Reading time 11 min

As companies become more aware of the importance of web performance, internal teams begin to research tools they can use to use to track their metrics and improve the user experience of their websites and applications. One free tool has become prominent in the space – Google Lighthouse – and one question often bubbles up: “I use Google Lighthouse for one-off snapshots of my site’s performance, so why do I need a performance monitoring solution?”

However, there’s a better question that could be asked here: “When is a free tool like Google Lighthouse adequate for my business needs, and when does my company need to invest in a more robust, best-in-breed monitoring and optimization solution?

Limitations of Lighthouse

If your business is relying solely on one free tool – like Lighthouse – it’s inevitable that it will quickly bump up against some of that tool’s limitations. At that stage, the business will need to incorporate a more sophisticated performance solution with a fuller, more comprehensive suite of features that provide the information required to continuously monitor, trend, remediate, and improve performance over time. Or, in other words, this is the point when the glow of the Lighthouse can’t go all the way through the fog.

No matter the level of your business’s performance maturity, it’s critical that you take a closer look at Google Lighthouse to understand where it shines and when that light isn’t enough to help you navigate to dry land.

Where Google Lighthouse Shines Bright

Google Lighthouse has a lot going for it. It can quickly gather basic performance information about any web page (in or out of production) right in the Chrome browser through DevTools, from the command line, or as a Node module. Because it doesn’t require adding any code, you can track not only your own pages but also any competitor pages.

When you run Lighthouse, you can choose to receive up to five different scores, including SEO, Best Practices, Progressive Web App (PWA), Accessibility, and Performance, that can provide valuable insight for your dev team to act on.

The Lighthouse Performance score is based on some of the most important performance metrics: First Contentful Paint, First Meaningful Paint, Speed Index, Time to Interactive, First CPU Idle, and Estimated Input Latency. As we’ve discussed before, Lighthouse blends these performance metrics into a single composite score. This score rates a page’s performance on a scale of 0-100, making it easier to determine whether a site is “better” than a previous version – or the competition.

Google Lighthouse Scores

In addition to these scores, Lighthouse provides a list of what it calls “Opportunities” – suggestions that you can use to improve your site’s performance. It’s a high-level look at some quick fixes that you can implement.

Because Google built Lighthouse, many view it as a way to gain a peek under the hood, so to speak, at what is otherwise a secretive and proprietary set of algorithms that determine search result rankings. If the Lighthouse tool audits your site using what Google considers to be best practices, the thought process goes, then the results can help you understand how Google will view your site. This is where, even when your business has grown out of its use as your only performance tool, Lighthouse can continue to add value alongside other solutions.

So if you are a small business that is just starting out with web performance, if you have a tight budget, and if you only need to run occasional one-off audits of your performance, Lighthouse is a great place to start.

But that’s exactly it – it’s a place to start.

Google Lighthouse is a great place to start for performance analysis. It lets you quickly see what's wrong & allows you to grow into more advanced monitoring & optimization solutions as your needs mature. #webperf #perfmatters Click To Tweet

Maturity Matters: When Your Business Needs a Brighter Light

As a business grows, matures, and expands its understanding of web performance and how it can affect users and customers, the limitations of Google Lighthouse become more critical to understand and address.

When evaluating your performance solution requirements, keep in mind that:

  • Maintaining performant sites and applications requires you to efficiently gather and analyze data points over time.
  • Multi-step user flows and business transactions can often be too complex to manage manually.
  • Data granularity becomes more important as your development processes mature.
  • Detailed optimization analysis and guidance are necessary for operationalizing your performance strategy and driving time-to-market improvements.
  • Users come to your website from around the world, and it’s essential to understand how all locations – regional and global – experience your site.
  • Not everyone uses Chrome to access your website.
  • Maintaining performant sites and applications requires you to efficiently gather and analyze data points over time.

    When used out of the box, Lighthouse lets you manually run a point-in-time assessment. Eventually, you are going to need more than one data point at one moment in time to measure your performance and to monitor performance changes over days or even hours or minutes. When you reach that stage, a manual process will become time-consuming and, ultimately, impossible to keep up with.

    Plus, performance needs to be not only continually monitored but, as your business matures, also baselined and measured against itself to track not only improvements but also events with negative impacts. Even if you save your Lighthouse reports each time you run them, you’ll need to establish some sort of system so that you can compare and contrast the data, track your progress, see where things improved or got worse when changes were implemented, and more. This can quickly become unwieldy, and it also can make collaboration across teams difficult without spending even more time creating a unique system to review and monitor each individual report.

    As you outgrow the one-and-done level of performance monitoring, you’ll need to automate these assessments so you can easily acquire multiple data points. This is where a more comprehensive solution like Rigor can help.

