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Microsoft's Project Astoria has leaked letting Windows 10 Mobile sideload Android APKs directly

Ever since Microsoft announced their Bridge technologies at Build 2015 questions about how they work (and how well) have been asked. The tools let developers port over Android apps (Project Astoria), iOS apps (Project Islandwood), web apps (Project Westminster) and classic Win32 apps (Project Centennial) to Windows 10 including phone.

This morning, the actual tools for Project Astoria have leaked onto the web and users can freely (and illegally) download Android APKs and sideload them to their Windows Phone running Windows 10 Mobile. This follows yesterday's leak of the documentation for the project.

As it turns out, the tools are very powerful with the only limitation being the inability to run Google Play apps, which is in many ways trivial (this also means Snapchat will not work). Indeed, Windows Central has learned these tools are far from final and that the upcoming TH2 release has many more improvements, promising a much better user experience.

Microsoft going all out courting iOS and Android developers for Windows 10

Windows Central is not linking to the file nor providing instructions on how to sideload. Simply put, the software is not finished, and the ability to steal Android apps is not something we would like to promote. We also don't need the traffic. Obviously, this situation is unique and Windows Central is caught between reporting on this and aiding and abetting it.

Developer Concerns

The idea that developers can simply and directly convert an Android APK to a Windows 10 APPX is both fascinating and a bit disturbing for developers. Here is why:

Android developers – Their apps can now "easily" be downloaded and installed on Windows Phone, often without paying or abiding by the software's EULA. Of course, this not new, as this situation has always existed for Android developers.

Windows Phone developers – This situation, however, is unique. Windows Central has already spoken to a few developers who are distraught about how easy it is to port. Indeed, a few of them feel burned and are ready to give up on native Windows Phone app development because why bother?

Certainly Project Astoria is controversial. On the one hand, why should developers now make Windows Phone apps when they can just do Android and port it over?

The alternative argument, of course, is that developers want to write a native Windows 10 app so that it can run on the phone, PC and other Microsoft technologies. These are places where Android apps cannot go even as a port.

Once again, this is a chicken and egg situation for Microsoft. If developers port over their Android apps to Windows Phone, Windows 10 Mobile's market share can grow. If it grows, developers can re-write their apps for all of Windows 10 to target an even larger market.

Then again, developers may port Android apps (or not) and Windows Phone native app development languishes and goes nowhere.

For Windows Phone users

Putting aside the developer situation, which at best is now very unstable, what about consumers?

Assuming developers bother to port their apps – something that remains to be seen – certainly those using a Windows Phone could see a big boost in available apps and games from these Bridge tools.

Boosting apps and games in the Store, after all, is the point of the projects.

The Android apps are not just run in-situ but can plug into various components of Windows 10 including notifications and Live Tiles. These are the 'bridges' to native functions that Microsoft refers to in the documentation.

This ability is why these tools are so significant and impressive. However, besides a few enthusiasts going through a cumbersome process to sideload Android apps, it is not clear that this method will ever see the light of day.

We do know that Microsoft is not at all happy with today's leak. However, they are making the best of it by collecting a ton of new telemetry from those who are using these tools, so if you do this, consider yourself part of an experiment.

To our developers, what do you think of today's news? Will you continue native Windows 10 development for mobile or give up for Android and iOS?

Request and Warning

Windows Central is taking a hard line on posting of links to these tools, direct or indirect. Please do not post links or directions in comments as you risk having the post deleted. Continued abuse of this rule may result in account termination.

Daniel Rubino
Executive Editor

Daniel Rubino is the Executive Editor of Windows Central, head reviewer, podcast co-host, and analyst. He has been covering Microsoft here since 2007, back when this site was called WMExperts (and later Windows Phone Central). His interests include Windows, Microsoft Surface, laptops, next-gen computing, and arguing with people on the internet.

