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Emulators vs Real Devices - Which Should You Use?

Emulators and real devices both have their pros and cons when it comes to app testing and development. Choosing between them depends on your specific needs and priorities. In this post, we'll do a deep dive into the key differences and help you decide when to use emulators vs real devices.
An emulator is software that mimics the hardware and OS of a physical device. It allows you to test apps without needing the actual device. Real devices provide the native experience, but emulators are faster, cheaper, and more convenient.
Here's a quick rundown of the key factors:
  • Faster testing cycles
  • Cost effective
  • Convenient environment setup
  • Limited hardware simulation
Real Devices
  • Provides native experience
  • Tests real-world hardware and OS
  • Allows testing of device-specific features
  • More configuration needed
The choice depends on your app, resources, and testing requirements. For most developers, using both emulators and real devices is ideal at different stages.

Key Differences

Let's explore the key differences in more detail:

Performance and Speed

Emulators like Android Studio's AVDs allow incredibly fast testing cycles compared to real devices. You can quickly tweak code, rerun the app, and see changes reflected immediately.
Real devices have to reboot, reload the app, and can be slow when loaded with other apps in the background. Testing iterations are much slower as a result.
Winner: Emulators
However, emulators only simulate specified hardware configs. They won't reflect real-world performance accurately, especially for graphically intensive apps.
So while emulators are faster for development, real devices are essential for performance testing.

Cost and Accessibility

Emulators are free to use with the development IDEs like Android Studio. You can spin up many different emulator configurations without any added costs.
Real devices must be physically purchased and maintained. Having a comprehensive set of different devices can get very expensive.
Winner: Emulators
However, emulators can't fully replicate the results of real-world hardware. So you still need a select set of real devices for testing.

Environment Setup and Configuration

Emulators allow you to swiftly create multiple configurations with different OS versions, screen sizes, hardware specs etc. It's easy to test across a wide range of device environments.
With real devices, you need to manually configure each one - installing your app, adjusting settings, connecting to networks etc. It's time-consuming to replicate across many devices.
Winner: Emulators
However, real devices don't need configuration. They represent real user environments accurately. Emulators still require fine-tuning to simulate real-world conditions.

Features and Capabilities

Emulators simulate hardware features like camera, GPS etc via apps and scripts. But the results won't exactly match that of the real sensors.
Physical devices showcase the native implementation of hardware and OS features. You can test device-specific capabilities that are impossible to replicate accurately in emulators.
Winner: Real Devices
However, accessing a wide range of real devices for testing niche features can be difficult. Emulators provide a faster way to simulate and quickly test across configurations.

Debugging Ability

Emulators allow debugging apps via features like port forwarding. You can access debug logs, system data, execute commands - everything needed for efficient debugging.
Debugging on real devices requires USB debugging to be enabled, drivers configured, gaining permissions etc. It involves much more setup and limitations.
Winner: Emulators
However, some bugs appear only on real devices. Emulators can't recreate the exact production environments leading to those issues.

Key Use Cases

Based on the differences, here are some recommendations on when to use emulators vs real devices:

Use Emulators For:

  • Faster development cycles and iterations
  • Testing core functionality and basic user flows
  • Simulating a wide range of device configurations
  • Replicating testing across device models
  • Debugging code and app behaviour efficiently

Use Real Devices For:

  • Evaluating real-world performance and crashes
  • Testing device-specific features like GPS, NFC etc
  • User acceptance testing in native environments
  • Exploring complex real-world bugs not seen in emulators
  • Testing apps before release or submission to app stores
Here are some emulator and real device examples for different testing scenarios:
  • Functional testing - Use both emulators and real devices. Emulators allow fast iteration during development. Real devices should validate core flows before release.
  • UI testing - Emulators first to quickly test across multiple screen sizes. Real devices to test final UI, smoothness, and feel.
  • Performance testing - Real devices are a must. Emulators don't reflect real CPU/memory constraints accurately.
  • Device-specific features - Real devices needed to test hardware-based features. Emulators can complement for quick preliminary testing.

Tips for Using Emulators and Real Devices

To get the best out of both emulators and real devices, keep these tips in mind:
For emulators:
  • Use extended controls to simulate real-world conditions like network speed, GPS location etc.
  • Reset emulator to factory settings before each test - no leftover data.
  • Disable animations and transitions to speed up testing.
  • Save device configurations to easily replicate and test.
  • Use emulator snapshots for faster restart without full reboot.
For real devices:
  • Keep devices updated to latest OS versions for accurate testing.
  • Perform regular maintenance - install/uninstall apps, restart device etc.
  • Disable unnecessary apps and features that consume resources.
  • Ensure you have debugging enabled on devices before testing.
  • Use device farms if lacking specific devices for short term access.
Emulators and real devices both have important roles to play in app testing. The key is using the right one at the right time based on your priorities.
Emulators are great for faster iterative development and debugging. But real devices are essential to test real-world performance before launch.
Ideally, utilize emulators heavily during active development. Then shift focus to real devices for user testing, acceptance testing and profiling before release.
By combining both emulators and real devices, you can maximize development speed while also releasing high-quality apps. Test intelligently by playing to the strengths of both options at different stages of your workflow.
Hope this guide gives you a firm handle on when and how to use emulators vs real devices for your needs! Let me know if you have any other questions.