If you are a developer who has had an app in our store for a while, or someone new to our platform, we encourage you to use Amazon Appstore and Kindle Fire badges and branding to help promote your app.  In this article we’ll review badges, other images, links and guidelines for their use with your app and marketing.

Badges:

There are two badges with three color-treatments each that you can use. Here are the badges that you can use to promote the availability of your app in our U.S. store:

The Amazon and Kindle Fire badges above are available in English, Spanish, German, French, Italian and Japanese. The Amazon badges are also available in Portuguese.

You can get full-size downloads of these badges on this page, along with some usage guidance.

Other Images

If you’d like to use a plain icon:

Or if you would like to use a Kindle device image:

You can find links to those resources about half way down this page.

Links to the Amazon Appstore

For web-browser based linking, please:

Use this link structure: http://www.amazon.com/gp/product/ASINnumber/ref=mas_pm_app_name

Replace the bold “.com” with your country marketplace suffix. (.com for US, .de for Germany, etc)

Replace the bold “ASINnumber” with your mobile app’s ASIN (Amazon Standard Item Number) and app name. Please use an underscore (_) to separate the words in the “app_name” portion, if your title is more than one word. You can find the ASIN on the Product Details section of your mobile app on www.amazon.com/apps.

For example, this is the Air Patriots link in the German marketplace:

http://www.amazon.de/gp/product/B008KE3960/ref=mas_pm_air_patriots

For in-app advertising or mobile app-based linking:

In the US:

Use this link structure: http://www.amazon.com/gp/mas/dl/android?p=com.example.package&ref=mas_pm_app_name

Replace the bold portions with the package name of your APK, and app name respectively.

For our international stores:

Use this link structure:

amzn://android?p=com.example.package

Replace the bold portion with the package name of your APK.

NOTE: With any of these link structures, please test the links before using them to make sure that they direct to the correct page or search results.

The link instructions above are pretty much identical to the guidance near the bottom of this page.

Other Useful Guidelines

There is still more good stuff on the handy page I keep linking to. This includes guidelines for correct use of the Amazon Appstore trademark when blogging or using social media to promote your app. I would, of course, be remiss if I failed to mention the legal requirements listed at the bottom of the page. Our attorneys have done a good job of breaking the important points down into easily readable bullet points. Please do look at them, it won’t take long.

Just in case you missed the link earlier, you can read all of this information here, on our developer portal.

Reaching More Customers and Making More Money Per User

In a previous case study, you heard about the tactics that Big Blue Bubble uses to monetize their free to play (F2P) games. In this study, we’d like to share how June Software increased their app exposure by going from an iOS-only producer to an iOS and Android platform producer, and how their presence in the Amazon Appstore has racked up higher Average Revenue per User (ARPU) than any other app store.

June Software is a small San Francisco based software company founded in 2008. They build casual, arcade games and e-learning games for children. Initially June Software only built games for iOS where they have titles such as Math vs. Zombies and Guess the Movie, which is ranked #3 worldwide and is #1 in Australia.

June + Unity + Amazon Appstore = Less Friction, More Revenue

To grow their customer base, June Software decided to address the Android marketplace. June chose to port their iOS games to Android using Unity. Unity allows them to build their app once and deploy it to multiple app stores, including the Amazon Appstore.

When we asked about their experience on Amazon apps store, June Software Director Products Saurabh Jain said:  “On Amazon, we have seen 2x times the ARPU [we see] from Google Play, and 1.2x [more than] than Apple AppStore. The overall downloads aren’t there yet, but the revenue makes it a very good market for us.”

Increasing Time in Games Increases Potential Income

One effective strategy that Saurabh implemented is that they have integrated Amazon IAP and GameCircle features in their games, which increased potential revenue and player engagement. GameCircle includes features such as leaderboards and achievements that keep players engaged and can increase user session time and session frequency, giving uses more opportunities to make IAP purchases. And it works on Android and iOS. This is exactly what June Software needs for their games available for both platforms.

What can you do?

