What is the Difference Between Synthetic and Real User Performance Testing?

Last Updated: July 25, 2024

Two primary methods are used when conducting web and application performance testing: Synthetic Performance Testing and Real User Monitoring (RUM). Each individual method offers unique insights and by understanding the differences between them, you’re able to choose which is the best approach for you and your teams. In this article, we’ll take a look into both testing types, some of their benefits, and challenges, and how they compare to help you make the best choice for optimizing your application performance.

What is Synthetic Monitoring?

Synthetic performance testing typically involves the act of simulating user interactions within your website or application which allows your teams to measure and analyze your performance metrics. These simulations are usually executed with automated scripts that mimic user behavior such as clicking through your application, loading pages, and submitting forms. Synthetic performance tests are also conducted in a controlled environment to allow for consistent and repeatable testing scenarios. The goal of synthetic performance testing is to identify as many potential performance bottlenecks as possible which you can then prioritize those fixes to ensure system stability.

Key Features of Synthetic Performance Testing

• Tests are usually run in a controlled environment with predefined conditions to ensure there is consistency across multiple test runs.
• This type of testing helps you anticipate how your system will perform under various loads.
• It also helps to provide a baseline for performance when you compare different versions of your website or application.
• Allows you to detect and fix issues earlier on in your development before they affect your real users.

Benefits and Challenges of Synthetic Performance Testing

Synthetic Performance Testing offers the significant benefit of early issue detection which allows for potential performance problems to be addressed before they impact real users. The controlled environment ensures consistency and repeatability, which is crucial for reliable benchmarking and establishing performance baselines. Additionally, synthetic tests can cover a wide range of scenarios, including those that may not frequently occur in real user interactions, ensuring comprehensive performance evaluation.

However, the realism of synthetic testing is limited, as it might not fully capture the complexity and variability of actual user behavior. Setting up and maintaining these testing environments can be resource-intensive in terms of time, effort, and costs. Furthermore, there is a risk of encountering false positives or negatives where issues detected in synthetic tests may not manifest in real-world usage or vice versa. Simulating high traffic volumes to test scalability also requires significant infrastructure, which may not always be feasible.

What is Real User Monitoring?

Real User Monitoring (RUM) is also known as Real User Performance Testing, and it involves tracking and analyzing the real user interactions within your website or application. RUM typically collects your data in real-time to help provide you with insights on how your users experience your application in a natural environment rather than a simulated environment. RUM usually aims to capture many performance metrics such as page load times, transaction completion times, error rates and more. By gathering this type of data, you’re able to understand the actual performance that is experienced by your end users, and you can make informed decisions to further improve areas of your website or application.

Key Features of Real User Performance Testing

• When data is collected from real users, it offers a clear cut and accurate reflection of your user base and experience.
• Monitoring a wide range of metrics across different devices, locations, and networks gives you more data to work with when looking to make improvements.
• With all this information, it allows for the analysis of performance based on user demographics, behavior, and other characteristics.
• This type of testing and monitoring allows your teams to continually be updated on any insights into your application performance which enables you to make future improvements.

Benefits and Challenges of Real User Performance Testing

Real User Monitoring provides the invaluable benefit of accuracy which offers an authentic view of your user experiences and highlights any real-world performance issues. This user-centric approach ensures that your performance improvements will directly enhance your user satisfaction, as it focuses on actual user interactions. The contextual data collected from different devices, browsers, and network conditions also provides a holistic view of your performance. Continuous monitoring also offers ongoing insights which supports iterative development and continuous optimization.

However, the complexity of analyzing vast amounts of real user data can be challenging and requires robust analytics tools. Additionally, since RUM identifies issues as they occur, it can be a reactive approach. This means that problems might affect users before they are resolved. Collecting user data also requires strict adherence to privacy regulations and best practices, and the variability in performance data due to diverse user environments can make it challenging to pinpoint specific issues.

Synthetic Performance Testing vs. Real User Performance Testing: Which one do you need?

Deciding between Synthetic Performance Testing and Real User Monitoring depends on your specific business needs, objectives, and resources. Here are some considerations to help you choose the right approach:

When to Choose Synthetic Performance Testing

1. Pre-Launch Testing: Synthetic performance testing is ideal for identifying issues before launching a new website or application.
2. Benchmarking: Use synthetic performance tests to establish performance benchmarks and compare different versions or configurations.
3. Load Testing: Simulate high traffic loads to ensure the application can handle peak usage.
4. Proactive Issue Detection: Identify potential performance problems before they impact real users.

When to Choose Real User Performance Testing

1. Post-Launch Monitoring: RUM is essential for understanding how real users experience your application after launch.
2. User Experience Optimization: Focus on your actual user interactions to enhance user satisfaction and engagement.
3. Contextual Performance Analysis: Analyze your performance data in the context of different devices, browsers, and network conditions.
4. Continuous Improvement: Use RUM for ongoing performance monitoring and iterative optimization.

In many cases, the best approach is to combine both synthetic and real user performance testing. Synthetic tests can be used for proactive monitoring and benchmarking, whereas real user monitoring provides continuous feedback from your actual users. This combination ensures comprehensive performance analysis and optimization which helps balance the strengths and address the limitations of each method.

Conclusion: Synthetic and RUM are Better Together

Synthetic Performance Testing and Real User Monitoring each offer unique benefits and address different aspects of performance testing. On one hand, synthetic testing provides a controlled, repeatable environment for early issue detection, benchmarking, and load testing. In contrast, RUM offers real-world insights, continuous monitoring, and user-centric performance analysis.

It’s usually not a one size fits all for many organizations in terms of which one you should use. If you leverage both approaches, your teams can achieve a holistic understanding of your application performance. From proactively identifying and addressing potential issues, and continuously optimizing the user experience, you’re able to optimize your website or application performance as you scale. Integrating synthetic tests with real user monitoring creates a robust performance testing strategy that ensures your applications are both reliable and responsive to real-world usage. This ultimately enhances user satisfaction and lets you achieve your business objectives.