Business accounts and Website Payments Pro accounts. Advanced filters screen data such as credit card and addresses information, lists of highrisk indicators, and additional transaction characteristics. Website Payments Pro merchants can upgrade to use these filters. NOT E : Using advanced filters might incur additional charges. For more information about Fraud Management Filters, see Fraud Management Filters Event Notification In most cases, you can use PayPal API operations to determine the information you need about a transaction. However, there may be some cases in which you must set up IPN; for example, when you need automatic notification about actions, such as disputes and their resolution. IPN is a message service that PayPal uses to notify you about events, such as: Instant payments, including Express Checkout, Adaptive Payments, and direct credit card payments, and authorizations, which indicate a sale whose payment has not yet been collected eCheck payments and associated status, such as pending, completed, or denied, and payments pending for other reasons, such as those being reviewed for potential fraud Recurring payment and subscription actions Chargebacks, disputes, reversals, and refunds associated with a transaction For more information about IPN, see Instant Payment Notification Guide 30 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Express Checkout Building Blocks Dynamic Images Overview Dynamic images enables PayPal to tailor the Express Checkout button for a campaign or event. This feature is not supported for Mobile Express Checkout. When you participate in a PayPal campaign or event, PayPal automatically updates the image to reflect the campaign information. When the campaign is over, PayPal restores the default image. You are not responsible for scheduling or making changes to your website application code before, during, or after the campaign. These activities are all handled for you when you set up the dynamic image. Express Checkout Instant Update The instant update feature enables you to create a message that responds with shipping information, allowing you to provide location-based shipping, insurance, and tax information. It is not available for Mobile Express Checkout. You specify a URL that provides the information, which is based on the buyer’s address which is stored on PayPal. You are not allowed to see the buyer’s actual address. Express Checkout Building Blocks You implement Express Checkout flows with Express Checkout buttons, PayPal API operations, PayPal commands, and tokens. The following conceptual diagram identifies the building blocks that you use to integrate Express Checkout on your website: Express Checkout Integration Guide August 7, 2012 31 Getting Started With Express Checkout Express Checkout Building Blocks Express Checkout Integration A token is a value assigned by PayPal that associates the execution of API operations and commands with a specific instance of a user experience flow. NOT E : Tokens are not shown in the diagram. Express Checkout Buttons PayPal provides buttons and images for you to place on your website. To implement the Express Checkout shopping cart experience, place the following button on your Shopping Cart page: To implement PayPal as a payment option, which is part of the Express Checkout experience, associate the PayPal mark image with your payment options. PayPal recommends using radio buttons for payment options: 32 August 7, 2012 Express Checkout Integration Guide Getting Started With Express Checkout Express Checkout Building Blocks Express Checkout API Operations The PayPal API provides three API operations for Express Checkout. These API operations set up the transaction, obtain information about the buyer, and handle the payment and completes the transaction. API Operation Description SetExpressCheckout Sets up the Express Checkout transaction. You can specify information to customize the look and feel of the PayPal site and the information it displays. You must include the following information: URL to the page on your website that PayPal redirects to after the buyer logs into PayPal and approves the payment successfully. URL to the page on your website that PayPal redirects to if the buyer cancels. Total amount of the order or your best estimate of the total. It should be as accurate as possible. GetExpressCheckout Obtains information about the buyer from PayPal, including shipping information. DoExpressCheckoutPayment Completes the Express Checkout transaction, including the actual total amount of the order. Express Checkout Command PayPal provides a command that you use when redirecting your buyer’s browser to PayPal. This command enables your buyer to log in to PayPal to approve an Express Checkout payment. When you redirect your buyer’s browser to PayPal, you must specify the _ExpressCheckout command for Express Checkout. You also specify the token that identifies the transaction, which was returned by the SetExpressCheckout API operation. NOT E : To enable PayPal to redirect back to your website, you must have already invoked the SetExpressCheckout API operation, specifying URLs that PayPal uses to