• To learn more about using Amazon GameCircle in your Unity apps, read this blog post and refer to this documentation.
• To learn more about using Amazon In-App Purchasing in your Unity apps, read this documentation. To see how Mad Menace Games used the Amazon IAP Plug-In for Unity, read this post.
• For additional information on Amazon Unity Plug-ins, read this. 

About Kinetic Art

Kinetic Art, an Israeli startup established in 2010, is the publisher of the highly popular cooking app Look & Cook. Kinetic Art's core technology and intellectual property revolves around in-app ecommerce optimization.

Recently, Kinetic Art published Look & Cook to the Amazon Appstore (download here) their first ever-Android version. I had a chance to sit down with Dudu Mimran from Kinetic Art and talk about Kinetic Art’s experience publishing on the Amazon Appstore, what it was like implementing the Amazon Mobile Associates API, and what type of success they have seen so far.

“Look and Cook is a cooking and now a shopping app, thanks to Amazon’s Mobile Associates API. We are building a platform for building cooking apps.” - Dudu Mimran.

Why start with Amazon? A better user experience.

Having found early success on iOS, including an advertising campaign on Pinterest, the team decided it was time for an Android version. For Kinetic Art the most important thing for Look & Cook was ensuring a great user experience. They were confident they could achieve this vision on Kindle Fire as they only needed to target a single device vs a multiple of Android devices. “On Amazon, you can focus a lot on Kindle. With Google Play you have to make sure you having everything looking good on many, many devices. We decided it would be a much easier transition going from iOS to Amazon because of this.”

Look & Cook was able to leverage Amazon to create a culinary lifestyle experience by integrating ecommerce into the food and culinary world. The current version of Look & Cook now has numerous physical goods related to the cooking of the selected recipe. “We created a small shop within each recipe. The tools that are included in the app are recommended by the recipe creator to make the recipe perfectly. In general, this is what our investors have in mind. Our main business model in the future will be ecommerce. We are not there yet, but this is a great step. We are betting everything on ecommerce and we already have purchases. People are buying for sure,” declares Dudu.

“Look and Cook is a cooking and now a shopping app, thanks to Amazon’s Mobile Associates API. We are building a platform for building cooking apps. Amazon’s Mobile Associates API really excited us because we have always wanted to integrate ecommerce but it’s something very hard to do as a startup. Since Mobile Associates launched it has made it much easier for us. We are very happy working with Amazon,” says Dudu.

Amazon Customers: More Engaged

Even though the team has seen a smaller number of app downloads on Amazon vs. iOS people are definitely buying goods and they have already seen differences in the behavior of customers. “We have two types of users on Amazon: those that use it on an ongoing basis and those that love it for cooking. We also see those that love it for the very first time. They are more engaged on Amazon, and if I compare the amount and depth of reviews, then totally, people are much more engaged into the app itself,” says Dudu.

According to the team, once they understood the basics of integrating the API for Amazon Mobile Associates, things progressed quickly. “It was very easy, and it just works!” says Dudu.

“Our main business model in the future will be ecommerce. We are not there yet, but this is a great step. We are betting everything on ecommerce and we already have purchases. “

Figure 1- Look & Cook running on a Kindle Fire HDX 7”

Figure 2- Tapping on Shop will bring up a physical good for that recipe you can buy with the Buy Now button.

Figure 3- Clicking Buy Now takes you right to the product from Amazon without leaving Look & Cook

Figure 4- Look & Cook’s category of recipes

Kinetic Art projecting 8-10x growth

To measure success the team built a detailed level of conversion measurement. For example, they know how many people download the app, navigate through the app, navigated to an extended view, and buy products. In the future, one of the improvements will be creating greater exposure to other random products and not forcing people into the ones the app recommended.

It’s too early to tell how much money the team will be making but already they are seeing purchases. “It’s less important for the number at the moment, behavior is what is very important. Really getting customers used to the behavior is important. They are not accustomed to buying within the app. Now we are working on several angles: distribution, volume of users, exposure of more products, and then quality of product and selection,” says Dudu. 

