Web Application Monitoring: What To Measure and How
Performance issues in web apps are common—but even minor ones can impact your conversions, revenue and customer satisfaction. Fortunately, web application monitoring tools help you identify issues early and maintain a great user experience. Read on to discover which monitoring tools and metrics are right for you.
What Is Web Application Monitoring?
Web application monitoring means using software tools to check how your web application is performing. The goal is to ensure your app is error-free and works optimally to deliver a great user experience.
While it’s possible to check web applications manually, monitoring tools automate the process and notify you instantly when there’s an issue. The upshot is that you get alerted to issues sooner and can rectify them before customers notice anything has happened.
Application monitoring ultimately helps you:
Reduce downtime
Protect the user experience
Improve search engine rankings
Prevent security vulnerabilities from developing
How Do You Monitor a Web Application?
Monitoring a web application involves a combination of methods to capture both active and passive data about how the app is functioning and how users experience it.
Synthetic monitoring creates scripted transactions that run regularly to simulate how a user would interact. This alerts you proactively when key paths or workflows degrade.
Real user monitoring (RUM) captures actual user sessions in production—page loads, transaction times, errors, device/browser types—letting you see how real users experience your app.
Observability or digital experience intelligence (DXI) platforms tie performance data, user behaviour, error logs and business outcomes together so you not only detect issues but understand business impact, such as lost conversions due to slow checkout.
To implement monitoring, you should:
Instrument your app by adding RUM script, tying into backend logs, etc.
Define key workflows or transactions to watch
Set alert thresholds
Visualise trends over time
Tie performance data to business KPIs
By layering synthetic, real‑user and DXI approaches, you get both proactive visibility—before users complain—and reactive diagnosis—when users do complain. You then link technical issues with business metrics, such as bounce rate, conversion drop or revenue loss, to prioritise fixes.
Key Metrics for Web Application Monitoring
Web application monitoring tools track a wide range of performance metrics to ensure your app is fast, reliable and delivers a great user experience. These metrics can be measured continuously, often hundreds of times per day, to detect issues before they impact users.
Common metrics include:
Technical and Infrastructure Metrics
Application uptime: The percentage of time your app is fully operational
Network performance: Latency, packet loss and throughput affecting connectivity
Hardware utilization: CPU, memory and storage usage to ensure systems aren’t overloaded
Software performance: Response times, API performance and service availability
Errors and crashes: Frequency and severity of application failures
Internal links and dependencies: Health of internal services and third-party integrations
User- and Business-Focused Metrics
Core Web Vitals: Measures of loading speed, interactivity and visual stability
Error rates in critical workflows: Failures that directly impact user tasks or transactions
User engagement and satisfaction metrics: Bounce rate, session completion, conversion rates and task success
Throughput or request rates: Number of requests processed per second in key services
Anomalies or unusual behavior: Rare events or patterns indicating potential issues, such as security breaches or spikes in errors
Focusing on these key metrics helps you identify both technical bottlenecks and user experience problems, ensuring you can proactively maintain app performance. We’ll dive deeper into how to monitor and act on these metrics later in the blog.
Why Monitoring Your Application Is Essential
Monitoring your application is important because even the most well-developed web apps will inevitably experience performance issues. Not only are apps complex and ever-changing, but they also interact with apps from other third parties.
These third-party apps are totally outside of your control, and when they have updates (or bugs), it can have a knock-on effect on your app.
And here’s the kicker—even a small change in app performance can affect how your users engage with you. For example:
Google found that when page load times increase from one to three seconds, the bounce rate increases by 32% (bounce rate is the frequency that users leave without any further interactions).
Similarly, the BBC found that for every additional second of loading time, 10% of visitors leave their website.
Google also found that for every one-second delay in mobile load time, conversions decrease by up to 20%.
It’s clear that users are very sensitive to changes in performance. But that’s not all…
How App Performance Affects Google Search Rankings
When generating search results, Google wants to direct users to the websites that will be most helpful to them.
Because of this, Google assesses the user experience your website delivers by looking at performance metrics. It calls these metrics Core Web Vitals (CWVs), and they include things like:
Loading: How long it takes for the initial elements of your website to appear
Interactivity: How long it takes before users can perform key interactions (like clicking a menu item)
Visual stability: How much your page elements move and resize as the page loads (which is bad for user experience)
While they’re not the only thing it looks at, Core Web Vitals play an important role in how Google ranks your site. The worse your CWVs are, the more likely Google will penalize you in the search results. According to Google, “Optimizing for quality of user experience is key to the long-term success of any site on the web. Whether you're a business owner, marketer, or developer, Web Vitals can help you quantify the experience of your site and identify opportunities to improve.”
Monitoring Tools: How To Measure Web Application Performance
There are dozens of tools available for monitoring web applications. Below, we’ll look at four broad categories of monitoring tools, from free options through to advanced DXI platforms, and how you can use them to measure your web application’s performance.
1. Free Web Application Monitor Tools
- Google Page Speed Insights gives you an instant readout of your Core Web Vitals.
Pingdom tests your site and “grades” specific elements affecting its speed.
Uptrends provides continuous site monitoring with a free (if basic) plan available.
Montastic monitors your site for free and emails you if it goes down.
2. Purpose-Built Web Application Monitoring
While it’s useful to know if your app goes down, this won’t help you prevent it from happening. Accordingly, you may want to invest in a more sophisticated tool that spots warning signs earlier.
There are dozens of web application monitoring tools out there, but these are our top picks:
Site 24x7 is an all-in-one monitoring app for small and medium businesses.
