Google Play and the App Store are the places where we can find all kinds of applications for Android and iOS: messaging, games, utilities, dictionaries, music, etc. Most users do not need other stores to find applications, although many times, due to the large number of banned apps and publication restrictions, it is better to bet on other stores.
Why are there other types of applications outside of Google Play and the App Store? Simply, this is because mainly, there are very strict rules that both stores establish for the apps that want to be part of them. For example, in Mountain View, red lines were drawn that developers can not cross when publishing their applications. Something that is not new, because it has already caused tensions between Google and developers.
What kind of content is banned on Google Play and App Store?
Explicit content or pornography
This restriction has been present for years, but it never hurts to remember: Google joins the side of Steve Jobs and does not want to see porn in their app store, a restriction that they comply to the letter, and this forces those applications to be distributed in APK. This rule also applies to explicit content of any kind. Reason why, for example, LiveLeak applications can not display explicit content, only being maintained in which there is no age restriction.Illegal bets and activities are also prohibited
Google does not have a great esteem for everything that has to do with bets or illegal activities of any kind. For this reason, this type of apps are prohibited, except in France, Ireland and the United Kingdom. Bets and lotteries can be difficult to manage and tend to be one of the most regulated offers in the App Store. Only include this functionality if you have completely reviewed your legal obligations in all the places where your application is available.Take special care with intellectual property
The Google search engine follows the DMCA requests to the letter, therefore, the theft of brands is not very well seen by the company. So remember, do not use brands that do not belong to you, and be careful with the names of your application. The intellectual property policy of the Apple App Store is also very strict. Make sure that your application only includes content that you have created or that you have a license to use it. On the contrary, your app will be removed from the App Store.
Keep an eye on the security, if your application handles data
If your application handles confidential user data, both the rules of Google and the App Store, make it very clear: you must ensure the security of this data. The applications must have a privacy policy that details how the user’s data is treated, as well as protecting the data with modern cryptography.Do not make payments within the application
Payments within the application can be used to monetize a job, and many developers abuse this system, but there are some lines that should not be crossed. Payments can not be used for physical products or for content that can be consumed outside that application.Do not manipulate users opinions
Some developers have tried: from not redirecting to the app store if the opinion is bad to offer discounts and functions “if you score with five stars” the application. Something strictly prohibited, and that will eliminate your application.Abusive advertising on Google Play
This is not new, but now it’s clearer than ever: Google Play takes very seriously those applications that follow abusive advertising techniques. Ads that pretend to be part of the system, redirect users to the installation of new applications and promote without requesting it through SMS messages, is forbidden. In addition, and as a curious detail, Google explicitly prohibits two techniques: display ads when the user clicks on Start and show ads when we leave the application. You should also consider those ads that are inappropriate for a particular audience of an application (adult-tone advertising in a children’s app, for example), and full-screen ads should show a simple output.Do not highlight the opinions in the description
Many developers, as a sample of what the application does, copy some positive comments and expose them in the descriptions of the applications. Google prohibits this, in addition to trying to place a keyword too many times, references to other applications or even too many details.The App stores are not a path of roses for the developers
With all this, we know that, although anyone can pay the registration fee, not everything is simple for developers. Although at first sight it does not seem like this, these standards limit, in a good way, what a developer can or can not do with your application. Encrypting data correctly can be too complicated for some developers, ad networks can play a dirty trick on affiliate developers, or users can share inappropriate content: all that can knock you out of the game. Some necessary rules, but that can be a headache, depending on the case. And the reason why many end up running away from app stores, launching their APKs on other sites without restrictions. 