When asked about potential growth, the team projects as much as 8-10x growth once they start really marketing to users. Their favorite part about working with Amazon? “I would say the personal touch. This is very, very important to us and a huge differentiator. From a user perspective, Amazon customers are much more engaged and seem to be people that buy.”

You can check out Look & Cook in the Amazon Appstore here and find out more about the Amazon Mobile Associates API here.

-Dave (@TheDaveDev)

Two years ago, Sean Sheedy, saw an opportunity to teach his boys more about mobile app development. He decided to take his sons Tommy and Ian with him to MoDevEast and participate together in a hackathon. These three were our big winners from the MoDevEast competition. It all started out with Sean bringing paper, pens and other supplies so that the boys could help out by drawing the app’s user interface in prior MoDevEast competitions. Once they came up with the user interface Sean would code whatever ideas the boys came up with.

Figure 1Sean with his sons Tommy and Ian

His oldest son Tommy (ten at the time) would always talk to other attendees and sponsors from the hackathon and would work alongside them. When one of the attendees gave Tommy an iOS app recipe, it wasn’t long after that Tommy had an entire app running and needless to say dad was impressed.

At the recent MoDevEast 2013 conference Tommy brought his friend Devin and his Dad to the conference too, bringing the teams total membership to four. 

“We were trying to decide what app to write,” recalls Sean, “Devin’s Dad and I like to get together and jam on the guitar. We thought about doing an app called Jam Session. The idea that we tried to implement was an app that would let you playback a track that somebody else recorded and while it plays back you can record your own track. I found two API’s called Audio Track and Audio Record for Android. We found that it was possible to do this and then figured out how to make the app work.”

“Tommy investigated early on of what it would take to make this work on a Kindle. He saw that it would be really easy to port over to the Kindle because it’s basically Android,” says Sean. “Tommy saw the benefit of creating the design and then began writing code. We initially built it for Android. The API we ended up implementing was really a simple audio playback. “

Figure 3 Sean and the boys using post it notes to flush out the app user interface

“There was no porting involved – it was intended to run on any Android device and that includes the Kindle.” - Sean

So what was the process like getting their Android app running on Kindle? “It was a no brainer to port this over to Kindle. It basically ran right away. We basically did no work,” Sean says. “The only thing that would have been a deal breaker is if we had used vendor-specific or unpublished APIs. Nothing stood out to be an issue. There was no porting involved – it was intended to run on any Android device and that includes the Kindle Fire. “

What about the Kindle development environment? Since Kindle is Android it’s just like any other Android environment using Eclipse. “In development it’s really cool that I can plug the Kindle in and it’s just like any Android device. That is REALLY nice.” says Tommy. 

So what do Sean and the boys envision for the future? “We would like to be able to make it easy to buy the music that people are jamming to in our app. You can start off by buying the music you want to jam to and make that the base track and then add your tracks to it. Amazon’s Mobile Associates API would help us do that.”

“In development, it’s really cool that I can plug the Kindle in, and it’s just like any Android device. That is REALLY nice.” - Tommy.

Did the boys have fun on this father and sons hackathon adventure? “Tommy thought this was our best concept yet. We didn’t win the top prize, but we won the Kindle Fire and some money,” says Sean. “Pretty much every hackathon I’ve gone to I’ve gone to with the kids. The boys are getting a lot from the experience, and I highly recommend this to any tech parent.” 

Amazon Mobile Associates

Interested in selling Physical Goods in your Android Apps using the Amazon’s Moble Associates API that Sean mentions? Be sure to check out our Mobile Associates Blog Posts and Developer Portal for full details.

-Dave (@TheDaveDev)

Today, we’re extending Amazon Coins to all Android devices with the Amazon Appstore installed.  Amazon Coins is a way for Amazon Appstore customers to buy and enjoy Android apps, games, and in-app items for less. Customers can save up to 10% on apps and games by purchasing Amazon Coins, while developers continue to get their full 70% revenue share.