Uptime is a website and application monitoring tool that lets you test your site performance from locations around the world.
Sematext synthetic monitoring offers uptime + API monitoring, website performance monitoring, SSL certificate monitoring and more.
3. Enterprise Application Performance Monitoring (APM) Platforms
APM platforms provide a comprehensive toolset for monitoring and measuring the performance of any application, including web applications. Some APM businesses refer to their products as observability platforms due to their focus on proactive problem-finding.
Dynatrace is an observability platform designed for complex cloud setups in large organizations.
Logic Monitor is an infrastructure monitoring tool for websites, networks, servers, databases and more.
IBM Instana is an observability platform for complex, modern, cloud-native applications, offering a range of monitoring tools.
4. Digital Experience Intelligence (DXI) Platforms
DXI platforms like Glassbox provide application monitoring and performance analytics for web or mobile apps.
But what’s really helpful about DXI tools is two advanced features they provide:
Real user monitoring (RUM) collects data on what real users do, then uses it to assess service-level quality delivered to them. RUM can give you many of the insights you need to deliver stand-out digital experiences. However, RUM alone is not enough to protect your revenue and reputation. A digital experience intelligence platform can help you see a complete picture of the customer journey so you can deliver a fast and effortless customer experience.
Synthetic monitoring automatically tests the paths users take through your app. It simulates user behavior—for example, by filling in your credit card application form just like a user would, while checking for errors at each step.
These features help technical teams see not just what’s going wrong, but why— and how it impacts the business.
Real-World Examples of Web Application Monitoring in Action
Organizations across industries are using digital experience intelligence and monitoring tools to improve application performance, reduce user friction and protect revenue. Marriott International, for instance, enhanced customer login and activation by leveraging a DXI platform. Working with Glassbox, the team identified a common issue affecting thousands of customers, ultimately achieving a 60% reduction in support requests.
A large UK retail bank increased conversions on its online account opening process by detecting backend errors caused by special characters in customer names. Previously, these errors caused users to drop off without any visible feedback. Using Glassbox insights, the bank was able to resolve the issue and streamline the user experience.
SoFi, a financial services provider, leveraged digital experience analytics to prevent an estimated $9 million in potential revenue loss. By monitoring user behavior and application performance, SoFi was able to identify critical bottlenecks and take corrective action before they impacted customers.
These cases demonstrate how monitoring tools combined with real user insights allow businesses to pinpoint issues, improve conversions and deliver seamless digital experiences.
Understanding Key Data From Web Application Performance Monitoring
Application performance monitoring tools are sophisticated, and most will give you an avalanche of information. Expect to see some combination of the following datasets:
Uptime means the amount of time your website is up and running (i.e. accessible to users).
Core Web Vitals track the loading speed and stability of your website or app according to Google’s standards.
Error reporting helps you track crashes, issues and errors and identify the causes behind them.
- RED is a monitoring method that focuses on checking the health of your application itself (rather than the infrastructure supporting it). For each of the services in your architecture, it measures
Rate: The number of requests the service handles per second
Errors: The number of failed requests each second
Duration: How long each request takes
- USE focuses on the health of your overall infrastructure, rather than your application. It looks at three main metrics:
Utilization: The amount of resources your system uses to work
Saturation: The amount of work that the resource is unable to service
Errors: The number of error events occurring
Website performance metrics can include Google’s Core Web Vitals relating to page load speed, along with other technical metrics like DNS load time, error rate and hardware utilization.
Anomaly detection identifies rare items, events or observations that can indicate a problem—like hacking or infrastructure errors. Generally speaking, only advanced product analytics platforms have this capability.
Setting Your Web Application Performance KPIs
Because the amount of data that web performance monitoring tools provide can be daunting, it’s best to focus on a small range of relevant KPIs. When you’re starting out, pay attention to the following:
Core Web Vitals. If you want to rank well in Google, it’s vital to monitor metrics that affect your page load time. Track CWV metrics such as Largest Contentful Paint and First Input Delay, and regularly check how any site changes affect them.
Key transactions or workflows. Set your tool to test each step in business-critical workflows, then monitor the results. For example, if you’re an insurance company, you might have a “get a quote” tool on your website. Synthetic monitoring tools can test the quote process, just like a person would, to check for errors.
Progress against historical pain points. If you’ve had repeated issues with specific metrics in the past—for example, error rates in your application—track them to see your progress over time.
Benchmark comparisons. Where industry standards are available, benchmark your website against them to monitor how you stack up against competitors. This could include performance metrics, like page load speed, or campaign-focused metrics like conversions.
How Monitoring Tools Connect App Performance To User Experience
If your business serves users through a web application, monitoring its performance isn’t just helpful: it’s a sink-or-swim activity. Performance issues are inevitable, and you have to spot them early to prevent security risks, reputation damage and user frustration.
However, the more complex your app—and the more you rely on it for revenue generation—the more you need advanced tools. When app performance is mission-critical, simple uptime monitoring is not enough. Only by using a tool that reveals how your performance KPIs affect users can you deliver an outstanding digital experience to them.
Go Beyond Web Application Monitoring With Digital Experience Intelligence
Web application monitoring and real user monitoring help you find out what’s going wrong—but it doesn’t automatically show you how to fix it. By combining your monitoring data with experience insights in Glassbox, you can link app performance to business outcomes and learn:
What’s causing the issues
How issues affect users, customers and your business overall
Which projects you need to reserve technical resources for
Find out how Glassbox can help you today.
