There are a staggering number of apps added to the app stores every day, which means that any delay in getting yours to market can cost users, revenue, and competitive advantage. One of the most notorious bottlenecks in the development lifecycle is testing. The sheer number of devices, operating systems, and potential user scenarios can make mobile app testing feel like an endless marathon. Finding the right mobile testing tools to handle every possible scenario is paramount to making sure yours passes muster.

Slow feedback cycles, device fragmentation, and ballooning costs are just the tip of the iceberg when it comes to delays. According to mabl’s 2024 State of Testing in DevOps Report, almost two-thirds of mobile app teams are still relying heavily on manual testing, a practice that is not only time-consuming, but also fairly error-prone. This contributes to a frustrating reality where nearly half–a whopping 48%–of defects are caught in the final stages of development, right before teams are ready to ship new versions of their apps. This late-stage discovery of critical issues can cause costly delays, derail release schedules, and potentially damage a company's reputation if a flawed app reaches the market.

But what if there was a way to accelerate your testing, catch bugs earlier, and get your app into the hands of users faster? That's where phone emulators and simulators come in. As virtual devices, they offer an accessible alternative to traditional testing on physical hardware, enabling you to shift testing left to a place that’s earlier in the development cycle, reduce costs in both bugs and hardware, and ultimately deliver higher quality apps at a quicker pace. Here, we’ll explore how these tools can remodel your mobile testing strategy.

What are Emulators and Simulators?

Emulators and simulators replicate the behavior of various mobile devices within your development environment, so you can test your code in real-life scenarios without having to have the physical hardware to test it. The key difference lies in their approach:

  • Emulators recreate both the software and hardware of a target device, which gives you a comprehensive environment for testing your app's performance and compatibility across different configurations.
  • Simulators focus on mimicking the software behavior of a device, making them ideal for testing UI interactions, user flows, and general app functionality.

Both Android and iOS provide their own official mobile testing tools, respectively–the Android Emulator and the iOS Simulator–offering developers a convenient starting point for virtual testing. However, to truly scale your testing efforts and cover a wide range of device configurations, you’ll want to look into cloud-based device farms. These platforms offer an extensive range of virtual devices and powerful test automation features, which helps to streamline your QA process because they all live in a single place. At mabl, we’re able to streamline it by simplifying Appium.

The Power of Virtual Devices: Benefits That Accelerate Mobile Testing

Virtual devices bring a whole host of advantages to the table that can significantly transform your mobile app testing:

  • Speed: Test execution on virtual devices is significantly faster than on physical devices, plus you get near-instantaneous feedback, which allows your team to iterate faster.
  • Cost: Virtual devices eliminate the need for a large and expensive collection of physical devices, freeing up budget for other critical areas of development.
  • Scalability: Cloud-based device farms allow you to easily run tests in parallel across a vast array of virtual devices, maximizing test coverage and reducing testing time.
  • Reproducibility: Virtual environments provide consistent and controlled conditions for every test run, ensuring that test results are reliable and repeatable.
  • Shift-Left: By integrating virtual devices into your CI/CD pipeline, you can detect and address issues much earlier in the development process, which saves time and resources in the long run.
  • Enhanced Debugging: Many virtual device solutions provide advanced debugging tools, like step-through execution and network analysis, which makes it easier to pinpoint and resolve issues.

mabl: Empowering Teams to Shift Left with Confidence

mabl’s ability to be built into the CI/CD pipeline allows testing your code to happen earlier in the process, effectively shifting it left in your roadmap. With an AI-native platform that enhances these benefits, our mobile app testing solution also offers:

  • Effortless low-code test creation: An intuitive interface enables anyone on your team to create and maintain reliable tests without writing complex code. This accelerates test creation and empowers your whole team to contribute to quality.
  • Intelligent element identification: Intelligent locators create reliable tests that require minimal maintenance.
  • Cloud-powered scalability: Run tests in parallel across a wide range of virtual devices in the cloud, getting results in minutes, not hours.
  • Unified platform: Consolidate your web, API, and mobile testing efforts within a single platform, streamlining workflows and enhancing collaboration across teams.

When to Go Virtual (and When Not To): Practical Tips for Smart Testing

While virtual devices offer a lot of benefits, it's important to understand when they are the best option and when real devices are necessary. Let’s explore the different testing categories and discuss best practices:

Business critical user journeys
Verifying business-critical user journeys is arguably the most important objective a team can have. Many of these journeys often don't require hardware-specific features like cameras or connectivity modules, so they’re ideal candidates for early testing on virtual devices. Using virtual devices early in the development process, when code is coming in at high volume, allows developers to ensure their changes align with business needs without breaking the budget. As development nears a release, ensuring these tests pass on a smaller subset of real devices delivers extra peace of mind. Regardless of the type of app being built, having a critical user journey that can be tested with virtual devices early in the development cycle helps catch issues sooner and streamlines the overall testing process.

Non-business critical user journeys
Great user experiences cover all user journeys, not just the business-critical ones. It’s often overkill to run entire test suites against real devices due to cost concerns, which is where the availability and low costs of virtual devices come into play. 

UI layout consistency & accuracy
Building exceptional front-end experiences is hard but essential for delivering products that users love and trust. Using virtual devices is a great option for teams testing UI components that aren’t closely reliant on underlying hardware.

Maximizing the device grid
There are over 20,000 types of devices on the market, making compatibility testing an enormous challenge. While it's impractical to test across all these devices, ensuring quality across tens or potentially hundreds of devices is still crucial for broad compatibility. Virtual devices offer an affordable and scalable way to extend coverage across a wide range of configurations, allowing teams to efficiently identify and address compatibility issues without the cost-prohibitive maintenance of a large inventory of physical devices.

Defect reproduction
Bugs are like snowflakes, in that no two are alike and they each require specific conditions to reproduce. Virtual devices are a great place to start investigating because they are easily available, fast to spin up, and contain specific debugging tools to make troubleshooting easier.

Testing Category Virtual Devices Early in SDLC Virtual Devices Later in SDLC Real Devices Later in SDLC

Business-critical user journeys

Non-business-critical user journeys X X  
UI layout consistency & accuracy X X  
Maximizing device grid X X  
Defect reproduction (depending on defect) X X  


As this table illustrates, virtual devices shine in the early stages of development, where speed and cost efficiency are paramount. They excel at functional testing, UI validation, and regression testing. However, as you move towards later stages and need to validate hardware-specific features or complex user interactions, real devices become crucial.

To make the most of both worlds, start by leveraging the speed and scalability of virtual devices on platforms like mabl. Then, transition to targeted real-device testing to ensure your app delivers a flawless user experience across the entire spectrum of devices and environments.

Embrace the Power of Virtual Devices as a Faster, Better Mobile Testing Tool

Phone simulators and phone emulators online are no longer just nice-to-haves in mobile app testing; they are indispensable tools for accelerating development, reducing costs, and ensuring a high-quality user experience. By embracing virtual devices early and often in your testing process, you can shift left, catch bugs faster, and deliver exceptional mobile apps that delight your users.

Interested in experiencing the transformative power of virtual device testing? Try mabl free for 14 days and discover how its low-code test creation, intelligent element identification, and cloud-based scalability can revolutionize your mobile app testing workflow. Let mabl empower your team to create faster, more reliable, and more enjoyable mobile experiences.