More Ways for More Customers to Buy Your Apps

Since the launch of Amazon Coins in the US, UK, and Germany in 2013, customers have already purchased hundreds of millions of Amazon Coins and are actively using them on Kindle Fire devices, representing real dollars to developers.

Now, users of the Amazon Appstore on Android will be able to use Amazon Coins to purchase apps, games, and a broad range of in-app items on any Android device running the Amazon Appstore in the US, UK, or Germany. If a customer is already a Kindle Fire user, he or she will automatically see their existing Coins balance on their other Android devices in addition to their Kindle devices.

How You Can Benefit from This News

We have already seen developers benefit from customers using their Amazon Coins to try out and explore new apps and games. Now that Coins are available to an even larger audience, you can take advantage of the opportunity by making sure your app is available on the largest number of devices.

Check Device Availability

Check your device availability to make sure your app is available to as many Coins-enabled customers as possible.  Checking is easy, and adding supported devices is not much harder. Follow these steps below to get started:

1.      In the Amazon Developer Portal, go to your app’s detail page.

Under the Binary File(s) tab, check the Device Support section for “All non-Amazon Android devices…” (see sample below).

2.      If your app has “All non-Amazon Android devices...” and the Kindle Fire devices listed, then you’re done!

If the entry is missing “All non-Amazon Android devices...” (as shown below), you can change that.

Change this by: a) Modifying your AndroidManifest.xml, b) Creating an ‘Upcoming Version’ in the dev portal, and then c) Submitting the .apk with the new manifest file. Here are the steps to do that:

a.       If you have verified that your .apk will run successfully on some (or most) other Android devices, make sure you reference supported devices in your AndroidManifest.xml file by using <compatible-screens /> or <supports-screens />  (please make sure to increment the version number of your app when you modify the manifest).

b.      Click Add Upcoming Version in the dev portal.

While in the new ‘Upcoming Version’ section, go to the Binary File(s) tab and check all the appropriate boxes.

c.       Upload the .apk with the new manifest.xml, make sure the other tabs are complete (and app version number is different), and re-submit your app.

3.      If your app is not available on Kinde Fire devices, you can use Amazon’s App Testing Service to get the info you need in about a minute. Just drag and drop your .apk into the tool to get your results! You can also check out common reasons for incompatibility, and check out the documentation on our dev portal.

Questions

If you have any questions about Amazon Coins or device availability, please check our dev portal, or contact one of our developer support professionals.

Setting up your Kindle Fire device for testing and debugging is a simplified process thanks to Android Debug Bridge (ADB) support.  Since questions around ADB driver support have come up on Stack Overflow and our developer forums I thought it would be beneficial to walk through the setup process. 

Certain development tools referenced in this post are provided by third parties, not by Amazon. Any links to these tools will take you to third-party sites to download and install them.

Getting Started

Note – this post was updated on April 16^th, 2014 to reflect changes in the Amazon Android SDK addon.

First, ensure your development computer has at least one package of Kindle Fire system images installed. This is critical because the package includes the vendor identification needed for ADB to recognize any of the physical Kindle Fire tablets.  This is done through the following steps:

• Ensure you have the Android SDK already installed
• Launch the Android SDK Manager
• Under Tools, select Manage Add-On Sites, and enter the following url: http://kindle-sdk.s3.amazonaws.com/addon.xml

• Select Close and wait for the list of available packages to refresh
• Select Kindle Fire USB Driver, Kindle Fire Device Definitions, and optionally the Amazon AVD Launcher.

• Select at least one Kindle Fire image so that vendor information is available for ADB.  I’ve chosen to select the three Kindle Fire 3^rd Generation images (API Level 17).

• Accept the license agreements and install.

For complete information about setting up your development computer and installing the SDK packages, see Setting Up Your Development Environment.

Uninstalling existing Windows drivers

If you installed a previous version of the Kindle Fire USB driver then take the following steps to remove the previous USB device driver and force re-installation of the driver.

