Software Development

Simulators vs Emulators vs Real Devices | Mobile Testing Differences

Mobile testing involves spotting bugs in a mobile application and fixing them – ranging from identifying sign-up issues, breaking in the payment process, or finding glitches in navigation before it hits the market. This testing can be done manually or with automation, and utilizing the right testing strategy helps meet all quality and usability requirements. Among the elements necessary for a seamless testing process is the selection of the right mobile testing devices. There are 2 main types of devices for testing: real testing devices and virtual testing devices (emulator and simulator)

What Is a Real Testing Device?

Real testing devices are actual handsets used by end-users outside the testing environment.

For the purpose of testing, the team usually acquires mobile devices in great variety in models, OS, OS versions, screen sizes, etc. Testing on these devices also allows testers to check the functionality and behavioral pattern of the application.

Some of the advantages of real testing devices

  • Testing on real devices is more reliable because it allows testers to test almost all possible real-time scenarios.
  • Real testing devices can easily simulate battery issues, incoming interrupts, exact color, and brightness displays.
  • It also lets testers carry out usability testing such as the color resolution of the screen, looks, and feel of the application.

Some of the disadvantages of real testing devices

  • Real testing devices are costly
  • Due to the wide variety of handsets to work with, testing on real devices can be challenging, especially when teams are working on a tight timeframe.

What Is a Virtual Testing Device?

A virtual testing device is a software program on the computer which gives the same functionality as a real device. They are used to simulate the essential features of an actual device. Unlike real device testing, virtual testing devices are cost-efficient, but it cannot replace real devices in terms of accuracy and consistency it provides in testing. They cannot mimic the overall features of a real device such as battery life, push-up notifications, etc.

There are two main types of virtual devices: simulators and emulators.


Simulators are virtual testing software built for different operating systems for a specific purpose. They are basically made for iOS devices (iPhone and iPad) since they are not like Android devices, which are easy to emulate. The iOS simulator imitates the iOS and runs the required application within the environment by taking charge of the computer’s operating system.
Besides, iOS simulators work on macOS only because the simulator needs Apple’s native Cocoa API (a library of frameworks to handle GUI, runtime, and other operations). Therefore, testers must use either MacBook or virtualized macOS on their systems. Also, these simulators cannot imitate hardware, and some functionalities (battery state, motion sensor, and cellular interrupts) cannot be tested with it.


Emulators are virtual testing software on a computer that imitates both the software and hardware configuration of a mobile device or another computer. It works on an ISA (Instruction Set Architecture), which is written in machine language that the processor understands. The emulator imitates the target (mobile device) processor by translating its ISA into the one used by the system through the binary translation process. This helps the computer to create a reliable virtual testing environment.

Some examples of the widely used emulators for testing are Android emulators, iPhone emulators, etc. Emulators are also making moves in the mobile cloud testing field with the availability of cloud-based android devices.

Some of the advantages of virtual testing devices

  • Virtual testing devices make different testing applications on various mobile devices much more accessible.
  • In most cases, virtual devices are free software that can be downloaded via the internet for testing mobile applications.
  • Virtual devices are easier to test when testers are not sure of the mobile devices to choose from among the wide variety available, or when they are working on a budget or deadline related.

Some of the disadvantages of virtual testing devices

  • Virtual devices may generate both false positive and false negative results, which will have a negative impact on the organizations’ ROI.
  • Although they mimic real devices, they cannot cover all its features such as push-up notifications, battery, camera, etc.
  • Results obtained from testing on virtual devices may not be as accurate as expected.

Real Device Capabilities vs Virtual Device Capabilities

When to Use: Real Testing Device or Virtual Testing Device

Both real devices and virtual devices offer dynamic features, making them suitable for one phase of testing than the other. When applied to mobile application testing the appropriate way, these testing devices can help organizations meet their requirements. The best practice for use are:

Initial phase of testing

Virtual devices can be considered suitable for the beginning of the testing process. They offer a better debugging facility to speed up the testing cycle of the application. In addition, virtual testing devices are cost-effective compared to buying new smartphones. They allow testers to test their application on a wide variety of handsets using different mobile networks around the world.

The final phase of testing

For testing the application before release, real testing devices are the best options. It provides more accurate results by allowing testers to check every possible scenario in the testing cycle. Therefore performance testing, network feasibility, smoke testing, interoperability, sanity testing, and a large part of regression testing should be done on real devices.

Explore more about mobile test automation.


Mobile testing continues to increase in importance due to the significant role mobile applications play in our everyday lives. Although it requires much testing to reach the stated objectives, one of the ways to achieve that is by choosing the right tools (real devices, simulator, and emulator). However, combining these tools is the best way to create an excellent testing solution, whereby you can save cost, time, and obtain a better ROI.

Published on Java Code Geeks with permission by Katalon, partner at our JCG program. See the original article here: Simulators vs Emulators vs Real Devices | Mobile Testing Differences

Opinions expressed by Java Code Geeks contributors are their own.


Katalon is a leading provider in software test automation solutions. The company provides an affordable, flexible, and scalable testing platform for web, API, mobile, and desktop testing — from creating tests, execution, reports, to seamless integration with the CI/CD ecosystem. Learn more at
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