redirect back to your site. PayPal redirects to the success URL when the buyer pays on PayPal; otherwise, PayPal redirects to the cancel URL. If the buyer approves the payment, PayPal redirects to the success URL with the following information: The token that was included in the redirect to PayPal The buyer’s unique identifier (Payer ID) If the buyer cancels, PayPal redirects to the cancel URL with the token that was included in the redirect to PayPal. Express Checkout Integration Guide August 7, 2012 33 Getting Started With Express Checkout Express Checkout Building Blocks Express Checkout Token Usage Express Checkout uses a token to control access to PayPal and execute Express Checkout API operations. The SetExpressCheckout API operation returns a token, which is used by other Express Checkout API operations and by the _ExpressCheckout command to identify the transaction. The life of the token is approximately 3 hours. 34 August 7, 2012 Express Checkout Integration Guide 2 Express Checkout User Interface Requirements Your Express Checkout integration must conform to PayPal’s requirements for button use and placement. You must use only buttons hosted on PayPal and place them on your checkout and payment pages. Express Checkout Flow To implement Express Checkout, you must offer it both as a checkout option and as a payment method. Typically, you initiate the Express Checkout flow on your shopping cart page and on your payment options page. You add Express Checkout to your existing flow by placing the Checkout with PayPal button on your Shopping Cart page and by placing the PayPal mark on your Payment Methods page. The following diagram shows the complete flow: Complete Express Checkout flow Make the following changes to implement the complete Express Checkout flow: On your Shopping Cart page, place the Checkout with PayPal button. Handle clicks by sending the Express Checkout setup request. After receiving the response, redirect your buyer’s browser to PayPal. On your Payment Methods page, associate the PayPal mark with an option. Handle clicks by sending the Express Checkout setup request. After receiving the response, redirect your buyer’s browser to PayPal. On the page your buyer returns to, obtain shipping information from PayPal and accept the payment to complete the Express Checkout transaction. Express Checkout Integration Guide August 7, 2012 35 Express Checkout User Interface Requirements Express Checkout Flow NOT E : You also can allow the buyer to pay on the PayPal Review page. In this case, your checkout flow can omit the Merchant Review page and proceed directly to your Confirmation page. Related information: "Implementing the Simplest Express Checkout Integration" on page 13 Checkout Entry Point The checkout entry point is one of the places where you must implement Express Checkout. Buyers initiate the Express Checkout flow on your shopping cart page by clicking the Checkout with PayPal button. The following diagram shows how Express Checkout integrates with a typical checkout flow: Payment Option Entry Point The payment option entry point is one of the places where you must implement Express Checkout. Buyers initiate the Express Checkout flow on your payment methods page by selecting PayPal as the default option. The following diagram shows how to integrate Express Checkout from your payment methods page: 36 August 7, 2012 Express Checkout Integration Guide Express Checkout User Interface Requirements PayPal Button and Logo Images PayPal Button and Logo Images To inform buyers that PayPal is accepted on your website, you must place PayPal button and logo images in your checkout flow. PayPal recommends that you use dynamic images. PayPal requires that you use Check out with PayPal buttons and PayPal mark images hosted on secure PayPal servers. When the images are updated, the changes appear automatically in your application. Do not host copies of the PayPal images locally on your servers. Outdated PayPal buttons and images reduce buyer confidence in your site. Express Checkout Image Flavors The Check out with PayPal button and the PayPal mark image are available in two flavors: Dynamic image Static image The dynamic images enable PayPal to change their appearance dynamically. If, for example, you have signed up to participate in a PayPal campaign, PayPal can change the appearance of the image dynamically for the duration of that campaign based on parameter information you append to the image URL. The static images cannot be changed dynamically. To participate in a PayPal campaign, you would have to manually update the image code to change the image displayed and restore the default image when the campaign is over. The only way you can have image management taken care of for you is to replace static images in your implementation with dynamic images. Express Checkout Images The Check out with PayPal button is the image you place on your shopping cart page. The US version of the image looks like this. Express Checkout Integration Guide August 7, 2012 37 Express Checkout User Interface Requirements PayPal Button and Logo Images To create an Express Checkout button, see