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12 Front End Metrics To Monitor During Front End Performance Monitoring

Imagine browsing an app, and suddenly, everything takes forever to load. It's frustrating, right? This is where front end monitoring tools can make a world of difference. By tracking front end metrics, developers can ensure an app runs smoothly, keeps users happy, and reduces frustration. This article will give you valuable insights into these critical metrics and how to use them to enhance your app's performance.

Alerty offers a frontend monitoring solution that helps you keep track of these essential metrics. It ensures your app performs well, giving users a seamless experience and keeping them happy.

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Table of Contents

What Is Front End Monitoring?

woman looking at computer - Front End Metrics

Frontend monitoring is all about monitoring the parts of your application that users interact with. This includes everything from the content they see and the menus they navigate to the APIs and components that face the user. 

It's your app's presentation layer. Think of it as making sure that what's on stage is running smoothly. No user wants to deal with glitches and lagging interfaces. That's where front-end monitoring comes in, ensuring a seamless user experience by tracking how things are going on the client side.

How Does This Differ from APM?

While frontend monitoring focuses on the user experience, application performance monitoring (APM) zeroes in on the communication between server and client. APM is essential, but it doesn't tell the whole story. 

Understanding how users interact with your application is crucial to delivering a good experience. That's why front-end monitoring is vital. It lets you see how users navigate your app and what might be causing them frustration. By focusing on the user experience, you can ensure your app meets their needs.

Why Should You Care About Frontend Monitoring Tools?

With the help of frontend monitoring tools, you can monitor your apps easily and in detail. These tools help you track:

  • What users are doing on your site
  • What pages they're loading
  • How long it takes for those pages to load

This information can help you identify and fix issues before they become a user problem. By using front-end monitoring tools, you can ensure your app runs smoothly and delivers a good user experience.

What Are Front End Metrics?

Frontend metrics are crucial measurements that let developers know how well a web app performs from the user's perspective. They nail down different performance aspects, such as:

  • Loading times
  • Responsiveness
  • User experience

Loading Performance: How Fast is Fast Enough?

This is all about how quickly the content loads and shows up on the screen. Think of metrics like:

  • First Contentful Paint (FCP)
  • Largest Contentful Paint (LCP)
  • Time to Interactive (TTI)

Each tells a story about the user's wait time, whether staring at a blank screen, seeing the main content, or finally interacting.

Rendering Performance: Is Your Webpage Snappy?

Rendering metrics keep tabs on how efficiently browsers process and display your webpage. You’ll want to measure things like:

These metrics help you see how smoothly your page appears and makes sure users aren’t left hanging.

Runtime Performance: Is Interactive Content Slowing You Down?

Runtime metrics focus on how quickly your JavaScript and interactive elements respond. Total Blocking Time (TBT) and First Input Delay (FID) are key. They show if your scripts are bogging down performance, a big deal for user engagement.

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12 Front End Metrics To Monitor During Front End Performance Monitoring

man working on laptop - Front End Metrics

1. Time to Interactive (TTI) - When Can Users Get Going?

Time to Interactive measures how long it takes for your page to become fully interactive. It tracks the point at which the page’s layout is stable, key elements (like fonts and buttons) are visible, and the user can interact with the UI without delay. This metric reflects the real user experience—how long they have to wait to start using the page.

2. First Input Delay (FID) - Keeping Things Snappy

FID complements TTI by focusing on input responsiveness. It measures the time between a user’s first interaction (e.g., clicking a button) and the browser’s response. 

If FID is high, users will feel a lag between their actions and the site’s response. Keeping FID low ensures a smoother, more responsive experience, especially for interactive content.

3. Largest Contentful Paint (LCP) - The Moment of Truth

LCP marks the point in the page load when the largest visible element (usually an image or block of text) has fully loaded. 

This is crucial because it gives an indication of when the page's main content becomes visible, reassuring users that the page is loading. A fast LCP (ideally under 2.5 seconds) means users can start consuming the page's content quickly.

4. Total Blocking Time (TBT) - Avoiding the Freeze

TBT helps quantify how non-interactive a page is before it becomes fully interactive. It measures the total time during which the main thread is blocked, preventing the user from interacting with the page. Lower TBT is critical for reducing any delays in user interactions, making your site feel fast and responsive.

5. Cumulative Layout Shift (CLS) - No More Jump Scares

CLS measures the visual stability of your site by tracking unexpected layout shifts during the loading process. A low CLS score indicates that the layout remains stable as the page loads, avoiding frustrating shifts that can cause users to accidentally click the wrong buttons or links.

6. Speed Index - Seeing is Believing

Speed Index tracks how quickly the contents of your page visually populate during the loading process. It’s a good indicator of how fast users perceive the page loading. The lower the Speed Index score, the better, which means the page visually renders quickly for the user.