464 Comments
  • Wow, thats good news
  • Getting more apps on Windows phone promotes the platform and removes the primary barrier to entry. Remember, if developers want their app on the 1 billion desktop devices they still need a native app. But this may help the mobile space in the meantime.
  • That's how I see it too. Still, some developers I have spoken with feel a little betrayed. This of course could be just a knee-jerk reaction, so it will be interesting to see how it progresses.
  • I suspect Microsoft has purposely leaked it... To see the market reaction... Definitely... Posted via the Windows Central App for Android
  • They have not and they are not happy about it. It is still quite incomplete and does not show the tools in the best of light right now. Look at all the talk about piracy, etc.
  • Pretty silly to talk about piracy on W10M with 0.1% market share when you can do the same on Android with 80% market share.
  • Yeah when its a staple for any bbos10 user to tap into googleplay/Amazon app store. Its odd for wc to take a stance when cb wont
  • They won't be able to. If you read the article you would know that the apps have to be modified slightly in order to work. So, apps downloaded straight from Amazon or Google Play won't install. Posted via the Windows Central App for Android
  • Agreed. Besides, if they were to leak it, this definitely won't be the correct time to do that.
  • @Daniel: Small typo there: "The idea that developers can simply and directly convert an Android APK to a Windows 10 APPX ..."
  • Fixed, thanks.
  • Piracy may be a concern, but Android allows you to install random apks as well, so I don't see the problem. Also, I just used it to install Slack (free chat app), and it works almost perfectly despite complaing about the missing Google Play services. The only thing not working is the push notifications. And it took me less than 10 minute to do that, everything worked as intended, so the tools are great.
  • I wouldn't say android "allows" anything... You have turn of the third party security...
  • Same in Windows. You have to enable developer mode, otherwise you can't sideload them.
  • And turning on all sources isn't exactly rocket science.. This would do nothing for piracy
  • They are NOT random, somebody spent time writing them. And they are NOT modified to work on another platform as this is doing.
  • Did I say sombody didn't spend time writing them? Random was probably not the best word, I meant apps not available from the official store. In any case, on Windows the Android apps are not modified either. Windows Mobile 10 contains an Android virtual machine (linux under HyperV) that runs the unmodified apks. And as you probably know, it's easy and usually legal to get the apk packages for the free apps. And since you seem to imply something with your use of caps lock, I only intend to use this for free apps. And I will be even happier when the devs start uploading them to the Windows Store so I don't have to mess around with sideloading. In fact the developers of the app I tested (Slack) were quite happy when I told them that I installed it on my phone.  
  • Piracy may be a concern, but Android allows you to install random apks as well, so I don't see the problem.
    You don't see the problem? We don't want Windows 10 Mobile to become the next Android, do we? As of this moment, Windows Phone is the most secure, stable and fast Mobile OS. Let's let it stay that way, shall we?
  • No, I want to Android apps on Windows 10 over!
  • > Windows Phone is the most secure, stable and fast Mobile OS I'll give you secure.  Stable I'd need to see some stats on.  Fast?  No way.  WP is a lag-fest.
  • BS. On my Lumia 930 every well written app runs like butter, and so does the OS.
  • Smooth isn't the same as fast. Windows Phone is slow. The animations and loading times are annoying. Posted via the Windows Central App for Android
  • I don't use Andrioid a lot. But from the time I have played around with it, I don't see things like you see them. I've only had 1 Windows Phone, the 520 where I felt like things didn't load instantly for me
  • No, they don't. And I've got one word that any Windows Phone user has undoubtedly come to rue as proof: "Resuming..."
  • Oh its fast all right. Haven't reset my phone in a year and still runs like it used to on the first day. Windows phone is secure because its sandboxed. Testing has to do with the the OS suspending the apps. Happens on win 8.1 too. Haven't seen this on win 10
  • Hahahah go try Android! i doubt it
  • You don't see the problem? We don't want Windows 10 Mobile to become the next Android, do we? As of this moment, Windows Phone is the most secure, stable and fast Mobile OS. Let's let it stay that way, shall we? While I agree with the sentiment, the reality is that unless the Windows Mobile market share grows to something like 10% soon and becomes somewhat profitable, Microsoft will probabil scale down the phone and phone OS part of the business even further or even give it up completely. They are already launching Android and iOS apps before Windows Mobile. So I think of this as a last chance for Windows phones. The choice isn't between being the most secure and stable or not. The choice is between being scrapped or not. I'm a big Windows Phone fan, but even I was considering an Android phone due to the the missing apps that I need for my job. Astoria fixes that problem.  