• Connect your Kindle Fire tablet to the USB port on your development computer.
• On the development computer, from the Start menu, right-click Computer, and then click Manage.
• In the left pane, under Computer Management, expand System Tools, and then click Device Manager.
• In the right pane, expand Portable Devices.

• Next, Right-click Kindle and then click Properties.
• In the Kindle Properties window, on the Driver tab, click Uninstall, and then Confirm.

• Finally, unplug your Kindle Fire tablet from your computer.

Enabling ADB on the Kindle Fire

Next, we need to turn on ADB support on our actual Kindle Fire device.  Follow these steps:

• On your Kindle Fire tablet, go to Settings.
• On a third-generation Kindle Fire tablet, tap Device.  On a second-generation Kindle Fire tablet, tap Security.  First-generation Kindle Fires already have ADB enabled by default so no action is needed.
• Set Enable ADB to On, and then accept the pop-up warning message.       

As a security precaution, you should set Enable ADB to Off when you are not trying to connect to the Kindle Fire tablet to your development computer.

Installing Windows ADB drivers

First, ensure you have enabled ADB on the Kindle first as described above.  For the USB driver to install correctly, Windows must recognize the device as Android Composite ADB Interface during installation. If ADB is not enabled, Windows instead recognizes the device as Portable Devices.

Do the following to install the Kindle Fire USB driver:

1. In your Android SDK directory, at \extras\amazon\kindle_fire_usb_driver, run KindleDrivers.exe, and then follow the instructions on the screen.

1. Connect your Kindle Fire tablet to a USB port on your development computer.
2. From Start, click Control Panel, and then select Device Manager.
3. In Device Manager, under Kindle Fire, verify that the device appears as Android Composite ADB Interface.

Next, do the following to detect your Kindle Fire tablet through ADB:

1. Open a command prompt window.
2. Change directory to your Android SDK platform-tools directory.
3. Run the following commands and confirm that the serial number for your Kindle Fire tablet appears in the list of devices.

If the serial number does not appear after running adb devices, do the following:

1. Change directory to your Android SDK tools directory.
2. Run the following command:

1. Change directory back to your Android SDK platform-tools directory.
2. Run the following commands:

If your Kindle Fire device still does not show up you may need to reboot your development machine and then try again.

Installing Mac OSX ADB drivers

Perform the following steps if your development computer runs OS X:

1. Connect your Kindle Fire tablet to a USB port on your development computer.
2. Open a terminal shell and navigate to your Android SDK tools directory.
3. Run the following command to update ADB.

4. In the terminal shell, navigate to your Android SDK platform-tools directory.

5. Run the following commands and confirm that the serial number for your Kindle Fire tablet appears in the list of devices.

If your Kindle Fire device does not show up in the list of devices you may need to reboot your development machine and then try again.

You should now be able to fully test with your Kindle Fire device over the Android Debug Bridge.  For additional information on enabling ADB for Kindle Fire Devices, see Setting Up Your Kindle Fire Tablet for Testing.

-Dave (@TheDaveDev)

If you develop apps or games with Unity, you may already be using Amazon’s GameCircle plug-in for Unity to integrate cross-platform leaderboards, achievements, and game data synchronization.  The plug-in works on iOS, Android, and Fire OS, connecting your app to Amazon’s GameCircle service.  Its leaderboards and achievements encourage friendly competition and replay, while its Whispersync for Games component backs up game data to the cloud, improving the customer experience.  With GameCircle, gamers won’t lose their progress if they reset their device or buy a new one.

If you haven’t used the GameCircle plug-in yet, you can now download it from the Scripting/Integration section of the Unity Asset Store.  Accessible directly from within the Unity development environment, the Unity Asset Store makes it fast and convenient to add editor or game functionality through third-party extensions like the GameCircle plug-in.

This official GameCircle plug-in is compatible with iOS and Android phones and tablets, as well as Kindle Fire, Kindle Fire HD, and Kindle Fire HDX devices.  Add the plug-in to your project to access GameCircle leaderboards, achievements, and Whispersync for Games.

