This eBook will guide you through the steps necessary to add IAP to your Android app. Together, we will implement, from scratch, an Android application that uses the Amazon In-App Purchase APIs to allow in-app purchase of a magazine subscription.

In-App Purchasing (IAP) is gaining in popularity with developers as it continues to be a reliable revenue generator for mobile apps and games. It is the basis of Free-to-Play, eliminating up-front costs but allowing customers to purchase upgrades and add-ons they find valuable. The Amazon Appstore platform is designed to manage these transactions, and we have enhanced our In-App purchasing API to make it easier for you to manage the purchases your customers make.

Improved Customer Experience

With this update, the In-App Purchasing API improves the receipt process to provide better visibility into the fulfillment status of your customers’ in-app purchases.

The updated API replaces PurchaseToken with a unique receipt identifier called ReceiptId. The ReceiptId value allows you to:

• Determine fulfillment status and reconcile transaction records with your Amazon earnings report.
• Identify duplicate transactions to prevent over-fulfillment of digital content.
• Receive notification of transactions that cancel orders.

Getting Started

The updated API is backward-compatible, which means that your existing applications will continue to work without modification. We recommend that you migrate to the latest version, though, so that you can benefit from these improvements.

• If you are adding in-app purchasing to your app for the first time, simply build your project with the Amazon Mobile App SDK, which includes the latest version of the In-App Purchasing API.
• If your app already uses an older version of the API but you’re not ready to migrate from PurchaseToken to ReceiptId, you can still update to the latest version. Your app will work without modification, so you can prepare for the switch and follow through with the actual migration when you’re ready.
• If you are ready to use ReceiptId now, simply follow the migration guide available on our Developer Portal.

Additional Resources

For more details on in-app purchasing and how to implement it in your mobile projects, check out our Developer Portal and blog. Dive deep on the new API, or explore related topics such as increasing conversion, digital item sales in desktop and web-based applications, and managing promotions and discounts.

Big Blue Bubble is a Canadian development studio out of Ontario.  In the last few years, they have focused on creating free-to-play games for iOS, Android, including Kindle Fire, and Windows Phone. Their latest update to their app My Singing Monsters includes catchy new tunes from Grammy winner Kristian Bush and is not only a big hit with customers, but a big hit on the Amazon Appstore. Director of Development Bryan Davis shares some general strategy and how they generated 10%-15% better average revenue per user and 25%-30% better IAP revenue in the Amazon Appstore.

In-app purchasing: Big Blue Bubble goes for volume

Davis tells us: “A very important aspect of monetization from free-to-play games is IAP (in-app purchasing). Our strategy is to go for volume, rather than chasing whales.”  While average revenue per user (ARPU) is important, Bryan tells us that a high conversion rate is more important for Big Blue Bubble.

Big Blue Bubble games also use aggressive discounts to be successful.

“Something always needs to be ‘on sale’,” says Bryan. “People like to get discounts, so constantly running the promotions is the way to go.” Bryan recommends letting the promotions run for at least 3-4 days so the majority of your players have a chance to get a discount when they use the app.  

Better ARPU and IAP revenue than other stores

How is this working for Big Blue Bubble? We asked Bryan how well this strategy monetizes on the Amazon Appstore. He stated that: “…the overall revenues per user are just about 10-15% better.” However, “In terms of IAP, Amazon Appstore constantly outperforms other stores by 25%-30%.” 

Pre-Authorized Amazon Customers a Big Help to ARPU

Were there any special tricks or tips Big Blue Bubble used to get IAP to monetize so well on the Amazon Appstore? Bryan noted that: “…the fact that most users already have a credit card on file helps a lot.”

We also asked about downloads, and Bryan said that:

“In terms of download units, Amazon Appstore is still behind Google Play or iTunes App Store. In the Amazon Appstore ARPU is better and customer engagement is about the same.  The Amazon Appstore conversion rate from downloads to installs) is by far the highest and percentage of users with technical issues is the lowest.”

So is it safe to say Big Blue Bubble is happy with their app performance on the Amazon Appstore? “We are very happy with the performance. It is obvious that the user base is growing every day, not only for our game but for the Amazon Appstore as well.”

It’s good to hear that Big Blue Bubble’s monetization strategy is working well on the Amazon Appstore. We asked for any last recommendations, and Bryan had this to say: “Don’t keep [your customers] waiting too long for new content. Keep engaged with your audience at all time.”  We couldn’t agree more.

