Real User Monitoring (RUM) vs. Synthetic Monitoring: Understanding Best Practices
For modern engineering and DevOps teams, user experience isn’t a post-deployment concern, it’s a critical operational metric. Monitoring how real users interact with your application is no longer optional, especially in high-traffic, dynamic, or global environments. This is where real user monitoring (RUM) proves indispensable. But RUM isn’t the only approach. To understand where it excels and where synthetic monitoring might be a better fit, let’s unpack both, and explore when and how to use each.
In this comprehensive guide, we’ll cover:
What Is Real User Monitoring (RUM)?
Real User Monitoring (RUM) is a type of passive monitoring that tracks actual user interactions within a website or application. It captures data from real sessions to understand how pages load, how long users stay on each page, what devices and browsers they use, and whether they face any latency, UI glitches, or JavaScript errors.
Real User Monitoring (RUM) uses browser instrumentation (usually via a JavaScript snippet) to collect this data in real-time, transmitting it to a backend for visualization, alerting, and analysis.
What Real User Monitoring (RUM) Captures:
- Page load time (first paint, DOM content loaded, etc.)
- Core Web Vitals (Largest Contentful Paint, First Input Delay, Cumulative Layout Shift)
- Geographical distribution of users
- Network performance issues (CDN latency, DNS resolution time, etc.)
- JavaScript errors and crashes
Benefits and Challenges of Real User Monitoring (RUM)
Benefits:
- Real-World Performance Insight: RUM reflects true end-user environments like networks, locations, devices, and behaviours.
- Granular Diagnostics: Know exactly where, when, and why performance degradation happens.
- User-Centric Analytics: Understand friction points that impact conversions or retention.
- Session Replay: Watch anonymized user sessions to debug UI/UX issues faster.
- Compliance & SLAs: Monitor adherence to SLAs for specific regions or browser types.
Challenges:
- Reactive Nature: Since it's based on actual user behaviour, it won't catch issues until users are affected.
- Privacy Concerns: Sensitive environments may require anonymization or careful data handling.
- Requires Traffic: No users, no data. RUM has limited value in low-traffic or pre-production environments.
Real-World Use Cases of Real User Monitoring (RUM)
- E-Commerce Optimization: Track Core Web Vitals for global users to reduce cart abandonment.
- Media Platforms: Identify buffering issues or playback failures on specific ISPs or devices.
- SaaS Applications: Understand feature adoption, UX bottlenecks, and error patterns by user role or segment.
- Fintech & Banking: Trace latency spikes or dropped transactions by geo-location.
Drawbacks of Real User Monitoring (RUM)
- Doesn’t simulate hypothetical scenarios or future traffic surges.
- Not suitable for early-phase testing or capacity planning.
- Requires historical data to detect trends, which may delay root cause identification in a new deployment.
What Is Synthetic Monitoring?
Synthetic Monitoring (also known as uptime monitoring) simulates user behaviour by scripting requests and running them from pre-defined locations at regular intervals. These synthetic checks allow you to test how your site or application behaves under specific, controlled conditions.
What Synthetic Monitoring Captures:
- Availability and uptime from multiple regions
- Response time for APIs or transactions
- Page performance across browsers and devices
- TLS certificate health, DNS resolution, etc.
Benefits and Challenges of Synthetic Monitoring
Benefits:
- Proactive Monitoring: Detect issues before actual users are impacted.
- Controlled Conditions: Baseline performance by eliminating user-driven variability.
- Pre-Launch Testing: Validate performance in staging environments.
- Global Perspective: Run tests from various geographic locations for CDN and edge testing.
Challenges:
- Lack of Real-World Context: Doesn’t capture real network congestion, device limitations, or actual user behaviour.
- Script Maintenance: Synthetic tests need constant upkeep to reflect UI or backend changes.
- False Positives/Negatives: A perfectly scripted test might not reveal UX issues that frustrate users.
Real-World Use Cases of Synthetic Monitoring
- API Performance Monitoring: Schedule automated tests for critical endpoints.
- SLA Validation: Confirm uptime and performance thresholds are met.
- Geo-Based Testing: Compare app responsiveness in India vs. US vs. EU.
- Checkout Flow Testing: Simulate a buyer journey to validate UX paths.
Drawbacks of Synthetic Monitoring
- Doesn’t account for actual user conditions like slow networks or flaky devices.
- Can’t track how different users interact with the same feature in various ways.
- May miss edge cases unless scripts are extremely comprehensive.
