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For frontend developers, building cool apps for the web is fun. At least, that’s the case most of the time. Imagine a scenario where you’ve fleshed out your reusable components and written unit or integration tests that passed successfully. But, suddenly, your website is down. While writing tests is a good software development practice designed to help you find bugs in your web app, it doesn’t eliminate bugs completely. Many developers are familiar with debugging applications before rolling out changes to production, but at the same time, monitoring an application’s performance while in production is equally important. By providing visibility into your web apps, frontend monitoring enables you to identify and resolve errors swiftly, so you can concentrate on developing and improving your app, rather than fixing bugs or dealing with upset customers. Frontend monitoring also helps you troubleshoot errors without reproducing them, which gives you insight with minimal effort.

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What Is Frontend Monitoring?

Frontend monitoring refers to all the processes and tools used to track and maintain the performance of an app’s client-side application. It is a subset of application performance monitoring (APM) and focuses only on the interface the user sees and interacts with. Frontend monitoring aims to ensure that all the services and systems you require for your client-side rendering are up and running when needed. These systems include API calls, interactions, and content rendering lifecycles. Monitoring your frontend systems can prevent customer dissatisfaction and revenue loss due to downtime and poor UX. In addition, frontend monitoring seeks to keep your app available and functional by managing and notifying you of errors and performance and user experience issues.

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5 Tools for Frontend Monitoring

A frontend monitoring tool usually checks for network request issues, JavaScript errors, user experience bugs like rage clicks, and general performance issues. It helps you better understand your application, what works and what doesn’t, how users interact with it, and what their experience flows are. Here are five of our favorite frontend monitoring tools that perform the functions above. They can also cater to the needs of your business regardless of its size.

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LaunchDarkly

“We’ve been using LaunchDarkly since its very early days. We first started using it as a cheaper alternative to Fullstory, but it’s been great to see the product evolve over the past few months into something much more useful — that helps blend the customer experience with debugging tools. Next.js support is also a big plus!” —Product Hunt reviewer LaunchDarkly is a frontend monitoring tool that helps engineering teams accurately reproduce, replay, and troubleshoot customer issues. With LaunchDarkly, teams can better understand their application by simulating end-to-end user sessions. Pros: Supports your favorite frontend frameworks and enables team communication. Through its high-fidelity session replay, LaunchDarkly provides all the information you need to troubleshoot errors, including the contents of your browser developer tools. Cons: LaunchDarkly currently supports React.js, Gatsby.js, Next.js, and Vue.js. Therefore, using HTML SDK to implement apps created with other frameworks like Ember.js may take a little more work.

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Sentry

“Sentry does a great job of exposing errors in your application and, perhaps more importantly, makes it really easy to track down and debug the errors. It also integrates well with your git hosting client to let you know when you introduce a regression and exactly what release it came from.” —G2 reviewer Sentry offers frontend monitoring for engineers who want to monitor and respond to bugs as soon as they happen. It alerts you when your application crashes or runs slowly and provides data about your app’s performance, allowing you to delve down into the areas that need your attention. As a result, you can address the problem that would have otherwise resulted in an error. Pros: Offers email and Slack integrations for notifications and supports a variety of framework integrations for your web application. Cons: Sentry focuses on stack traces and server-side error monitoring and doesn’t let you replay what a user did to cause the error.

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Rollbar

“[I like how] easy and simple [Rollbar] is to use! Its integration with Slack is amazing. I don’t have to constantly look at my e-mail or the website. I can just go about my workday and check the Slack channel whenever there’s an error reported. It also keeps the rest of the team informed of what’s happening.” —G2 reviewer Rollbar leverages version control systems to detect errors with recent deployments. It also transforms these issues into tickets and assigns them to whoever is responsible for resolving them. With Rollbar’s real-time error stream, developers can manage problems at low starting frequencies that are otherwise impossible to notice. Furthermore, it offers AI-powered procedures that enable developers to correct errors as soon as they occur before users are affected. Pros: Allows developers to prioritize effectively and fix bugs in real time. It also provides all information associated with the bug and groups all similar errors together. Cons: There is not enough context about your bugs. Large RQL queries may yield a slow response.

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Site24x7

“My overall experience with Site 24x7 is way better than I expected. For the cost of the services I was a little hesitant as I incorrectly assumed it wouldn’t be that great. While the interface isn’t the prettiest, it does exactly what it’s supposed to and then some. Support is great, they come up with the fixes/patches with any odd situation I run into as it relates to monitoring.” —Gartner reviewer Site24x7 is a tool for availability and user experience monitoring. It allows you to set up monitors for your websites or APIs. These monitors will then send requests to the resource you configured to gather data on its availability, response time, downtimes, etc. More than frontend monitoring, Site24x7 offers many incredible capabilities, including server monitoring, cloud management, and real user monitoring (RUM). Pros: Offers real user monitoring that enables you to examine and analyze your web app’s performance by browser and location. Cons: Provides limited integrations for frontend frameworks.

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Pingdom

_“We use SolarWinds Pingdom to monitor all our websites and applications including SAS and on-prem ones, and we are satisfied with the features and capabilities of the product. It is very useful to detect any downtime and outages as soon as it happens to be able to identify the root cause and resolve the issue very quickly.” —Gartner reviewer Pingdom sells itself as a “simplified end-user experience monitoring” that helps you test your app’s development performance and troubleshoot production bugs. Pingdom uses a programmable alerting mechanism to notify you when an app is down. With Pingdom’s uptime monitoring view, you can find out how long it takes for a page or resource to load fully. If an error occurs, you can then use its incident reports manager to go into the transaction and find the problem’s source. Pros: Offers real-time monitoring, uptime monitoring, and page speed monitoring. Cons: No grouping of alerts, and depending on the configurations you want for your monitoring, Pingdom can be expensive.

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Spend Less Time Fixing Bugs and More Time Building

Sorting messy and unstructured logs to troubleshoot errors can be overwhelming. But now that we’ve reviewed frontend monitoring tools to gain greater visibility into your web application’s client-side systems, you can free up resources to build rather than scrambling around to fix issues. LaunchDarkly can help provide you with the insight you need to fix bugs in real-time. So, feel free to explore what we do and how we do it.