In addition, the GameCircle plug-in also works with the Unity Social API, which provides a unified interface to social back-ends such as Game Center and Xbox Live.  Set the active social platform to GameCircle and calls to the Unity Social API will pass through to the GameCircle service in the same way:

#if UNITY_IOS || UNITY_ANDROID
Social.Active = GameCircleSocial.Instance;    
#endif

Since Unity’s Social API is designed to be a generic interface that works across many services, it doesn’t support every feature of every back-end.  GameCircle leaderboards and achievements work seamlessly, for example, but Unity’s Social API provides no hooks for game data synchronization.  To use some advanced features of GameCircle, like Whispersync for Games, simply call the API through the normal GameCircle interface.  It’s easy to use the two APIs side-by-side, and the plug-in includes a sample scene to help you get GameCircle and Unity’s Social API up and running together.

Check out the official GameCircle plug-in in the Unity Asset Store.  It’s easier than ever to get started integrating GameCircle’s leaderboards, achievements, and Whispersync for Games in your Unity-based game for most mobile devices.  You can also visit our developer portal for more detailed information about using GameCircle and Unity together, as well as links to help you call other Amazon services from your Unity projects.

Creating an application using Amazon's Mobile App Distribution Program is a great way for developers who have hosted web apps to create downloadable apps available on the Amazon Appstore. Web app developers benefit from the increased discoverability that the store provides when users are searching for new apps, as well as being reminded to use the web app by the icon on their device's home screen afterwards. In addition, all of a user’s linked devices that use the Amazon Appstore will have the icon waiting in their Cloud list of apps as well.

And because web apps are hosted online, developers have increased flexibility to re-use existing assets and make changes or fixes to the app quickly and easily, without having to re-create a new app that has to be re-installed by the end user. But what happens if the user wants to use the app offline? Obviously, if the app relies on live server-side content - such as streaming videos or airline reservations - then obviously it's not going to work. But if the web app is self-contained and doesn't need to talk to a server for its core functionality - like most games - then being able to take the app offline is something that should be an option for users.

Happily, enabling your web app to be used offline can be done using HTML5's built-in Application Cache with only a few small changes to your code. Below I'll outline the steps you need to take to create a basic offline web app. It's surprisingly easy to set up, but beware! Application Cache has a well deserved reputation for being difficult for developers to get a handle on.

Offline Web App Walkthrough

1. Create Manifest File

The first thing you need to do is create an HTML5 manifest text file with a list of every asset file your web app requires - HTML, JavaScript, CSS, images, icons, fonts, etc. The manifest file can have any name you choose, but we'll use app.appcache to be clear and to avoid overlap with other types of manifest files.

Here's the content of a basic manifest file:

CACHE MANIFEST 
# Version 1.0 
CACHE: 
main.js 
main.css 
logo.png 
NETWORK: 
*

- The first line needs to be CACHE MANIFEST.

- The second line in this example is just a comment, but is useful to make changes to your web app by simply incrementing the version number. Note: Only changes to the manifest file will invalidate the cache.

- The third line begins the CACHE: section where you list out the asset files used by your web app, either relative to the location of the manifest file, an absolute path or complete URL. Note: DO NOT list app.appcache in your manifest.

- The NETWORK: section has a wildcard which permits the browser to download files that are not listed in the CACHE: section. Note: Without the NETWORK: section, the browser will ONLY re-request files listed in the CACHE: section after the initial page load.

2. Confirm Server Settings

You need to also make sure your web server serves the correct MIME type for the manifest file. For Apache, it looks like this:

AddType text/cache-manifest .appcache

You also need to makes sure the manifest file is not being cached on the server. If the HTTP Cache-Control header for the manifest file doesn't update, or a 304 Not Modified is return, then the web engine won't be able to see if the manifest file has been changed or not, which is the only way to invalidate the offline cache.

