Find out exactly why your React app is slow, not just that it is

Your website might be costing you customers right now, and a slow page is often the culprit even when all the official scores look fine.

The Score Says Fine. Your Customers Disagree.

There is a well-known website speed testing tool called Lighthouse. It is built into Google Chrome and used by web developers everywhere. It gives your site a score out of 100. Many business owners have been shown this score as proof that their website is performing well.

The problem is that a decent Lighthouse score can still mean a slow, frustrating experience for the person trying to book your service, buy your product, or find your phone number. The score measures what loads. It does not always explain why certain clicks feel sluggish, why a form takes a moment too long to respond, or why a page that looks loaded still is not quite ready to use.

A developer writing this week on the popular coding community Dev.to described building their own diagnostic tool specifically because Lighthouse kept telling them things were fine when they clearly were not. That gap, between what the tools report and what real users feel, is something we see constantly when we take over websites that owners thought were performing well.

Slow Websites Lose You Money Directly

This is not abstract. Google has published data showing that if a mobile page takes longer than three seconds to load, more than half of visitors leave. That is not a conversion rate problem or a marketing problem. That is your website physically driving away people who were already interested enough to click.

For a local tradesperson, a clinic, or a product-based business, the maths are straightforward. If your site gets 500 visitors a month and a quarter of them leave because something felt slow or unresponsive, you are losing 125 potential enquiries every single month. You are paying for advertising, word of mouth, and reputation to get people to your site, then handing them back to a competitor because a button took two seconds too long to react.

The sneaky part is that many website performance problems are invisible to the business owner. The site looks fine on your laptop, connected to your home broadband. It does not look fine on a phone with average signal in a town centre.

What This Means If You Recently Had a Website Built or Revamped

If your website was built using a modern framework (the kind that makes pages feel very interactive and app-like), it carries a higher risk of this exact problem. These frameworks are powerful but they can easily be built in ways that create invisible performance drag. The finished site looks polished. The developer is proud of it. And yet real users on real devices encounter small delays that, individually, feel minor but together add up to a website that feels effortful to use.

Worse, these issues can creep in over time as new content, new features, or new third-party tools get added. The site that was fast at launch may quietly degrade without anyone noticing.

What To Do About It

1. 1.Test your own site on your phone, not your office computer. Turn off the Wi-Fi and use mobile data. Try to book, buy, or enquire. Time how long it actually takes and note anything that feels even slightly sticky.

1. 1.Run a free speed test at PageSpeed Insights (pagespeed.web.dev). It is Google's public tool and it will give you a score for both desktop and mobile. The mobile score is the one that matters most for most small businesses.

1. 1.Ask your developer specifically about mobile performance on an average connection, not just the Lighthouse score. If they cannot give you a clear answer, that is useful information.

1. 1.Book a quick performance review with a web agency. At Thirty3 Labs we regularly find fixable issues in under an hour that make a measurable difference to how a site feels to use. It is usually far cheaper than the enquiries being lost every month.