  • Is the developer concerned that when the app is being ported, it's not being feature-full or paid use being implemented? Or salty because someone beat them to bringing their app to the platform?   If I saw people porting over my app like crazy to their phones, that's obvious reason enough to show people want that application on their devices.. Which in turn sounds like a good piece of the share to make your application to the platform to begin with (If they haven't seen that before) no?
  • So Android developers will know their apps are showing up on Windows Phones? I mean, they'll start getting usage stats reported or something and it will say "4.5% of users on Windows 10 Mobile" or something like that? Or it will still think it's an Android device? Or, they don't get usage stats like that at all? I'm confused on how developers would even know people were doing this, particularly for apps that don't even connect to services.
  • @Mristian - cant ignore the legality though. The main issue though is if the dev don't want their app on winp for whatever reason.
    It's their choice regardless how we may feel about it.
    So worth highlighting, but it is a fraction of a fraction of piracy that happens in the overall scheme of things though.
  • You need to go write a quality app and come back and let me know how hard you worked at it, then to have it stolen.
  • No, I don't.
  • There is NOTHING illegal about this, and it isn't piracy. Please fix your article.
  • You might want to re-read all those T&C's, EULA's, atlases, statutes etc.
  • how is it related to piracy?  calling taxi apps like uber - which is bitaksi for turkey - and other popular apps are not available on windows phone. and these apps are already free. developers are taking that risk by uploading their content to play store already. so if these daily apps that are completely free for android users can work easily on windows phone without doing so much work, that is especially good thing for us.  Just to clarify, yemeksepeti, bitaksi, enpara.com apps are examples for Turkey and these apps will never come to Windows Phone if the Project Astoria doesn't exist. And again, I am sorry for you Daniel, but wmpoweruser once again steal the all show from windowscentral. I used to read all the rumors of windows phone once and that is upsetting me that windowscentral has become a follower especially for  windows phone.
  • It is certainly not a leak on purpose.  But this leak does have several implications: 1.  It proves that Project Astoria bridge and W10M Android Subsystem work technically, even it is not finished yet.  The WP users generally feel very upbeat for this development. 2.  It would pressure and encourage the Android app developers to take the Project Astoria seriously.  To submit the ported apps to Windows Store for a legal distribution is the only way to stop sideloading. 3.  All phone vendors could be encouraged to build W10M version of their flaglships which can run both the WP native apps as well as the Android apps thru either direct download or Project Astoria app porting.  Project Islandwood won't hurt either. 4.  The early adopters automatically become the Project Astoria Preview testers.  Their experiences will provide the feedbacks to the Project Astoria team.  The Android app developers and Windows Store are not getting paid during the testing period.  This is an unsual situation they have to live with.  
  • This is not betrayal it is just part of development for porting apps from android to windows
    This will make them easy & save money
  • Really? So, to all the devs who took the time to learn how to write for WP should be thrilled? I don't think so, it takes a lot of work and time to learn this very, very specific skillset when they could have just learned to write for Android and then just ported over a cheapo app. It seems like WP users don't care where an app comes from as long as it comes from "somewhere".
  • When you get no apps and looks like nobody trusted then must understand to the final consumer, if the developers learned to Windows language why not Microsoft do an porting app from Windows phone to android and IOS respectively, is if only did Windows apps why not port my apps to android without lost the look and feel and robustness of Windows phone apps on android
  • So what's the alternative? We should be stuck with barren appstore? And ignore an innovative bridge that can still encourage coding a windows specific app because you spent time on a specific skill set? This happens all the time in various industries. Don't get me wrong I really appreciate the windows devs, but this has gone on long enough and unfortunately the status quo has been proven to be ineffective
  • If the Windows Phone apps are superior to the Android competition those developers have nothing to fear, do they? You are acting like it's the end of the world. It's not. The Windows Phone devs will just have more competition. And more competition is always a good thing for the end users. And if the platform grows as a result of this that means more customers that can buy their apps, so it's a win even for the devs. The alternative is Windows Mobile dieing. That will result in a complete loss revenue for the devs, and will be bad for consumers as well because they'll have less alternatives.