    Rigor can be configured to automatically run as many times as you need, as often as you need to (every day, every hour, or every five minutes), for multiple web pages. Set it up, set alerts to notify users when there are anomalies, and get detailed reports about your performance metrics and the steps needed to make them better. In addition, Rigor allows you to view deep-dive reporting or to produce higher-level executive dashboards that can be shared with stakeholders who just need the basic facts about performance.

    Rigor Executive Dashboard Performance

    Even better, Rigor holds that performance data for 2 years. This allows your teams baseline, benchmark, review (including retroactively reviewing past data), report, and compare and contrast your data month-over-month or even year-over-year.

    For a mature business with performance monitoring needs that go beyond the most basic, the automation of this process can save time, money, and frustration while delivering the depth of data that is necessary to make the proper adjustments and improve the user experience.

    Multi-step user flows and business transactions can often be too complex to manage manually.

    Lighthouse is page oriented: It can analyze the performance of individual web pages. Superficially, this can seem like a reasonable way to think about performance. However, a business typically needs to think not only about how each page is performing but also about how to optimize the critical flows of the site that drive revenue or otherwise improve a business objective.

    Take an ecommerce site as an example. While the performance of the home page is important, what is even more important is the performance of the entire checkout flow – from clicking on a product page to adding a product to a cart to checking out and paying. Beyond that, a business needs to know much more than whether the flow is simply fast or slow. It needs the ability to drill down to determine which parts of a flow are causing a slowdown, which parts should be optimized and how, and where – and why – customers are abandoning their carts along the way.

    This is where a more comprehensive solution than Google Lighthouse is required. With Rigor, you can easily define a multiple page flow using the industry-standard Selenium script recorder, and then monitor that flow for performance issues. Then, you can use those insights to make improvements that will, in turn, reduce your cart abandonment rates and increase your revenue.

    Rigor - Performance of Flows

    Data granularity becomes more important as your development processes mature.

    The client base for most businesses is not all using the same device on the same network to access a website or web application. But that is the assumption that Lighthouse makes. For a high-level overview of how a site is performing, that may be adequate, but a more mature business will need to understand how to optimize their site or application for not just the top-of-the-line devices on the fastest networks but also many other variations that are older and/or slower.

    So when using Lighthouse to review how a site is performing on mobile or desktop, you’ll find that it has already chosen for you what that means – what specific device, what size, and so on. When it comes to network speed, Lighthouse gives you three options – and no others. You can review a page for “mobile” or “desktop” and “Simulated Slow 4G, 4x CPU Slowdown” or “Applied Slow 4G, 4x CPU Slowdown” or “No Throttling.”

    Lighthouse-Device and Throttling

    But what if you want to test one of your web pages on a specific device running on a different network? In his front-end performance checklist, Vitaly Friedman notes that one should “gather data on a device representative of your audience.” If you need this level of granularity of your data, you’ll need to move to a more robust solution that gives you more options – Lighthouse (out of the box) can’t do it for you.

    Does it matter? Yes, whether you’re a multinational company or your business is concentrated in a single country or area, your users’ needs will vary. Not everyone has access to a top-of-the-line device on the fastest network possible, and so you need to make sure that your application’s performance on, say, an older model Android phone on a slow connection is just as smooth as it is when viewed on the latest iPhone on 5G. And if you are able to track which specific devices and connections are used by the majority of your users, you then need a solution like Rigor that can run performance tests using those exact specifications rather than generalities.

    Detailed optimization analysis and guidance are necessary for operationalizing your performance strategy and driving time-to-market improvements.

    Lighthouse offer around 20 suggestions of ways to improve performance under the “Opportunities” label. While this is a good start, there are hundreds of best practices for optimizing web performance that aren’t checked by Lighthouse – everything from CDN configuration issues and advanced image optimizations to MP4 or WebM video optimizations. As a business matures and is tracking performance across multiple flows, they often need to check for optimization opportunities. Solutions like Rigor can test for over 300 performance best practices.

    Rigor - List of Defects

    Lighthouse provides some basic information about how to resolve different performance issues. Sadly in large organizations, not everyone can be a Google-level performance expert! Clearly communicating what an issue is, why it is important, and providing detailed steps on how the issue can be resolved are all critical to quickly optimizing your site.

    While Google and other sites like CSS Tricks have excellent advice on optimizing your performance, as companies grow they don’t want to waste time tracking down details about the current approach to implementing a best practice. Commercial solutions like Rigor take the effort off of you by centralizing and maintaining this information, as well as making it searchable by the responsible role.

    Rigor provides step-by-step instructions on how to remediate performance issues – as well as a team of experts who can step in with professional services to actually take a more hands-on approach to these fixes on an ongoing basis.