Learn more about the tools used by Big Blue Bubble:

Amazon Appstore Developer Console

Developer Promotions

Mobile Ads

Over six weeks after launching the Amazon In-App Purchasing API for general availability, we connected with Jeff Spears, VP of Marketing & Sales, and Sean Thompson, VP of Production, Mobile Deluxe, to chat about their company’s experience with IAP on Amazon. Headquartered in Santa Monica, Calif., Mobile Deluxe is an innovator and publisher of social mobile apps and provides free-to-play casual games that emphasize premium quality and fun game play. Mobile Deluxe titles include Big Win Slots, Solitaire Deluxe, and Big Win Blackjack. 

What motivated Mobile Deluxe to integrate with Amazon’s In-App Purchasing solution?

"Mobile Deluxe is bullish on Amazon’s foray into the app space given its expertise in merchandising, coupled with the ease of 1-Click purchase. As an organization, we made the shift from pay-to-download to free-to-play in April 2010, and our free revenues eclipsed paid revenues by July of 2011. As an industry, freemium revenues are forecasted to reach $5B in 2016, driven by smart phone adoption and user comfort with the IAP model. As a publisher we like  the freemium model since it eliminates the barrier of entry into our game, and it allows players to enjoy our products regardless of their style of play. You can either “earn” currency through game play, or purchase currency at your discretion to accelerate your game as you see fit. While we support both styles of play, from a business perspective we aren’t capping potential earnings in the latter example."

What is your monetization strategy?

"Big Win Slots monetizes through IAP, whereas Solitaire Deluxe and Big Win Blackjack use a hybrid monetization model that uses IAP and Ads. For Solitaire Deluxe, the majority of our revenue is derived from advertising, allowing our customers to play for free, unlimited. This has led to outstanding engagement and retention, and our average play time for users is in excess of 30 minutes. For Big Win Slots and Big Win Blackjack, we felt the natural progression of currency in casino apps made great sense. IAP allows us better control over our revenue stream versus fluctuating advertising CPM’s in an ad-based product, and it allows for flexibility in merchandising opportunities such as in-game sales events."

How has your experience with Amazon’s IAP solution compared to that on other platforms?

"When making an apples-to-apples comparison in May to competitive app stores, Amazon is our #1 monetizing channel in terms of $/DAU. I’m sure you’re aware of the Flurry release stating “revenue from Amazon’s Appstore is now at 89% of iTunes App Store revenue” here. We find that our Amazon $ per Daily Active User exceeds the average on other top storefronts where our apps are distributed by 87%. This speaks to the frictionless 1-Click option and Amazon’s merchandising prowess which drove “Big Win Slots” to the #1 spot in the “Casino” category."

How did you find integrating the Amazon SDK and IAP API?

 "Integration was exactly what we expected. We started from a baseline of already having integrated Google Checkout, so it was very easy to extend our existing functionality to include Amazon IAP. Amazon’s online resources were excellent. The “In-App Purchasing for Users of Google Billing” document was the perfect guide to help us get Amazon IAP integrated quickly. The API Reference was also helpful. Without question, this has been an ROI-positive experience for us. The total integration cost was about what we make in one day with Big Win Slots now."

Are there any tips you have to help other developers smoothly integrate the SDK?

"We recommend developers be forward looking when integrating any billing SDK. If at all possible, create an abstracted billing interface layer between your app(s) and the billing SDK. That will allow you to implement additional billing SDKs without having to make changes deep inside your project code. That means it is an easy tweak to add both Google and Amazon IAP solutions."

Michael Ritter, Vice President Licensing & Distribution at Social Gaming Network, is our guest blogger for this post.  SGN connects people around the world through great games, including Skies of Glory, Fluff Friend Rescue, Warp Rush, Bird's the Word, and Night of the Living Dead Defense.

We decided to participate in the Amazon Appstore In-App Purchasing beta program because Amazon is a ubiquitous and trusted ecommerce platform with disruptive devices, so we felt it was a perfect storm of opportunity.   Amazon's in-app purchasing solution created a great way for us to reduce friction and drive more revenue from our games, as tens of millions of people already have made purchases with Amazon.  Specifically, the Kindle Fire’s integrated storefront and marketplace work seamlessly and help drive mobile game distribution.  Through in-app purchases we are able to add additional content to our games, which help deepen the player’s experience and increase their enjoyment.  