  • Is not a betray after all the same developers created the snowball, now if the people which could turn the apk to appx successfully then proves that is interest in their apps coming to Windows phone and also that although Astoria be already on alpha is a powerful tool which dev n must take seriously and get attention, now is not excuses for developers to not have available their app on Windows, even Microsoft is making easy to them port their app and giving the other check to be slapped by move their exclusive apps to the rival
  • @Daniel Rubino - thanks for the well written and balanced article.
    Also nice to see the legality highlighted which is something I've mentioned, but not seen reported.
    This really makes it in the app dev interest to port it and put it in the win store though. As most people wouldn't be bothered to sideload it themselves unless its not available in store.
  • You wrote an article about installing Windows 10 on Macs just recently now. Did you ever try Rosetta applications in OS X back in 2006 / 2007? It may sound off-topic, but it is not. The point is, Apple knew people would not buy Intel Macs when all their fav apps (like Photoshop) were custom-made for PowerPC, so the Rosetta app translation layer was developed to let PPC-only apps to run with no extra user complexity, on Intel hardware. Yes, some apps ran a lot slower. I was there, using a Macbook 1,1 model and it worked pretty good. So, what happened? Did every developer say "why bother making new universal PPC/Intel binaries? My old PPC app works fine!". No, they went out and made universal apps that were optimised and ran straight off with full performance on both platforms. Before you knew it, every critical app was converted to universal and later it ran as Intel-only. The transition was complete and Apple (and devs) have been happy ever since. So, fast forward to now and look at Microsoft: they are not in the same situation, but it is similar in some ways. Putting it short and concise: If Apple could do it, so can Microsoft. It will take a lot of time though.
  • I don't understand the betrayal bit.  Can someone explain who this technogy would hurt? It doesn't seem to enable piracy in any particular way.  If the APK is available, then it's available.  Anything being done here would be just as possible on Android proper, or Bluestacks, or DuOS, or whatever...It's like saying WINE enables piracy of Windows Apps on Linux.  You still need the app...  
  • This reminds me of hopw Blackberry 10 tried to get devs on the platform. Failed because people would rather sideload the latest app from them self rather than wait for an outdated version. Big name apps don't care for a few million users. They feel that if their platform is worthy, it should have at least 20% of the market share. I know you are going to mention Desktop here but I am speaking strictly of Android apps on other platforms. 
  • I am not a developer or programmer. This is not a criticism of anyone. It seems to me that one category of Windows Phone applications is "App Gap Fillers."
    That is, apps that provide functionality similar to popular iOs or Android apps.
    These gap filler apps may just provide a "needed" app, or may be superior to the iOs/Android app.
    It may be superior by being more constant with Windows Phone, live tile support, etc.  I feel that these gap filler apps largely exist because the iOs/Android developers have CHOSEN not to develop for Windows Phone. This choice by iOs/Android developers opened a window of opportunity (no pun intended) for the app gap fillers. The iOs/Android developers have always had the option to release a Windows Phone version their app, thus closing the window of opportunity. I can see how developers of these apps might feel that MS is making it too easy for iOs/Android competitors to compete with their apps. The Windows Phone app developers will have to compete based on the merits of their own app, not just the lack of availability of a "missing" app. The windows phone developer may win in a head to head to head comparison. The universal app model increases W10 mobile potential revenue by opening  up W10 desktop. The "bridge" technologies will help fill the app gap which MAY help W10 mobile adoption. Native W10 universal apps have the potential of being the best. Filling the app gap is good for users; hopefully it will be good for the WP developers as well.
    The rules of the game are changing.
    When one door (Window?) closes, another opens. (Pun intended.)  
  • I think most developers who work hard to make good Windows native apps will see positive affects from user's being able to compare their apps directly to Android and iOS apps in the future. I'm thinking of Rudy, who's 6tag app, I think, would stand up to anything available from iOS or Android.
  • In fact this can enhance users experiences and extend Windows Phones life. From my point of view this is something very good for all WP users...
  • Yes, does this also mean Windows mobile will have more apps than iOS and Android since Windows mobile will have Windows 10 universal apps, iOS, and Android apps?