    Rigor - Step by Step Optimization

    Users come to your website from around the world, and it’s essential to understand how all locations – regional and global – experience your site.

    When you run Lighthouse, you’re getting performance information based on where you are physically sitting. For a small business in the same city as the site’s server, this may be enough information to get started.

    However, most companies do business with users who aren’t in the same location as their server, so this can quickly become a major issue when tracking performance. You can use the local data to extrapolate, but it won’t be as accurate as if you could run tests around the world, in multiple locations.

    When you need to find out how a customer across the country – or across the world – interacts with your site, you’ll need to move to a solution like Rigor. From there, you’ll be able to test your site’s performance in multiple locations – even China – and make adjustments. Viewing your data across locations and regions quickly surfaces performance issues or CDN configuration issues, as you can see in the graph below, showing the radically higher Time-To-Interactive metrics in Australia vs the United States.

    TTI from Locations

    Not everyone uses Chrome to access your website.

    Lighthouse works in Chrome – but no other browser. Chrome may own the lion’s share of the overall browser market, but take a deeper look at your user base – is everyone using Chrome? When your business grows in maturity and has a larger base of users, you’ll need to be able to monitor performance across more browsers than just Chrome. Enterprise solutions like Rigor will actually run different browsers (not merely just changing the User-Agent).

    Browser Logos
    Credit: https://github.com/alrra/browser-logos

    What About Hacking Lighthouse?

    When I talk with people about the pros of Lighthouse but also the limiting cons and limitations that a mature business will find challenging with this tool, I often hear, “But wait! It’s open source! I can wrap Lighthouse or use glue code to wire it into other utilities to enable it to do some of those things!”

    My answer is that yes, you absolutely can write code to bend Lighthouse to your unique environment and workflows. You can augment it to run on a regular cadence, or to track multiple pages, or to store the results and implement reports of progress over time.

    But I follow this up with, “What business are you in? Why does your engineering team exist?” Unless you are in the business of building a robust web performance assessment and monitoring solution, you should be spending 100% of your resources on improving your product and ultimately improving the business.

    Hacking Lighthouse takes time, energy, and resources from your team. There’s no guarantee that these hacks will work or that they will co-exist peacefully with your other code (without breaking anything). You could, instead, purchase a full, robust solution that handles everything a mature business needs, delivers product support on demand, and even does more.

    While you can hack Google Lighthouse to handle more complex monitoring tasks, is it worth your team's time & energy to do so? #webperf #perfmatters Click To Tweet

    Find a Balance: When You Reach the Lighthouse Limits, Add a Brighter Bulb

    To be clear, Lighthouse is a good open-source tool that provides many benefits. This is exactly why Rigor gathers and reports on the Lighthouse performance score!

    But understand that there are limitations to Lighthouse and that there are more mature performance-monitoring tasks that it cannot handle easily – or at all. I suggest that when you have to start spending more and more resources on a tool that doesn’t, at its core, do what you need, you have outgrown that tool.

    When your business has reached that level of performance maturity and needs more robust, more granular data to achieve its goals, it’s time to invest in a comprehensive performance solution. Look for one that can be used by multiple business units to automate performance monitoring and deliver detailed reporting and optimization insights.

    With this type of solution in place, you can focus your team’s energy on what it does best – making an awesome, compelling product – while also ensuring that they can implement the performance fixes that will enable you to give users the best experience possible (through all workflows, on all devices, across all networks, and in all locations).

    If you want a first-hand look at exactly how the Rigor platform can give you control over your performance data, take advantage of our free web performance report. For no cost or obligation, we will measure six key performance metrics for your site and analyze your site for over 300 causes of slow performance to provide you a prioritized list of optimizations you can make right now.

Suggested Blog Posts

The Perception Gap for Poor Web Performance

E-commerce revenue continues to grow,as consumers turn away from shopping in brick-and-mortar stores to shopping online.  However, many businesses are not prepared for this growth because they do not fully understand the market and how to invest in...

Read More

Using Browser Trends to Maintain a Better Site

Because of the multifarious nature of web clients today, it’s important to consider the usage statistics when designing, implementing, and managing your site. However, misconceptions often arise when determining what browsers to design...

Read More

Finding Causes of Intermittent Errors from Google Webmaster Tools

Google Webmaster Tools is a web service that allows webmasters to view the status of their sites as seen by Google and the Googlebot crawlers. In addition to indexing your site structure and content, the Googlebot crawlers also record data on perform...

Read More

Optimization Options not Always Optimal

Web designers and developers are always looking for ways to speed up their page load times. Yahoo has an excellent article written on the best practices for speeding up your page. How do you know if implementing one of their suggested practices will...

Read More