With our games we have tried a mix of revenue models, including paid, paid with in-app purchase, and free with in-app purchases.  Our strategy largely depends on the type of game and expected game play behavior.  In our Amazon games, the model revolves around the use of in-app purchases of virtual goods, although we are starting to experiment with ad-based games whereby users will have the ability to purchase the option to disable ads.  We feel the freemium strategy coupled with in-app purchases provides the greatest ability to delivery quality games to a large audience, while also providing free content for casual players and the ability to upgrade for those players looking for a richer experience.

From the consumer’s point of view, Amazon has done an exceptional job creating a natural and seamless purchasing process that allow users to easily make a purchase and continue playing the game. From a developer’s point of view, we found Amazon’s technical support team to be exceptional. They were attentive, helpful and very responsive to supporting and walking us through the installation process.  

Overall, I’d say that offering IAP in your games/apps is a great way to drive revenue as well as provide enhanced content for users to enjoy.   The Amazon Appstore SDK and In-App Purchasing APIs are well worth installing, whether your game is paid or free.

What is code obfuscation?

If you are ready to submit your app to the Amazon Appstore for Android, you might consider obfuscating your code. Obfuscating your code modifies your source and machine code to be difficult for a human to understand if your app gets decompiled. If you are concerned about your app being reverse engineered, using a tool to obfuscate your code can help a great deal.

Caveat

Not all of your source can be obfuscated, however. If you are implementing In-App Purchasing for your app, the Amazon Appstore relies on certain methods being available to call and provide you with information about a purchase request. If these methods get obfuscated and renamed, the Appstore will not be able to send information to your app. This post is a brief walkthrough on adding code obfuscation to your project.

Proguard

For android apps, Proguard is a code obfuscation tool that is provided to you once you download the Android SDK. The program shrinks and obfuscates your source code.

Setting Up Code Obfuscation for your Project

Prerequisites

This walkthrough assumes you have the Android SDK and Amazon In-App Purchasing API installed and your project already completed.

For help on installing the Android SDK, please refer to their website at http://www.developer.android.com/sdk/installing.html. Download the Amazon In-App Purchasing API by going to http://developer.amazon.com/

Enabling Proguard for your App

To enable Proguard for your Android app, refer to the following documentation from the Android SDK: http://developer.android.com/guide/developing/tools/proguard.html

Edit the build.properties file inside of your project, and add the following line (if you don’t have this file in your project directory, make one):

 ‘Keeping’ the In-App Framework Intact

When incorporating the in-app framework into your library, you will need to specify classes to ‘keep’ and not obfuscate. Add the following lines anywhere in your proguard.cfg file.

Finalizing and Releasing Your App

Now that you’ve fully set up your proguard.cfg and build.properties file, you can run Proguard through the ant  build script for your project.

Obfuscation with another Program

If you are using another program for code obfuscation, to ensure that in-app functionality is preserved, make sure your program does not obfuscate any class under the com.amazon.* namespace, including method names and identifiers. Your obfuscation program must also preserve annotations.

Conclusion and Additional Resources

The code in this article serves as a walkthrough for enabling and using Proguard for release candidates of your app. Sample apps that include the code from this article are provided in the In-App Purchasing API. Again, you can download the SDK by logging into http://developer.amazon.com/

G5 Entertainment participated in Amazon Appstore for Android’s in-app purchasing (IAP) beta program because they had successfully launched over 100 games with in-app purchasing on other devices.  Larissa McCleary, Director of Marketing at G5 Entertainment writes, “We found that by offering a product with IAP, rather than a traditional "lite" or "full" set of offerings, our conversion rates went up as did our revenue on a per title basis. Although our experience on Amazon has always been great, we are thrilled now that IAP is available. This will allow us to continue our business model, but also to allow other developers to partake as well. Eventually, if more and more developers participate, we think we will experience even higher conversion rates, since players will be more familiar with what IAP is and how it functions, making the play experience even more engaging.”

G5 Entertainment takes the approach that if the game is interesting, customers will be more engaged. The maker of popular games such as Virtual City Playground and Mahjong Artifacts, McCleary tells us, “Our basic strategy has been to make the games as fun as possible. We are working hard to optimize and improve our features on an on-going basis.” How do they decide what will be fun for players? Playing the games themselves, focus testing, and team brainstorms have all led to added content.  However, McCleary notes, “In the end we decided that we should let players decide what they want, by giving them as many in-app options as possible.”