  • Yeah, but immagine the same apps 2 times. Developers might drop development for wp app version, and that's not good
  • If a native W10 Mobile app is better, than the "bridge" iOs/Android version the developer will be "encouraged" by W10 users to continue/maintain/improve the native app. If a native W10 Mobile app is not any better, than the "bridge" iOs/Android version, what loss is it to users if the native app is dropped. Users needs will still be met by the "bridge" app.
  • It didn't worked for me :cry:
  • That's a matter of perspective.
  • Not really. Aside from already stated issues, this is not the answer for typical non technical users. They're not going to know how to do this, that it even exists. They will rely on the store.
  • Why don't Microsoft provide some incentive for developers who make native Windows apps ?
  • They already did a while ago, they paid truckload sof money for many developers to port to Windows Phone platform. It didn't work out too well. In fact, the biggest benefactory was a developer that released hundreds of crappy apps that merely replicates many of the iOS/Android apps because MS was paying per app. The reality is that incentives don't work when you don't have the users pushing you forward.
  • Welll to know the main thing is .! Apps ain't there so the platform didn't worked out to be ahuge success .!! Later when microsoft is trying to get the devs onto this .! Its becoming a one sided affair why do that when some devs making native apps .!! Microsoft is in squeeze what to do .!, basically trying to make the consumer winner here .! Maybe microsoft should make up a better incentive option for devs who are developing native apps for windowsphone than porting !! Hope so that boasts there morale XD well it will be intresting to see what happens next in future
  • They already did a while ago, they paid truckloads of money for many developers to port to Windows Phone platform. It didn't work out too well. In fact, the biggest beneficiary was a developer that released hundreds of crappy apps that merely replicates many of the iOS/Android apps because MS was paying per app. The reality is that incentives don't work when you don't have the users pushing you forward.
  • No if they make it 50/50 for native universal apps at least the first year of release vs usual30/70 for ported ones that will be surely a solid incentive
  • Mirosoft tried, they paid a number of developers a handsome amount of cash to do a WP version of their app. Mostly these developers did a basic 'it works' version, took the cash and abandoned development. No matter how much effort Microsoft puts in to this, most developers really could not care less. And I'm pretty sure some major ones are under pressure from mainly Google to not port to Windows. Google knows full well that Windows is their main competition in the long run and have been doing whatever it takes to slow down the growth of the Windows mobile ecosystem for years basically.
  • The real power of these tools is that devs can so very little work and get an app into the store. Sideloading is just an inconvenient side effect. If this is successful at getting more apps, I believe it will result in bring more users to the platform. If you get a stronger user base, they will want native apps and devs will be happy to switch to native.
  • True to a point, what most people don't realize is how much time it takes to maintain just one quality app. I could honestly never see having the time to maintain an Android app while trying to maintain a native WP app. It really is more than you think.
  • But probably those tools only works for apps of android 4,4 and not with M version and also porting doesn't mean that the entire code can't be ported, I think must be specific software that can not be ported like antiviruses, system tools, specific map system or specific systems which uses the kernel source and certain dependencies too or abilities of playback that are not present on Windows phone and Windows 10
  •   I have faith that since Win10 is on millions upon millions peoples computers and it uses some sort of APP interface. Devs, banks, companies would be jumping to make apps for Windows now. Which of course easily leads effortlessley to Win 10 Phone getting thos apps. I hope MS focuses more on Plan A rather than focusing on side loading Android Apps (expect tons of issues). I wonder if MS is able to focus on one freaking good idea.
  • Plan A is preferred, but this is a multi-pronged attack. If a dev isn't interested in plan A, there's Android porting. If they dont like that, there's iOS porting. If they dont like that, there's the new web apps extensions to make web apps behave like native.
  • In fact with android m can websites behave as apps and this thing can't be ported unless the browser supports routines of html5 or system routines triggered by web browser
  • Thats funny that wc cares but cb has made it very easy to find stuff like this for pb/bb10
  • This is so sad. People are so desperate for apps that they are willing to take scraps and hand me downs. Just when I started settling back in with windows phone and enjoying the os things like this make me so frustrated. There goes any hope of native windows app. We are the new blackberry.
