Synthetic Monitoring vs Real User Monitoring: Why You Need Both

Your users expect nothing less than perfection: lightning-fast speeds, seamless interactions, and a flawlessly responsive digital experience at every click. But as your website or application grows in complexity, are you truly seeing what your customers see? Are you able to anticipate performance bottlenecks before they hit? Guessing won't cut it when the stakes are this high, and every minor hitch can lead to frustrating experiences and significant losses to your bottom line.

This is where Synthetic Monitoring and Real User Monitoring (RUM) become indispensable. These two powerful approaches serve as your essential eyes and ears into digital performance, yet they operate on fundamentally different principles and reveal distinct types of insights.

Let's strip away the technical complexity and clearly define what sets these two vital monitoring techniques apart. More importantly, we'll prove why, for comprehensive visibility and a truly resilient digital presence, you simply can't afford to choose just one; leveraging both is crucial for delivering an exceptional and reliable user experience.

Real User Monitoring (RUM): A Brief Recap

Real User Monitoring (RUM) is a powerful performance monitoring process designed to capture and analyze every single user interaction within your digital products. Unlike synthetic monitoring, RUM provides granular, real-world data, offering invaluable insights into how actual users experience your application. This includes capturing critical load actions such as navigation start, request start, and speed index.

How Real User Monitoring (RUM) Works

A "user session," often referred to as a click path, represents the complete sequence of actions a user takes within your application. RUM diligently collects data on each individual action within these sessions, including their completion times. By doing so, it helps identify common user patterns and pinpoint specific areas where performance can be optimized. This comprehensive data empowers development teams to fine-tune high-value interaction sequences, ensuring a smoother and more efficient user journey. Ideally, RUM aims to record all user actions for a complete and accurate picture, though some less scalable solutions may sample data.

Read — RUM 101: Understanding Real User Monitoring for Website Performance

What is Synthetic Monitoring?

While Real User Monitoring (RUM) offers invaluable insights into actual user experiences, Synthetic Monitoring provides a crucial proactive approach to application performance. This method tests and monitors applications and systems by simulating user interactions through pre-defined scripts. These scripts are meticulously designed to mimic real user behavior, allowing for the evaluation of response times, error rates, and a variety of other critical performance metrics.

Synthetic Monitoring: A Proactive Approach

Synthetic monitoring essentially emulates the paths users might take when engaging with an application. It leverages scripts to generate simulated user behavior across different scenarios, geographic locations, device types, and other variables. This proactive nature allows developers to identify and troubleshoot potential issues even before an application is released. Once in production, IT operations teams can utilize synthetic monitoring to consistently and repeatably monitor critical user journeys, ensuring their stability and performance.

A key distinction from RUM is that synthetic monitoring does not require human users; it can be completely automated and run on a schedule. This automation is a significant advantage, enabling teams to detect issues, trigger alerts, and optimize system performance well before real users encounter any problems. The ultimate result is a superior end product and a significantly improved experience for your users.

How does Synthetic Monitoring work?

Synthetic monitoring operates on the principle of proactive emulation, essentially using automated "robot clients" (also known as agents or probes) to simulate user interactions with your application. This methodical approach allows you to identify potential performance issues before they impact real users.

The process typically involves a series of well-defined steps to ensure accurate and valuable data collection:

1. Script Development: These scripts are the blueprint for synthetic tests, designed to mimic a wide array of potential user behaviors such as filling out forms, clicking buttons, logging in, making purchases, or browsing web pages. Each script defines the specific activities to be performed and their sequence, capturing every step of the simulated user experience.

2. Configuration and Customization: Once the scripts are complete, you configure the monitoring parameters to reflect your specific testing needs. This involves defining where and how the scripted transactions will be executed. You can specify the geographic locations from which these tests should run, the types of devices or browsers they should simulate, and even the network conditions they should reproduce.

3. Script Execution: With the parameters set, the synthetic monitoring tool begins executing the scripts according to your chosen configuration. These automated tests send requests to your targeted system, effectively acting as "bots" that continuously test the website performance and availability of your online services. While manual synthetic testing is possible, automated execution is far more scalable and efficient.

