Rethinking Front-end Error Reporting

Record and Replay for Redux apps

Understanding problems in web apps is hard. Between mysterious JavaScript errors, user-reported bugs, and issues caught in QA, there’s a constant struggle to get ahead of the problems affecting your users. And these are just the obvious issues — most bugs are never actually reported since users who have a bad experience just leave or suffer in silence.

Traditional error-reporting tools (like BugSnag, Sentry, and Rollbar) only solve part of the problem. Originally designed for logging server-side errors, they later added browser SDKs as front-end applications grew more complex. While these tools capture some useful information like stack traces and metadata, many teams find that their alerting is too noisy (too many false positives to be useful), and that they don’t capture enough context to elucidate complicated issues.

Front-end is different

Investigating front-end and backend errors are very different processes. Server-side code runs on a single platform. Often, the only state in the system that can cause hard-to-reproduce errors comes from easily logged events like database or cache queries. When an unhandled exception in server code takes place, it usually means there is a clear-cut problem that needs to be fixed.

On the front-end, things aren’t so simple. The average web application runs in over 15 different browsers, across hundreds of device types. State can be highly complex, coming from memory, local storage, local databases, service workers, and APIs. A web app must be robust to connectivity issues and cross-browser differences, and unlike the backend where exceptions are usually clear-cut, it can be tricky to gauge the impact on the frontend.

Given the frequency and diversity of errors that front-end developers see, the most important question becomes, did this affect the user? Unfortunately, looking at just a stack trace and an exception message, it’s very difficult to know. Is this a P0 crippling bug? Or maybe just a nuisance.

Answering the right questions

You never quite know how things will break. (credit:

Two years ago, we started thinking about what the perfect front-end bug report would look like. Clearly, it would collect basic information like a stack trace, metadata, and frequency histograms. But to really gauge the impact on the user, especially for hard-to-reproduce bugs, it has to let you actually see what happened.

LogRocket is our audacious attempt at doing just that — reproducing an issue as if it happened in your own browser.

It’s all in the video

At the center of a LogRocket error report is a pixel-perfect video that accurately captures what the user saw on screen. In order to do this without any performance impact, LogRocket instruments the DOM to record the HTML and CSS on the page at the time of the issue.

In addition, LogRocket records console logs, JavaScript errors, stacktraces, network requests/responses with headers + bodies, browser metadata, and custom logs. It also has deep integrations with libraries like React, Redux, and Angular to log actions and application state.

Watching the video is the fastest way to quickly know if an exception actually affected the user. And if it did, you can easily figure out what happened by reviewing network requests, logs, and application state.

User-reported bugs

When users ask for help, whether through a help desk, email, or worst of all, on Twitter — it is crucial that support and developers can quickly understand what went wrong. Unfortunately this typically means asking the user for screenshots, logs, and steps to reproduce.

With LogRocket, you can just search for a user and replay sessions where they encountered issues or asked for support. We’ve built integrations with most help desks like Intercom to let you view the user’s history directly from a chat.

Sometimes, it’s unclear if a user is just confused, or actually experiencing a bug. By reviewing the video replay, console and network logs from their session, you can easily make this distinction.

Most bugs aren’t explicit exceptions

While monitoring and fixing JavaScript exceptions is crucial to application health, the reality is that the majority of problems users experience aren’t explicit code errors and aren’t ever reported. UI glitches, slow performance, broken interfaces, and even confusing UX all negatively affect user happiness and your bottom line.

If front-end teams want to be able to ship new features quickly, they must have confidence that these issues are being proactively detected and surfaced.

Furthermore, issues of any type must be trustworthy — if there are too many false positives, alerts will simply be ignored.

Our mission: Surface all front-end problems that negatively affect users

JavaScript exceptions are just the first type of “issue” that we’ve started surfacing in LogRocket. The telemetry we’re collecting on the front-end lets us detect performance issues, broken interfaces, confusing UX, and more. We’ve started working with a select group of our customers like Reddit, Twitch, and AOL to surface these issues and will be rolling out to more customers in the next few months.

If you’re an existing LogRocket customer or want to start working with us, get in touch and you can join the beta.

Front-end is the future

The shift toward rich single page apps has undoubtedly improved both user experience quality and developer productivity. But with greater complexity comes the need for more observability. Existing tooling is not yet sufficient for teams to have confidence in the front-end code they ship.

At LogRocket, we’ve taken what we believe is a big step toward a solution — but there’s lots more work to do. If you want to help define the next generation of tooling for front-end developers, we’d love to meet you. We’re hiring 🙂