https://www.paypal.com/us/cgibin/webscr?cmd=xpt/Merchant/merchant/ExpressCheckoutButtonCode-outside. PayPal also provides buttons for other countries. To locate a page for another country, replace the country abbreviation in the link with another country abbreviation. For example, replace us with uk for United Kingdom, as follows: https://www.paypal.com/uk/cgibin/webscr?cmd=xpt/Merchant/merchant/ExpressCheckoutButtonCode-outside. PayPal hosts images for the countries: Country-specific buttons and images Country URL Change Country URL Change Country URL Change Country URL Change Australia au Austria at Belgium be Canada ca China cn France fr Germany de Italy it Japan j1 Netherlands nl Poland pl Spain es Switzerland ch United Kingdom uk United States us NOT E : URL changes are case sensitive. The abbreviation in the URL may not be a country code. Payment Mark The PayPal mark is the image you place on your payment methods page. It looks like this: To implement PayPal as a payment option, which is part of the Express Checkout experience, associate the PayPal mark image with your payment options. PayPal recommends using radio buttons for payment options: To create a PayPal mark, see https://www.paypal.com/cgibin/webscr?cmd=xpt/Marketing/general/OnlineLogoCenter-outside. 38 August 7, 2012 Express Checkout Integration Guide 3 Related API Operations When you create the simplest Express Checkout integration, you specify Sale as the payment action, enabling you to receive the money right away. You can also set up a payment to be collected later, or refund a payment. Sale Payment Action for Express Checkout A sale payment action represents a single payment that completes a purchase for a specified amount. A sale is the default Express Checkout payment action; however, you can also specify the following action in your SetExpressCheckout and DoExpressCheckoutPayment requests: PAYMENTREQUEST_n_PAYMENTACTION=Sale A sale is the most straightforward payment action. Choose this payment action if the transaction, including shipping of goods, can be completed immediately. To use this payment action: The final amount of the payment must be known when you invoke the DoExpressCheckoutPayment API operation You should intend to fulfill the order immediately, such as would be the case for digital goods or for items you have in stock for immediate shipment After you execute the DoExpressCheckoutPayment API operation, the payment is complete and further action is unnecessary. You cannot capture a further payment or void any part of the payment when you use this payment action. Authorization Payment Action for Express Checkout An authorization payment action represents an agreement to pay and places the buyer’s funds on hold for up to three days. To set up an authorization, specify the following payment action in your SetExpressCheckout and DoExpressCheckoutPayment requests: PAYMENTREQUEST_n_PAYMENTACTION=Authorization Express Checkout Integration Guide August 7, 2012 39 Related API Operations Order Payment Action for Express Checkout An authorization enables you to capture multiple payments up to 115% of, or USD $75 more than, the amount you specify in the DoExpressCheckoutPayment request. Choose this payment action if you need to ship the goods before capturing the payment or if there is some reason not to accept the payment immediately. The honor period, for which funds can be held, is three days. The valid period, for which the authorization is valid, is 29 days. You can reauthorize the 3-day honor period at most once within the 29-day valid period. You can void an authorization, in which case the uncaptured part of the amount specified in the DoExpressCheckoutPayment request becomes void and can no longer be captured. If no part of the payment has been captured, the entire payment becomes void and nothing can be captured. API operations associated with Authorization payment action in Express Checkout API Operation Description DoCapture Capture an authorized payment. DoReauthorization Reauthorize a payment. DoVoid Void an order or an authorization. Order Payment Action for Express Checkout An order payment action represents an agreement to pay one or more authorized amounts up to the specified total over a maximum of 29 days. To set up an order, specify the following payment action in your SetExpressCheckout and DoExpressCheckoutPayment requests: PAYMENTREQUEST_n_PAYMENTACTION=Order An order enables you to create multiple authorizations over the 29 days; each authorization you create places the buyer’s funds on hold for up to three days. You can capture multiple payments for each authorization, up to 115% of, or USD $75 more than, the amount you specify in the DoExpressCheckoutPayment request. NOT E : The default number of child authorizations in your PayPal account is 1. To do multiple authorizations please contact PayPal to request an increase. This payment action provides the most flexibility and should be used when either a sale does not meet, or one authorization plus one reauthorization, do not meet your needs. Situations in which orders are appropriate include the handling of: 40 Back orders, in which available merchandise is