7. CPU Time Spent - Keeping the Brain in Check

CPU Time Spent tracks how much time the main thread is occupied with rendering, scripting, and loading tasks. High CPU usage often causes lag and sluggishness, especially for sites that rely heavily on JavaScript. By monitoring CPU time, you can identify areas where the site becomes janky and fix those performance bottlenecks.

8. Component-Level CPU Costs - Finding the Greedy Culprits

Like CPU time, Component-Level CPU Costs breaks down CPU usage by individual components on the page. This allows you to see which parts of your code (e.g., specific JavaScript or UI components) are hogging the CPU. This is useful for pinpointing performance bottlenecks at a granular level.

9. FrustrationIndex - Mind the Gaps

The FrustrationIndex looks at the gaps between key loading milestones. For example, it examines how long users have to wait between seeing the page’s title and when the page becomes visually ready. Larger gaps in the timeline lead to more user frustration. 

The FrustrationIndex provides a clear indicator of how smooth or frustrating the overall loading process is for users.

10. Ad Weight Impact - Measuring the Drag

For sites that rely on ads, Ad Weight Impact measures how much the presence of ads affects performance. Ads can slow down your site significantly, so it’s useful to track their impact. By comparing the page load with and without ads, you can see how much they drag down:

  • Performance 
  • Optimize accordingly

11. Deviation Metrics - Spotting the Wild Cards

Deviation Metrics track the variability in your performance results. Large variance could indicate that certain pages or resources are difficult to measure consistently. This is important because it helps you understand whether your performance metrics are reliable or if external factors (like third-party scripts) are introducing inconsistencies.

12. Custom Metrics - Tailoring to Your Needs

Custom metrics are tailored to your business's specific needs. For instance, you might track how fast critical scripts or important user interactions occur. 

You can get creative by monitoring things like Time to First Tweet or Hero Rendering Times. Custom metrics allow you to track user-specific events that general performance metrics may not capture.

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What Are The Main Types Of Frontend Monitoring?

man looking at his pc - Front End Metrics

Frontend monitoring monitors how your website or app performs from the user's perspective. It’s like having a window into their experience, watching everything unfold in real-time. Generally, frontend monitoring takes two main forms: 

  • Proactive 
  • Reactive

Proactive Monitoring: Staying Ahead of the Game

Proactive monitoring is all about anticipation. This involves synthetic monitoring and mobile application testing, where you simulate user interactions across:

  • Different browsers
  • Devices
  • APIs

Think of it like a dress rehearsal before the big show. By catching issues early, you prevent them from ever reaching your users. It’s about fixing the cracks before anyone notices.

Reactive Monitoring: Seeing the Real Picture

Once your users are on your site, reactive monitoring takes the stage. This includes tools like:

  • Real User Monitoring (RUM)
  • Session replay

Reactive monitoring gathers real-time data on how users experience your site or app, from performance metrics to specific user behaviors. It’s like having a live feed of the action, showing you exactly where and when users hit snags, so you can smooth the way ahead.

The Power of Combining Proactive and Reactive

The most effective approach blends both proactive and reactive strategies. By using them together, you not only prevent problems before they occur but also gain valuable insights into unexpected issues your users face in real-time. This comprehensive strategy ensures your application:

  • Runs smoothly 
  • Provides the best possible experience for your users

Proactive Monitoring

Ready to catch issues before they affect your users? Discover how Alerty's free APM solution can help monitor and optimize your frontend performance today!

How Does Frontend Monitoring Work?

how it works - Front End Metrics

Frontend monitoring ensures your website or app runs smoothly by observing its performance from the user's perspective. This process involves various tools and techniques, each with its unique approach to keeping tabs on things.

Simulating User Interactions with Synthetic Tests

Proactive monitoring uses synthetic tests to predict your app's behavior under different conditions. This method involves sending simulated requests to your app from various:

  • Browsers
  • Devices
  • Locations globally

It’s like running practice drills to catch potential issues before real users experience them.

Real User Monitoring (RUM): Watching Users in Action

Reactive monitoring focuses on observing real users as they interact with your app. Real User Monitoring (RUM) captures user interactions, recording performance data like Core Web Vitals and any errors or long tasks. 

It’s like having a live feed of your users’ experiences, providing insight into how your app performs in real-world scenarios.

Session Replay: See What Your Users See

Session replay takes things further by allowing you to watch visual replays of users’ browsing sessions. You can see where they might encounter trouble, making it easier to:

  • Reproduce 
  • Troubleshoot user errors

Combining this with backend metrics and traces helps you:

  • Quickly identify the root cause of issues 
  • Fix them efficiently

Combining Techniques for a Comprehensive View

By using a mix of synthetic tests and real user data, frontend monitoring offers a complete picture of your app’s health. It’s not just about checking predetermined scenarios.