The G5 team reported that overall, the integration was quick and simple. McCleary says, “The code was ready in one day, and metadata was entered quickly too.” Comparing their experience to past integrations, the Amazon Appstore compared favorably. “It’s definitely easier to integrate the Amazon IAP APIs than other IAP solutions we have implemented,” notes McCleary.

During the beta program, G5 found their main hiccup in the testing process. G5’s QA team provided feedback that helped the Amazon Appstore improve the testing process by introducing the SDK Tester. The SDK Tester allows a developer to validate common path and edge case scenarios in their app, all without uploading or configuring anything in the Amazon Developer Portal. This approach reduces the friction a developer faces when testing their apps, and allows for rapid testing across any device that supports the Amazon Appstore. Still, the IAP API was well worth integrating for G5, and the G5 team recommends “reading the documents available on Amazon’s Developer Portal and keeping your code simple.”

About G5 Entertainment AB

G5 Entertainment AB is a developer and publisher of high quality downloadable games.  G5 started as the leading mobile game development studio working for Electronic Arts and Disney. In 2009 G5 changed the business model to become a publisher of original games developed by G5 and over 30 partner studios in Eastern and Western Europe and the U.S.  G5 owns a number of successful game franchises, including Virtual City Playground and Mahjongg Artifacts.

Announcing the availability of our Amazon Appstore for Android SDK and In-App Purchasing API to our developer community. The In-App Purchasing API enables you to offer digital content and subscriptions--such as in-game currency, expansion packs, upgrades, and magazine issues--for purchase within apps. 

We created the In-App Purchasing API to make it easy for you to increase customer engagement and monetize your apps on Kindle Fire and other Android devices. With the Amazon Appstore for Android In-App Purchasing solution, you can reach customers with existing accounts who have already bought apps, including millions of Kindle Fire customers. Our simple, secure, and trusted 1-Click purchase experience is easy for customers to use, increasing conversion rates for purchases within your app. Plus, we designed our in-app purchasing (IAP) solution to be simple and easy to integrate so you can be up and running quickly. 

It’s easy to get started from the Amazon Appstore Developer Portal, where you'll find documentation, sample code, tutorials, frequently asked questions, and more.  In the coming weeks, we’ll also be featuring strategies and tips from in-app purchasing beta program partners, such as Glu Mobile, G5 Entertainment, Storm8, and New York Post, here on our developer blog. You can also learn more about our IAP solution from our Introduction to IAP video.

What do our beta program partners say about IAP on the Amazon Appstore for Android?

“Storm8 coordinated closely with Amazon’s team during the initial launch of its IAP beta test, and within two months of integration, we saw revenue grow by tenfold from our game,” said Perry Tam, CEO and co-founder at Storm8, producer of games such as Restaurant Story, Bakery Story, Farm Story, and Fashion Story. “We immediately brought over additional Storm8 games, and in two weeks, not only did our revenue continue to grow, but we had four of the top five free apps in the Amazon Appstore. With the tremendous initial success, we definitely plan on continuing to invest in the platform and can't wait to bring additional Storm8/TeamLava games to Kindle Fire and Amazon users.”

“Amazon's in-app purchasing solution created a great way for us to reduce friction and drive more revenue from our games, as millions of people already have Amazon accounts,” said Michael Ritter, senior vice president Licensing & Distribution at Social Gaming Network, maker of Warp Rush, Dress Up! Fashion, Bird's the Word, and Night of the Living Dead Defense. “Kindle Fire already has a well-integrated storefront and marketplace to distribute mobile games. By enabling in-app purchases we are able to be more flexible in pricing. We can release free games, provide updates, and enhancements, and continue to monetize.”

“We found that by offering a product with IAP, rather than other monetization types, our conversion rates went up as did our revenue on a per title basis,” said Larissa McCleary, director of marketing at G5 Entertainment, Inc., creator of Virtual City Playground and Mahjong Artifacts. “Although our experience on Amazon has always been great, we are thrilled now that IAP is available. This will allow us to continue our business model, but also to allow other developers to partake as well. Eventually, if more and more developers participate, we think we will experience even higher conversion rates, since players will be more familiar with what IAP is and how it functions, making the play experience even more engaging.”

We look forward to seeing how you integrate the API into your apps!