sent immediately and the remaining merchandise is sent when available, which may include more than two shipments Split orders, in which merchandise is sent in more than one shipment, perhaps to different addresses, and you want to collect a payment for each shipment August 7, 2012 Express Checkout Integration Guide Related API Operations Issuing Refunds Drop shipments, which are shipments from other vendors for which you accept the payment You cannot reauthorize an authorization. You handle the need to reauthorize, for example when the hold period or valid period of an authorization expires, simply by creating another authorization. You can void an order or an authorization created from the order. If you void an order, the uncaptured part of the amount specified in the DoExpressCheckoutPayment request becomes void and can no longer be captured. If no part of the payment has been captured, the entire payment becomes void and nothing can be captured. If you void an authorization associated with the order, the uncaptured part of the amount specified in the authorization becomes void and can no longer be captured. If no part of the authorization has been captured, the entire authorized payment becomes void. API operations associated with Order payment action in Express Checkout API Operation Description DoAuthorization Authorize a payment. DoCapture Capture an authorized payment. DoVoid Void an order or an authorization. Issuing Refunds You can use the RefundTransaction PayPal API operation to issue refunds. Use the RefundTransaction API to issue one or more refunds associated with a transaction, such as a transaction created by a capture of a payment. The transaction is identified by a transaction ID that PayPal assigns when the payment is captured. NOT E : You cannot make a refund if the transaction occurred after the refund period has passed; typically, the refund period is 60 days. You can refund amounts up to the total amount of the original transaction. If you specify a full refund, the entire amount is refunded. If you specify a partial refund, you must specify the amount to refund, the currency, and a description of the refund, which is called a memo. When you call the RefundTransaction API, PayPal responds with another transaction ID, which is associated with the refund (not the original transaction), and additional information about the refund. This information identifies: The gross amount of the refund, which is returned to the payer The amount of the refund associated with the original transaction fee, which is returned to you The net amount of the refund, which is deducted from your balance To issue a refund: Express Checkout Integration Guide August 7, 2012 41 Related API Operations Tracking Failed or Pending Requests 1. In the RefundTransaction request, specify the transaction ID of the transaction whose payment you want to refund. TRANSACTIONID=transaction_id 2. Specify the kind of refund, which is either Full or Partial. REFUNDTYPE=Full or REFUNDTYPE=Partial 3. For a partial refund, specify the refund amount, including the currency. AMT=amount CURRENCYCODE=currencyID 4. For a partial refund, specify the memo description. NOTE=description 5. Execute the RefundTransaction operation. 6. Check the acknowledgement status in the RefundTransaction response to ensure that the operation was successful. Related information: "Refunds" on page 28 Tracking Failed or Pending Requests You can use the MsgSubID (Message Submission ID) to help track pending or failed requests. MsgSubID has been added to the request and response for following API calls: DoAuthorization DoReferenceTransaction RefundTransaction DoCapture Idempotency is useful in cases where a request has failed or if you are unsure about the results of an original request. It also helps to correlate request payloads with response payloads. Idempotency helps to eliminate duplicate requests, since a request sent with a previously accompanying MsgSubID will return with latest status of of the previous request that used the 42 August 7, 2012 Express Checkout Integration Guide Related API Operations Tracking Failed or Pending Requests same MsgSubID. In contrast, a request with no accompanying MsgSubID will instead duplicate the request. Scenarios in which idempotency come into play: In an API request sent with a MsgSubID times out, a client application can retry the original request using the accompanying MsgSubID. If the request has finished processing, PayPal then provides the latest status of the request and might return a 11607 warning code (Duplicate request for specified Message Submission ID). If a client application sends two API requests with same MsgSubID at the same time, PayPal processes the first request and the other may fail with 11604 error code (Request for Message Submission ID already in progress). NOT E : For DoExpressCheckoutPayment, you can use the token in place of the MsgSubID. For mutliple payments, a combination of the token and PaymentRequestID should be used in place of the MsgSubID. The following example shows MsgSubID used as part of a DoAuthorization request:
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