It’s about understanding how your app performs in the hands of real users, ensuring a smoother and more reliable experience for everyone.

Why Is Front End Monitoring Important?

man thinking about KPIs - Front End Metrics

Why do your favorite apps always seem to work flawlessly? Front-end monitoring is often the unsung hero behind it. By continuously monitoring your application, you can spot potential problems before they become a nuisance for users. 

This proactive approach means things like slow load times or broken features get fixed quickly. It keeps everything running smoothly, ensuring top-notch performance without a hitch.

Adapt to Change Like a Pro

Change is inevitable as your app grows and evolves. New features roll out, user behaviors shift, and updates happen. Without the right tools, it can be tough to keep up. 

Continuous monitoring helps you stay agile, adapting smoothly to ensure your application remains responsive and optimized. So, no matter how much your app changes, it won’t miss a beat.

Leverage Data for Better Decisions

Ever wish you had a crystal ball to guide your app improvements? Front-end monitoring 

provides a steady stream of data, allowing you to make informed decisions about:

  • Optimizations 
  • Enhancements

This data-driven approach lets you fine-tune your application, improving both user experience and overall performance. It’s like having a roadmap for success.

Build Trust and Loyalty with Reliable Performance

Users are likelier to stick with a brand consistently delivering a smooth and reliable experience. By ensuring your front end is always performing at its best, you foster greater confidence and trust in your brand. It’s a win-win situation, as happy users are more likely to:

  • Stay loyal 
  • Spread the word about your app

Stay Competitive in a Crowded Market

In a world where users have countless options, staying competitive is essential. Continuous insights into your front-end performance help you keep your application on par with, or even ahead of, competitors. 

This ensures that your application meets the high standards users expect, helping you maintain a strong position in the market.

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How To Check Performance Of Front End?

woman sitting on couch - Front End Metrics

Check Front End Performance with PageSpeed Insights

PageSpeed Insights is your go-to tool for a quick, reliable check on frontend performance. Just plug in your URL and get a detailed report on key metrics like Core Web Vitals. 

Lighthouse drives it, so you know you're getting accurate data. This tool is a no-brainer for anyone wanting a fast, straightforward assessment.

Get Detailed Insights with Chrome DevTools

Want to dig a little deeper? Chrome DevTools offers a more hands-on approach. Open the DevTools panel, head to the Audits tab, and run a performance test. 

This tool also uses Lighthouse but provides more granular insights. It's a lifesaver for local development, letting you fine-tune performance before going live.

Monitor SEO and Performance with Google Search Console

Google Search Console is essential for tracking your site’s SEO and performance. Add your site, and you’ll get detailed reports on:

  • Search performance 
  • Core Web Vitals

The data comes from the Chrome User Experience Report, based on real user interactions. This gives you a solid understanding of how your site performs in actual usage, not just in tests.

Dive Deep with WebPageTest.org

WebPageTest.org is perfect for those needing in-depth insights. Test your site from various locations worldwide, which is crucial for a global audience. The detailed reports show every step of the page load process, making it ideal for debugging issues affecting performance.

Optimize Ongoing Performance with GTmetrix

GTmetrix offers a comprehensive breakdown of your site’s speed with actionable recommendations for improvement. Features like Speed Visualization and a Waterfall Chart make it great for:

  • Ongoing performance monitoring 
  • Optimization

With paid options, you can even watch a video of your page load to spot issues.

Track User Experience with the Web Vitals JavaScript Library

For real-time tracking of user interactions, the Web Vitals JavaScript library is a top choice. You can monitor Core Web Vitals as users engage with your site and send the data to analytics platforms like Google Analytics. 

This helps you see how your site performs across your user base and correlate these metrics with business outcomes.

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6 Frontend Performance Monitoring Tools You Can Use

man using good tools - Front End Metrics

1. Get to Know Alerty

 Alerty is a cloud monitoring service for developers and early-stage startups, offering:

  • Application performance monitoring
  • Database monitoring
  • Incident management

It supports technologies like NextJS, React, Vue, and Node.js, helping developers identify and fix issues. 

  • Alerty monitors databases such as Supabase, PostgreSQL, and RDS
  • Tracking key metrics like CPU usage and memory consumption
  • It features quick incident management and Real User Monitoring (RUM) to optimize user experience
  • Its universal service monitoring covers dependencies like Stripe API, OpenAI, and Vercel 

Alerty uses AI to simplify setup, providing a cost-effective solution compared to competitors. It is designed for ease of use, allowing quick setup, and integrates with tools like Sentry, making it ideal for developers and small teams needing efficient, affordable monitoring. 

Catch issues before they affect your users with Alerty's free APM solution today!