3. Add Manifest Attribute

You then need to add an attribute to the tag of every HTML page you serve pointing at the manifest file, like this:

<html manifest="app.appcache">

4. Add Update Script

Finally, you need to make sure your app updates itself if the manifest changes - the easiest way to do this is to add this bit of JavaScript to your main HTML:

<script>
window.applicationCache.addEventListener('updateready', function(e){
    window.location.reload();
});
</script>

5. Test

Your web app should now be offline enabled! If you have Python installed, you can test this by setting up a local server to see what's happening both on the server and in the browser.

beattier@amazon.com:~/html5demos/offline$ python -m SimpleHTTPServer

Serving HTTP on 0.0.0.0 port 8000 ...

1.0.0.127 - - [21/Jan/2014 13:42:52] "GET / HTTP/1.1" 200 -
1.0.0.127 - - [21/Jan/2014 13:42:52] "GET /app.appcache HTTP/1.1" 200 -
1.0.0.127 - - [21/Jan/2014 13:42:52] "GET /main.css HTTP/1.1" 200 -
1.0.0.127 - - [21/Jan/2014 13:42:52] "GET /main.js HTTP/1.1" 200 -
1.0.0.127 - - [21/Jan/2014 13:42:52] "GET /logo.png HTTP/1.1" 200 -

... 

1.0.0.127 - - [21/Jan/2014 13:43:12] "GET /app.appcache HTTP/1.1" 304 -

By modifying the manifest file and reloading, you'll see that all the files listed will be re-downloaded again.

You can also connect the Amazon Web App Tester to see the client side of the process as well by using Remote Debugging. (See our previous overview of setting up the Tester here.) In the screenshot above, I've connected to a Kindle Fire HDX and loaded a demo offline web app stored on Github. By looking at the Resources tab and drilling down into the Application Cache folder, I can see the assets that are cached locally, and a log of the Application Cache events.

Application Cache Gotchas

This is just a basic way to setup an offline web app. There are more options that you can add to your manifest file, more events you can track in JavaScript and more functionality you can use to make your web app's offline experience much more seamless to the end user. Check out the links below for more information.

Conceptually, it's important to understand that once you've enabled a manifest, your web app is now offline first and forever. Let's repeat that for clarity: OFFLINE FIRST AND FOREVER.

OFFLINE FIRST means:

- Your web app's files will then always be loaded from the offline cache first, and then a request will be made to the server for the manifest file to see if there have been any updates.

- The browser will not automatically refresh if the manifest has changed. It will in fact download the files from the server, but it will wait until the next time the page is requested to use them. This is why the script in step 4 above to detect a manifest change and immediately refresh the page is important.

FOREVER means:

- The only thing that can invalidate the offline cache and trigger a re-download of files is a change in the contents of the manifest file - not just the timestamp.

- There is no programmatic way to invalidate the offline cache from the browser. Even changing or deleting the manifest attribute in the tag will not invalidate the cache.

- Until the browser requests a manifest and receives a 404 or 410 from the server, it will continue to consider the web app as being offline and use the last downloaded version, rather than updating from the server.

Summary and External Resources

The info above should be able to get you started with offline web apps. Once you've added in the manifest, your web app will be available offline the next time your users load up your app. Fair warning: This can be a tricky feature to implement - especially if you misconfigure or forget some of the steps above. Getting the browser to let go of the manifest and refresh your code can be incredibly frustrating. I think the upside is worth it though, as enabling your web app to be used anywhere a native app can be used is incredibly satisfying.

To get more information about Application Cache, I encourage you to check out these great articles which dive into the topic in even more detail.

·         http://diveintohtml5.info/offline.html

·         http://www.html5rocks.com/en/tutorials/appcache/beginner/

·         http://www.html5rocks.com/en/mobile/workingoffthegrid/

·         http://alistapart.com/article/application-cache-is-a-douchebag

In future posts, I'll expand on offline apps by looking at topics such as offline data storage and efficient caching strategies.

-Russ (@RussB)

Last week, I wrote to tell you about the new Dolby SDK that makes it easy for you to optimize the sound on the device to match the different kinds of audio you use in the course of your app. This week, we have some feedback from a developer who has implemented the Dolby Plug-In for their app on Kindle Fire.

