How to run external, downloaded yet not installed apps on Android?

Question

I am just curious :

Some apps , usually for developers, allow to download other sample apps and execute the sample apps without installing them.

An example

Answer 1

i've talked with the developer of the devAppsDirect (website here) , and here's what he wrote:

The technology behind DevAppsDirect is called inAppSquared (www.inAppSquared.com) . In a nutshell inAppSquared allows you to turn an Android app into a plugin. This is done using only the publicly available Android API, no crazy hacking involved.

I did this by creating a new new mobile platform the same way Xamarin and Titanium are mobile platforms. The difference is inAppSquared has the same API as the Android API and once an app is ported to inAppSquared it can be run without being installed.

There are lots of possibilities for this technology. You mentioned plugins and extensions, but it could also be used for App Discovery, advertising, subscription services, A/B testing, bug fixing and much more.