RUM vs. Synthetic Monitoring: Feature-Based Comparison
| Feature | Real User Monitoring (RUM) | Synthetic Monitoring |
|---|---|---|
| Data Source | Captures actual user sessions across devices, locations, and browsers. | Simulates user behaviour using scripted checks from controlled environments. |
| Proactive Issue Detection | Reactive in nature. Detects issues after users experience them. | Proactively identifies issues before users encounter them via scheduled test runs. |
| Debugging & Troubleshooting | Offers detailed insights into frontend errors, load times, and user paths. | Useful for confirming uptime and API health but lacks real session depth. |
| Usability & UX Visibility | Shows how users interact with pages, including click behaviour and engagement. | Cannot reflect true usability; follows predefined scripts with no real interaction. |
| Pre-Production Testing | Not applicable since it depends on real user activity in live environments. | Ideal for QA and staging; helps test workflows before go-live. |
| Traffic Requirements | Requires actual traffic to provide insights. | Functions even without real users, running synthetic checks 24/7. |
| Customization & Flexibility | Minimal setup with auto-captured metrics. No scripting needed. | Fully customizable but requires script maintenance as app behaviour changes. |
| Security & Privacy Risks | Involves real user data, so requires GDPR compliance and anonymization practices. | Operates without exposing personal data, thus low on compliance risks. |
| Global Visibility | Performance is shown based on actual user geography and device usage. | Can simulate access from multiple locations and networks for coverage benchmarking. |
How RUM and Synthetic Complement One Another
When combined, Real User Monitoring (RUM) and synthetic monitoring give you a full view of your app’s performance. Here’s how they complement each other:
Correlating Business with Performance
- Synthetic alerts you to outages; Real User Monitoring (RUM) shows how those outages affect user behaviour and conversion rates.
Identify Problems Before Active Users Arrive
- Synthetic tests detect regressions or bottlenecks in CI/CD pipelines before reaching production.
Testing Applications in a Staging Environment
- Synthetic simulates traffic in staging; Real User Monitoring (RUM) validates performance in production.
Troubleshooting Outages
- Synthetic can confirm whether issues are global or regional; Real User Monitoring (RUM) pinpoints the specific users and scenarios affected.
What Type of Monitoring Do You Need?
Choose your monitoring strategy based on environment, goals, and stage of development:
- If you want early alerts, uptime checks, and pre-launch validations: Go with synthetic.
- If you want user insights, real-time troubleshooting, and conversion optimization: RUM is essential.
- If you want comprehensive visibility from staging to production: Use both. Together, they close the loop on monitoring blind spots.
Why Atatus is the Best Solution Available in the Market?
Atatus offers a developer-friendly, full-spectrum observability platform with real user and synthetic monitoring built-in. Unlike heavyweight tools that require months of onboarding or dedicated teams, Atatus is designed for fast-moving teams that want answers, not dashboards.
With Atatus Real User Monitoring (RUM), you can:
- Capture and analyze every real user session without impacting app performance
- Monitor Core Web Vitals at scale and correlate them with user retention
- Trace errors and latency back to the exact browser, region, or device
With Synthetic Monitoring, Atatus enables:
- Global uptime and performance tests on schedule or on-demand
- Scripted multi-step transaction checks that emulate real user journeys
- Comprehensive health checks for APIs, CDNs, and third-party services
Whether you're operating a consumer-facing app or a mission-critical internal dashboard, Atatus delivers actionable insights in real-time without overcomplicating your toolchain.
Ready to See It in Action?
Request a demo today or Start our free trial to learn how Atatus helps DevOps, SREs, and developers gain true observability with minimal effort and maximum clarity.
FAQs on Real User Monitoring (RUM) and Synthetic Monitoring
What are the main benefits of real user monitoring (RUM) for DevOps teams?
Real User Monitoring (RUM) provides real-world insights into performance issues, user behaviour, and UX friction, helping DevOps teams prioritize fixes based on actual user impact.
When should I use real user monitoring (RUM) instead of synthetic monitoring?
Use Real User Monitoring (RUM) in production environments when you need insights into real user experiences, browser-specific bugs, or performance across different devices and networks.
Can I use both real user monitoring (RUM) and synthetic monitoring together?
Yes, combining both offers full visibility for synthetic monitoring catches issues proactively, while Real User Monitoring (RUM) shows how those issues affect actual users in real-world environments.
Does synthetic monitoring help in staging or pre-release environments?
Absolutely. Since it doesn’t rely on real users, synthetic monitoring is perfect for simulating traffic and testing features before deployment.
How does Atatus handle both Real User Monitoring (RUM) and synthetic monitoring?
Atatus provides integrated support for both Real User Monitoring (RUM) and synthetic monitoring, enabling teams to capture real user sessions and run scripted checks globally making it ideal for performance monitoring across the full stack.
Which monitoring strategy is right for my application?
Use synthetic monitoring for proactive alerts and testing, RUM for real user insights, or both to cover all stages from development to production in your monitoring strategy.
Can synthetic monitoring replace real user monitoring (RUM)?
No. Synthetic helps identify issues proactively, but Real User Monitoring (RUM) shows how real users are actually impacted by frontend errors, latency, or downtime.
What kind of data does synthetic monitoring collect?
Synthetic tools collect data like uptime, response times, transaction steps, DNS lookup time, and API latency from scheduled test scripts.
Why is Atatus a better choice for Real User Monitoring (RUM) and synthetic monitoring?
Atatus is lightweight, developer-friendly, and offers unified visibility into real user experiences and synthetic test results - all in one place.