Luxurious Animals is a game developer in New York. They wrote the casual game Lux Ahoy!, a netmagazine.com Top-10 game. Before working with Dolby Digital Pro, they didn’t consider audio to be a key component.  However after using the Dolby Plug-in, Luxurious Animals had this to say: “The API created a much richer and more immersive experience, making the game feel more exciting and absorbing.  It really took our game to the next level.”

Overall, Luxurious Animals found the Dolby Plug-in to be easy to work with and required no changes to the overall workflow:

“Adding the Dolby magic to our app was as easy as linking a JAR file with our project and calling Dolby-specific methods from our app. We used the Game audio profile inside the API, which creates a ‘live’ space to best bring out the effect of fast-moving objects in the audio. The API also offers Music, Movie and Voice profile options.  We had Dolby capabilities in the game up and running in less than 15 minutes. The API package comes with a Javadocs and a quick-start guide along with a sample application showing how Dolby APIs should be invoked.

Today, we have a fun casual game that not only has great-looking graphics, but also a rich soundtrack that pulls users in and holds their attention. We are confident these enhancements have increased the overall experience for our customers on the Kindle Fire HD.”

I’m thrilled that Luxurious Animals has been able to improve the customer experience for relatively little effort; it speaks well to the smart API design by the Dolby development team.  

To learn more about the Dolby Digital Plus SDK, please read the previous blog post on the topic here, or get the SDK directly from Dolby here.

This isn’t the first time Amazon and Dolby have collaborated. Amazon and Dolby worked together on hardware and software enhancements for the Kindle Fire HD and HDX line of tablets for their launch, delivering Dolby Digital post-processing for native apps. But now Dolby has raised the bar again with Dolby Digital Plus, and the new Dolby Audio APIs for Kindle Fire. (Fear not, Unity fans. There is a Unity plug-in for you too.)

When you use the Dolby Audio Plug-in APIs, you can choose from four audio profiles to tune your sound profile to match the audio use in your app. For example, you can tune your app to use the Voice profile for dialog-heavy parts of your app, and the Game profile for first-person-shooter action. Here are the profiles you can choose from:

-Music: Applies equalization and dynamic range control to enrich instrumental and vocal quality in recorded music

-Movie: Clarifies the dialogue while providing the best representation of the full dynamic range of the program

-Game: Creates a ‘live’ space to best bring out the effect of fast-moving objects in the audio

-Voice: Customized for the reproduction of speech patterns and the tonal range of the human voice

This lets you deliver an optimized audio experience to your users, and it takes very little time to do so. Here are the high level steps to implement this API:

1.      Load the Dolby JAR file and import the DolbyAudioProcessing libraries

2.      Create a OnDolbyAudioProcessingEvent listener

3.      Call getDolbyAudioProcessing to get an instance of the Class (only done once for lifetime of the app)

4.      Wait for the app to connect to the DolbyAudioProcessing handler

5.      Instantiate the audio profiles as needed to in your app (Voice for dialog heavy parts, Game for FPS parts, etc…)

6.      Restore default audio behavior if your app is in the background

7.      Restore default audio behavior by releasing the Dolby instance on destroy

Setting the sound profile to use at different points in your app is pretty easy (see below).

You can set profile to Music, Movie, Game or Voice as appropriate at that location in your app.

Overall, integrating the API takes about an hour and does not require re-designing any logic or workflow. It’s a small investment for a big win.

You can download the free sample apk right away so you can hear for yourself how nice this is. To download the API, you need to sign up for a free developer account with Dolby (which took me less than 30 seconds).

Dolby has done a good job of making this easy to deploy. When you download the API package, you’ll get everything you need to get started, including javadocs, a quick start guide, and sample code showing exactly how to invoke Dolby APIs. You can download the free Dolby Audio Plug-in on this page, and learn more about Dolby Developer Services on their developer home page here.