2. Google Lighthouse: Your Site’s Swiss Army Knife

Google Lighthouse isn’t just a tool; it’s a game-changer for anyone looking to dig deep into their site’s performance. It’s free, open-source, and provides:

  • A comprehensive audit covering accessibility
  • SEO
  • PWA best practices

The tool delivers an overall performance score and gives actionable insights to enhance your site. Run it directly in Chrome’s DevTools, via the command line, or through its web interface. If you want to elevate your front-end, Lighthouse should be in your toolkit.

3. Sentry: More Than Just Error Tracking

Sentry is an open-source powerhouse that stands out for developers aiming to track errors and performance issues in front-end code. It goes beyond performance monitoring, helping you:

  • Identify 
  • Squash bugs that could affect users
  • Follow specific requests through your front end
  • Revealing potential performance bottlenecks. 

Sentry is a top choice for teams seeking real-time error tracking and performance insights.

4. Pingdom: Uptime and Beyond

While Pingdom is renowned for its uptime monitoring, its front-end performance capabilities shouldn’t be overlooked. Real-user monitoring (RUM) is a standout feature:

  • Tracking actual user interactions 
  • Offering detailed site speed and performance reports

Diverse Monitoring

It also provides customizable alerts and can monitor:

  • SSL certificates 
  • DNS health

This makes Pingdom a versatile tool for performance monitoring, essential for businesses wanting to ensure their site remains smooth and responsive.

5. Sematext: Comprehensive Monitoring for Devs

Sematext offers a one-stop-shop monitoring solution for front-end developers, focusing on:

  • Real-time alerts
  • Integration with major frameworks
  • Log management

It’s perfect for teams wanting a full view of site performance in production. Focusing on key metrics like page load time and Core Web Vitals, it seamlessly integrates with other tools. The unified dashboard provides a clear picture of your site’s health, encompassing logs and performance metrics alike.

6. LogRocket: Understanding User Experience

Not your typical performance monitoring tool, LogRocket offers a unique perspective on user interactions with your website. It captures user sessions, showing what users experience on your site. 

Track JavaScript errors, network requests, and performance hiccups to pinpoint issues. While primarily focused on user behavior and error tracking, LogRocket delivers valuable insights into front-end performance that can’t be ignored.

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Catch Issues Before They Affect Your Users with Alerty's Free APM Solution

So you're knee-deep in code, juggling frameworks like:

  • NextJS
  • React
  • Vue

Alerty is your trusty sidekick. It's a cloud monitoring service built for developers and early-stage startups. Think of it as your safety net, keeping an eye on application performance, databases, and incidents while you focus on building.

Deep Dive Metrics

It tracks metrics like CPU and memory usage, so you know exactly when things are getting dicey. With its quick incident management, you can swoop in and fix issues before they snowball. It’s like having a backstage pass to your app’s performance, ensuring everything runs smoothly for your users.

Database Monitoring Without the Headaches

Databases can be a real headache. Alerty monitors databases like:

  • Supabase
  • PostgreSQL
  • RDS, keeping tabs on the metrics that matter

CPU usage, memory consumption, and query performance. With this insight, you can spot potential problems before they become full-blown disasters. It’s like having a crystal ball for your database, helping you stay one step ahead.

Real User Monitoring: Make Your Users Happy

You want your app to be fast, smooth, and glitch-free. That’s where Real User Monitoring (RUM) comes in. It gives you a window into user experience, tracking metrics like load times and interactions. 

With this data, you can pinpoint bottlenecks and optimize your app. It’s all about making your users happy, and RUM gives you the tools to do just that.

Universal Service Monitoring: Keep Your Dependencies in Check

Your app relies on a web of services and APIs, from Stripe to OpenAI. If one of these dependencies goes down, it can wreak havoc on your app. 

Alerty’s universal service monitoring monitors all your dependencies so you know when something’s amiss. This way, you can fix issues before they ripple through your app and impact your users. It’s like having a safety net for your app’s ecosystem, ensuring everything runs smoothly.

AI-Powered Setup: Get Up and Running Fast

Setting up monitoring can be a real pain. But with Alerty’s AI-powered setup, you can hit the ground running. It automates the process, so you can get started in minutes, not hours. 

This way, you can focus on building, not fiddling with settings. It’s all about efficiency, and Alerty gives you the tools to monitor your app without the hassle.

Cost-Effective Solution for Developers and Small Teams

Monitoring doesn’t have to break the bank. Alerty offers a cost-effective solution for developers and small teams, giving you the monitoring tools you need without the hefty price tag. 

And with its seamless integration with tools like Sentry, you can streamline your workflow and keep everything under one roof. It’s all about efficiency and affordability, and Alerty delivers on both fronts.

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