Record and Replay for Redux apps
Tools mentioned in article
Open jobs at LogRocket
Backend Services Engineer
Boston, MA
LogRocket's mission is to help engineering and product teams create excellent experiences for their customers. By recording videos of user session, along with logs and network data, LogRocket intelligently highlights UX issues and surfaces the root cause of every bug. In this role, you'll architect and build the system that processes millions of events per day for LogRocket, our service for understanding frontend issues. You'll ship enhancements to our backend within the first few weeks as you come up to speed, then take on the design, delivery, monitoring, and maintenance of entire parts of our backend stack. We recently raised a $15M Series B and are currently doubling in usage every few weeks. It's a great time to join!
  • Design a queue system that can dynamically scale to millions of events per second
  • Implement a search backend that allows users to search in real time across millions of log entries
  • Build a machine learning pipeline that automatically detects bugs in our users' apps
  • Familiarity with the state of the art in cloud technologies, including architectural principles, specific tools of the trade, and their strengths and weaknesses
  • Some experience operating applications with demanding scalability or availability requirements
  • A strong understanding of the performance, architecture, and cost of cloud systems
  • A strong collaborator who is transparent about progress on tasks, seeks feedback early and often, works effectively with the team
  • A motivated worker who delivers on engineering estimates
  • Growth Engineer
    Boston, MA
    LogRocket's mission is to help product teams create more perfect experiences for their customers. By recording videos of user sessions along with logs and network data, LogRocket intelligently highlights UX issues and surfaces the root cause of every bug. We've already attracted an elite roster of customers (such as Reddit, Bloomberg, and NBC) and recently raised a $15M Series B to continue building a world-class product and team. As the first Growth Engineer at LogRocket, you will bridge our engineering and marketing teams. You will be in charge of consolidating and visualizing data across the organization, identifying inefficiencies that can be solved by automation, and building and maintaining integrations with emerging frontend technologies to help drive product adoption. From day one at LogRocket, the Growth Engineer role will be an active contributor to our sales and marketing operations and help us fulfill our vision of improving society's interaction with software. If this sounds like a good fit, we'd love to hear from you!
  • You're a strong collaborator. You're transparent about progress on tasks, seek feedback early and often, enjoy reviewing code and having your code reviewed, and work effectively with the whole team
  • You consistently deliver on your engineering estimates
  • You're comfortable with JavaScript, CSS, HTML, and React or another modern frontend framework
  • You're comfortable working with APIs and marketing/CRM tools
  • Build a system that lets customers try LogRocket on their sites with a Chrome extension
  • Build a React hooks plugin for LogRocket
  • Enrich Salesforce data with customer usage data
  • Build a system that automatically recommends integrations for customers based on their toolset
  • Update our blog to use Gatsby as the frontend layer
  • Publish a blog post that analyzes frontend performance across our customer base
  • Developer Advocate
    Boston, MA
    Get in on the ground floor at one of Boston's top startups and help solve a huge challenge for developers: understanding customer experience. We're looking for a highly motivated technologist to join our team as a Developer Advocate and help grow the LogRocket brand. Our Developer Advocate will continue to foster LogRocket's relationships within the web development community, keeping tabs on what product teams need to improve customer experiences. Additionally, the Developer Advocate will help users understand LogRocket’s benefits and value proposition. As a Developer Advocate, you will be speaking for LogRocket, so it’s essential that you create and cultivate LogRocket's voice through all of your outbound interactions. You should be excited about talking to frontend engineers all day with the aim of creating and empowering a strong LogRocket community. 
  • Grow online communities: social/
  • Product marketing: Address common user questions with website copy, docs, and blog posts
  • Team activation: Help activate and educate high-value teams and identify potential case studies and customer references
  • Content: Working with our Content Director, you’ll contribute regularly to our editorial calendar. Topics will have a broad scope, from educational content creation (resources, tutorial), to thought leadership and some product marketing
  • Over time, help build out our developer advocate team by training and mentoring new LogRocket team members

  • Engineering background and ability to get into the nitty gritty of frontend engineering
  • Strong technical writing skills
  • Ability to move fluidly between strategy and execution
  • Experience creating and distributing content across multiple platforms
  • Excellent communicator, natural bridge-builder and conflict defuser
  • Self-motivated and organized, ability to work independently
  • Competitive salary and equity package
  • Health, dental, and vision plans
  • Unlimited vacation time and generous holiday breaks
  • Culture of learning and development
  • 401k and commuter benefits
  • Catered lunch
  • Sales Engineer
    Boston, MA
    Sales Engineer Get in on the ground floor at one of Boston's top startups and help us solve a huge challenge for developers and product teams - understanding customer experience. LogRocket is the first system that gives these teams complete visibility into their customer's experience using their web apps - through pixel-perfect replays of user sessions and clear insight into logs, errors and network activity. We've already attracted an elite roster of customers (such as Reddit, Bloomberg and NBC) and recently raised a $15M Series B to continue building a world-class product and team. If you’d like to join in on our mission of make every experience on the web as perfect as possible, while taking on massive ownership over your work and helping scale LogRocket to be a pillar in the Boston tech community - we’d love to speak with you! Summary We're looking for an experienced Sales Engineer to join our team and play a critical role in delivering LogRocket to potential customers. Using deep technical knowledge and understanding of the product, our Sales Engineers work closely with our Sales and Engineering teams to provide a world-class experience during on-boarding and throughout the sales cycle. This role provides and builds solutions that will ensure a customer's success with LogRocket on a daily basis and ultimately be a key player in driving revenue and converting prospects to customers!
  • Assist Sales and Customer Success team with initial discovery calls and customer on-boarding
  • Work closely with prospective customers to clearly communicate and demonstrate LogRocket's value proposition
  • Answer technical questions for prospective and current customers
  • Identify customer pain points and position LogRocket as a solution
  • Become an expert in LogRocket's product and technology stack
  • Lead On-Premise installations

  • 2+ years of Sales Engineer experience
  • Familiar with React, Redux, Angular, or other modern front-end frameworks
  • Experience with AWS or other cloud providers, preferred
  • Strong communication and customer service skills
  • Experience problem solving and troubleshooting in a fast-paced environment

  • Catered lunch throughout the week and a fully stocked kitchen with all your favorite snacks (healthy AND non-healthy)
  • Open vacation policy - we all work hard and take time for ourselves when we need it, no strings attached
  • Extensive Health, Dental, Vision benefits paid for by us, along with 401k and Commuter benefits
  • Generous stock options - we all get to own a piece of what we’re building
  • Regular team outings and activities (craft nights, boat cruises, excursions out of the city, and many more!)
  • Ample opportunities to learn and take on new responsibilities in a fast-paced, growth-mode startup
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