Real User Monitoring (RUM) and synthetic monitoring are two methods used to track website performance. Here’s what you need to know:
- RUM tracks real user interactions on your site, providing insights into actual user behavior, device usage, and network conditions.
- Synthetic Monitoring uses automated tests to simulate user interactions in controlled environments, measuring performance metrics like load times and uptime.
Quick Comparison
| Aspect | RUM | Synthetic Monitoring |
|---|---|---|
| Data Collection | Real user activity (passive) | Automated tests (active) |
| Environment | Real-world conditions | Controlled scenarios |
| Feedback Timeline | Continuous insights | Immediate, scheduled feedback |
| Focus | User experience metrics | System performance metrics |
| Coverage | All pages and paths | Predefined test paths |
When to Use RUM: Ideal for tracking real user behavior, geographic performance, and analyzing peak traffic periods.
When to Use Synthetic Monitoring: Best for pre-production testing, monitoring critical paths, and detecting issues during maintenance.
For the best results, combine both methods to get a complete view of your website’s performance.
Main Differences: RUM vs Synthetic
How Each Method Collects Data
RUM and synthetic monitoring gather data in completely different ways. RUM works passively, collecting data from actual user interactions through a JavaScript beacon that tracks activity in real time. On the other hand, synthetic monitoring uses automated tests to simulate user behavior in controlled environments at scheduled times .
Now, let’s look at the kind of performance metrics each method captures.
Types of Performance Data
The performance data collected by RUM and synthetic monitoring varies significantly:
| Metric Type | RUM | Synthetic Monitoring |
|---|---|---|
| User Experience | Session duration, bounce rates | Load times, availability |
| Geographic Data | Natural user distribution | Specific test locations |
| Network Conditions | Real-world variety | Simulated conditions |
| Testing Scope | All pages and paths | Predetermined scenarios |
| Update Frequency | Real-time data | Scheduled intervals |
Advantages and Drawbacks
The differences in how these methods work lead to distinct benefits and challenges for each.
RUM Advantages:
- Tracks real user experiences
- Provides geographic and demographic insights
- Collects data from a large number of users
- Connects performance metrics to business outcomes
RUM Limitations:
- Limited in-depth performance analysis
- Lacks competitive benchmarking
- JavaScript implementation may impact site performance
- Does not include detailed waterfall charts
Synthetic Monitoring Advantages:
- Establishes performance benchmarks
- Allows for competitor comparisons
- Analyzes asset loading in detail
- Can provide actionable improvement suggestions
Synthetic Monitoring Limitations:
- Focuses only on specific URLs
- Might miss problems occurring between tests
- Cannot capture real-world user conditions
- Limited to predefined geographic locations
Real User Monitoring vs Synthetic Monitoring Comparison
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When to Use Each Method
Let’s dive into when each monitoring approach makes the most sense for your needs.
When to Choose RUM
RUM works well in scenarios like these:
- Business-Critical Applications: Measure how performance affects key metrics such as conversion rates and user engagement across various devices, browsers, and network conditions .
- Peak Traffic Analysis: During high-traffic periods, RUM provides live performance insights, helping identify bottlenecks that synthetic tests might miss .
- Geographic Performance Monitoring: RUM gathers global performance data, highlighting regional differences without requiring extra test setups.
When to Choose Synthetic
Synthetic monitoring shines in these situations:
- Pre-Production Testing: Use synthetic tests in staging environments to catch performance issues before they hit production .
- Critical Path Monitoring: Keep an eye on essential user journeys and API endpoints with regular checks, such as every 15 minutes .
- Maintenance Windows: During off-hours maintenance, synthetic tests can spot configuration problems before users interact with the application .
Each method has its limits, so understanding these constraints is key.
Known Constraints
| Constraint Type | RUM | Synthetic Monitoring |
|---|---|---|
| Data Collection | Relies on live traffic, making it less effective during low-traffic periods | Focused on predefined test scenarios |
| Testing Environment | Results vary due to real-world conditions | Controlled setup may overlook real-world issues |
| Response Time | Insights arrive after actual user activity | Provides immediate feedback post-tests |
| Coverage | Captures all user paths but needs traffic | Limited to pre-configured test paths |
| Cost | Costs grow with traffic volume | Fixed costs based on test frequency |
Both methods are most effective when used together. Each compensates for the other’s gaps, offering a more complete monitoring strategy. Details on combining them are up next.
Using Both Methods Together
Combining both methods is the best way to optimize page speed, offering insights that are both proactive and real-time.
Why Use Both
RUM provides live user data, while synthetic tests simulate key scenarios in a controlled environment. Together, they create a well-rounded monitoring system.
| Benefit | Description | Impact |
|---|---|---|
| Comprehensive View | Merges real-user data with synthetic tests | Eliminates blind spots in monitoring |
| Proactive & Reactive | Identifies issues before deployment and validates real-world performance | Enables early detection and fixes |
| Better Diagnostics | Combined data highlights performance bottlenecks | Speeds up issue resolution |
| Performance Tracking | Verifies improvements through tests and user data | Builds a dependable feedback loop |
Setup and Implementation
Follow these steps to integrate insights from both methods:
-
Set Up Synthetic Tests
- Monitor critical user paths.
- Define baseline performance metrics for comparison.
-
Deploy RUM
- Measure page load times by region.
- Track user interactions and their impact on business metrics.
- Spot browser or device-specific issues.
-
Link Data Sources
- Feed monitoring data into a unified analytics dashboard.
- Cross-reference test outcomes with actual user experiences.
Success Story
OneNine improved its page load speed by 700%, bringing it down to just one second . This approach of combining RUM and synthetic testing not only confirmed performance gains but also ensured ongoing issue detection, proving the value of using both methods together.
Conclusion
Summary Points
Deciding between RUM and synthetic monitoring comes down to your specific needs and website objectives. Here’s how each approach stacks up:
| Monitoring Type | Best Used For | Key Benefits | Limitations |
|---|---|---|---|
| RUM | Tracking real user behavior and long-term trends | Provides real user data and usage insights | Requires high traffic to be effective |
| Synthetic | Proactive testing and establishing baseline metrics | Operates in a controlled environment with instant feedback | Limited to predefined scenarios |
| Combined | A full-spectrum monitoring solution | Offers a complete view of performance | More complex to implement |
Each method plays a crucial role in building a strong performance monitoring strategy. As Akamai highlights:
"RUM tools provide invaluable insight into actual user behavior and long-term trends that synthetic testing may not anticipate or test for."
OneNine Services
OneNine takes these principles and applies them by blending synthetic testing with real user monitoring into a seamless strategy. They’ve consistently helped clients achieve measurable performance gains through this integrated approach .
Their offerings include:
- Daily speed testing with rapid developer response
- Real-time performance tracking
- 10-minute average response time for addressing issues
- 24/7 technical support