  • We been the damn blackberry for years now. A phone without crucial apps including banking apps is a useless phone. When it comes to basics out of the box experience WP is great but once you download apps on IOS or Android, WP platform becomes a device for pure texting and calling.
  • My bank is there...Wells fargo.
  • My bank is there too, USAA.
  • Bank of America and Chase Bank are the 2 I used and now they are gone. Bought a second cheap Android phone so that I could do check deposits. This is BS! Everyone hates MS even the large corporations. The apps were already in the store and working. How much could it cost a large bank to update one single app?
  • the android bofa app works well using Project Astroria -- of course, the camera feature/function drops you out of the app.  
  • The camera feature is the only thing that makes an app necessary over using the web interface. No Camera to allow deposits means not useable to me.
  • This sums up my 2012-2015 experience with Windows Phone. The side load projects are great news short term for WP users but long term just deter devs from learning, promoting and using WP themselves. Hello Android.
  • For once I totally agree with you. Sideloading the apks isn't like having full developer support for a native app. Posted via the Windows Central App for Android
  • Great read. I like all articles Dan writes.
  • Yay, I can install Counter Strike Portable! But im guessing it will work with unity Android games?
  • At least some developers will be starting and testing their apps now. The sooner the better really.
  • ...untill Google does their so called "security update" which accidentally/intentionally will make apks stop working on Windows Mobile 10 :)
  • Since the core of Android is open source and Google does have to justify the breakage, this would be seem as an anti-competitive attack and could get them in trouble.
  • well blocking youtube certainly didnt....what was the justification there ?
  • It was something to do with ad revenue I believe.
  • you referring to the WP youtube app? Google was well within their legal rights to do so, though it was incredibly douchey, Microsoft made the app by reverse engineering googles site, they didn't use the API's google allows for 3rd party devs.
  • The open source part of Android really has _nothing_ to do with what you see as Android on today's phones. That is mostly closed source Google components replacing the open source parts. The Open Source part of Android has been all but abandonned by Google and in no way represents anything close to what Google now delivers as their branch of Android OS.   You might want to read THIS 
  • Yes, they have all but abandoned AOSP, well, I think they have actually. But normal people don't know this. It was amazing when I first started off, but it isn't what it used to be as you said.
  • Thanks for that link. The biggest challenge spelled out is in creating a complete alternative built-in app experience for the Google App. Win10 plus ASOP solves that problem. There are still plenty of hooks Google could put in to prevent Android apps running without Google services, but Win10 + ASOP seems to be the most credible alternative Android platform to what Google provides.
  • I would not be surprised if MS eventually starts contributing to AOSP - providing APIs to MS services as an alternative to Google Play services. If done at a big enough scale, this could be a wedge that tears Android away from Google.
  • Thats not entirely true anymore were seeing less & less open api updates as time goes by android will be closed source
  • Most of the important parts of Android, from a developer's perspective, are already closed source.
  • Already have done that by deny their applications to a platform and have almost 89% market place even have the search engine which is the used in everywhere and that is not called abuse of market position?
  • and how would thatwill work? what about BB? or what about the million sites that offer APK (legal ones) or the ones that offer it through their sites like some 3rd party stores? Stop dreaming and thinking google can do anything you can already run Android apps on a desktop or tablet... and they did nothing about it because they couldnt
  • Exactly. It would also break backwards compatibility with all of the existing Android phones.  This isn't a web or network API we are talking about.  This is the APIs that make up the runtimes on the phones.  MS has created a layer that mimics the Android runtimes.  For Google to break this, they would have to break all of the existing Android phones as well.      
  • thats good news then ! personally as a dev i really dont care...:)
  • They would not have to break Android phones. Simply update Google Play Services, anyone with an Android phone will get the update, and MS will have to build a whole new version of this service for Android developers to recompile apps over before new versions could work on Windows Phone.
  • Google play store apks do not work now as well.
  • Don't make it , it'll simply need a reset after installing the first wave of your wanted apps from android , for developers option will not work anymore
  • try to cancel dev unlock using wp8.1/wp10 sdk or do a hard reset. Also remember always turn off the developer switch before reboot/shutdown.
  • Yeah I know , a friend told me about that but after having the problem present