4. Data Collection and Analysis: The monitoring software collects a wealth of performance metrics, such as response times, page load times, error rates, transaction success rates, and overall uptime. This collected data is then meticulously analyzed to identify network bottlenecks, anomalies, and other areas that may require improvement. Dashboards and ongoing reports are generated to analyze performance trends, helping teams spot patterns, troubleshoot bottlenecks, and plan for future scalability.

5. Alerting and Optimization: If any collected metric exceeds predefined thresholds, it indicates a potential performance issue or other problem. In such cases, the synthetic monitoring tool will immediately generate alerts, notifying you about the issue. Following the identification of issues, the monitoring system or the application itself can be updated or tweaked to improve web performance and other critical metrics. Another round of synthetic tests is then run to confirm that the changes have resolved the issue and that the system now meets performance requirements.

By consistently running these automated tests, especially after any application updates, synthetic monitoring provides invaluable confidence that new deployments haven't introduced any availability or performance issues.

Synthetic Monitoring vs Real User Monitoring: Key Differences

Both Synthetic Monitoring and RUM are essential for robust website and application performance management. They're highly complementary, offering different, yet equally valuable, insights.

Here's a quick overview of their core differences:

Synthetic Monitoring vs. Real User Monitoring (RUM): A Comparison

Advantages and Limitations of Synthetic and Real User Monitoring

Synthetic Monitoring

Advantages:

• Proactive Problem Solving: Identify and resolve issues before they impact users, making it ideal for pre-production testing and quicker fixes.
• Consistent Testing Environment: Get reliable and repeatable results in a controlled setting, which is perfect for benchmarking and comparing performance over time.
• Tailored Scenarios: Simulate specific user journeys and test critical functionalities to ensure everything works as expected.

Limitations:

• Simulated Environment: Synthetic monitoring might not fully replicate the vast diversity of real-world user environments and behaviors.
• Ongoing Script Maintenance: Test scripts require regular updates as your website evolves to remain effective.

Real User Monitoring (RUM)

Advantages:

• Authentic User Insights: RUM captures genuine user experiences across a wide range of devices, browsers, networks, and locations. This means you see exactly how real users interact with your site.
• Deep Behavioral Understanding: Get comprehensive details on user behavior, including Core Web Vitals, page load times, and how users navigate through your site.
• Effortless Scalability: RUM automatically adjusts to changes in traffic, ensuring you get valuable insights whether you have a few users or millions.

Limitations:

• Reactive Issue Detection: RUM can only identify problems after they've already affected your real users.
• Traffic Dependence: To generate meaningful insights, RUM requires a sufficient volume of user traffic.

To conclude, both Synthetic Monitoring and RUM offer distinct yet valuable perspectives on your application's performance and user experience. While each has its unique strengths and limitations, the most powerful insights emerge not from choosing one over the other, but from strategically integrating both.

The next section will delve into how these two monitoring approaches can work together synergistically to provide a truly comprehensive and proactive performance strategy.

Synthetic Monitoring and Real User Monitoring: Working Together

While each offers invaluable insights on its own, their true power is unlocked when used in concert. This final section will delve into how these distinct yet complementary approaches can be strategically combined to create a comprehensive, proactive, and deeply insightful performance monitoring strategy, ensuring optimal user experience and business success.

Synthetic Monitoring and Real User Monitoring (RUM): Better Together

In conclusion, while Synthetic Monitoring and RUM each offer distinct advantages, their combined application provides an unparalleled, holistic view of your digital performance. By strategically leveraging proactive, controlled insights from synthetic tests alongside authentic, real-world data from RUM, organizations can achieve true full-stack observability.

Observability platforms like TrueWatch are designed precisely for this purpose, offering both Synthetic Monitoring and RUM capabilities within a unified platform. This integration empowers teams to gain comprehensive insights, optimize performance proactively, and ultimately deliver superior digital experiences to their users.