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Getting started with DebugBear

This guide explains how to set up DebugBear for your website, interpret performance data, and deal with common problems.

DebugBear offers both run detailed synthetic tests in the lab or collect real user analytics from your website.

Demo Video​

See how DebugBear works and see an example of how to investigate a performance regression.

Set up lab-based URL monitoring​

DebugBear runs website tests in a controlled lab-environment. This is also called synthetic testing. DebugBear builds on top of Google's Lighthouse tool, so you also get recommendations for SEO and accessibility.

To get started, clicked the Add Website URL button.

Add website URL

All you need to do is provide a URL you want to test and configure the test environment:

  • Select a simulated test device
  • Select a test location

The standard Lighthouse test Mobile and Desktop test devices are usually a good starting point.

Pick a test location that's close to where most of your users are located.Then click Add Page.

Setting up site speed monitoring on DebugBear

To add several pages with the same test environment, you can click the Bulk Add button.

Bulk add button

Insert each URL on each line, with a space after to name the page. Then click Add Pages

Bulk pages added

DebugBear is also able to scan your website to add multiple pages at once.

Website scan example

Invite team members​

Invite the rest of your team so they can access monitoring data and get alerted to projects.

Add new members in the Teams tab or grant full account access to Admins.

Manage team members on DebugBear

Test result data: an overview​

Each DebugBear test result includes a lot of detail you can use to discuss website problems.

The Overview tab shows a high-level summary of all your site metrics.

The Web Vitals tab provides information specifically for improving Core Web Vitals, and shows Google field data from the Chrome User Experience Report (CrUX) along-side the lab results from DebugBear.

The Requests tab provides in-depth data on what happened on the network when loading your website. This includes page size and an in-depth request waterfall showing blocking requests, request prioritization, and rendering progress.

The Metrics tab contains all of the web performance metrics data for the page. A metric can be added to the trends graph to compare it's impact on other metrics.

The Lighthouse tab provides an overview and history of lighthouse scores for the page.

The Console tab shows any errors and logs that were shown in the console while running your tests.

The Experiments tab lets you try out performance optimizations and measure their impact without deploying any code.

DebugBear website overview

Real user page speed monitoring​

In addition to running lab-based tests you can also use DebugBear to collect real user web performance data. To do that you need to install an analytics script on your website.

While real-user monitoring (RUM) data is much less in-depth compared to lab results, it does have the following advantages:

  • RUM data tells you how your actual users experience your website
  • Google uses real user Core Web Vitals data as a ranking factor
  • You get a better idea of how diverse experiences on your website are (as different users will use many different devices, have a lot of variance in network speeds, and see different content when opening a page)

DebugBear real user data

Interpreting site speed data​

Start with the Web Vitals​

If you don't know where to start, taking a look at the Web Vitals data from the Chrome User Experience Report is a good start. To get the SEO benefits 75% of user experience should be "Good" according to each metric.

For Largest Contentful Paint (LCP) issues, first check what UI element is causing the LCP. Keep in mind that this can be vary for real users, for example based on the size of their device.

Then check out the waterfall view in the Requests tab – find the request causing the LCP element here. Then ask what causes it to occur too late. Are there many render-blocking script tags? If the LCP element is an image, does downloading it take a long time? Are there many preloaded resources competing for bandwidth with the LCP image?

For Cumulative Layout Shift issues check out the layout shifts table to see what content is shifting around. If the DebugBear lab data shows no layout shifts, but the CrUX data shows a lot then that might mean that layout shifts happen after user interaction.

For Interaction to Next Paint check to see how the interactive elements for your most viewed pages are scored. Are there background tasks that could be deferred that are causing input delay?

Core Web Vitals tab on DebugBear

The project overview page lists all pages along with historical metric data.

Here you can:

  • switch between the last 10 test results, daily, weekly and monthly data
  • view different metrics like Lighthouse scores and Web Vitals
  • bulk edit and group pages by clicking on the pencil icon
  • compare percentage and score differences between selected date ranges

DebugBear project overview

This screenshot show a month to month comparison of your performance data.

Date range comparison overview

Common website monitoring problems​

Here's a list of common website monitoring problems and how to address them. If you run into problems you're also welcome to contact DebugBear support.

Discrepancies between different data sources​

Different performance tools collect data in different test environments and report data in different ways.

Lab data collected with Lighthouse-based tools usually shows slower speeds than field data from real users. This is because the default Lighthouse network settings are very slow. In DebugBear you can select alternative device configurations like Mobile Fast to simulate a more realistic user experience.

Cumulative Layout Shift (CLS) is often higher in field data, as content shifts around as users scroll down the page or otherwise interact with it.

Test results will also vary between different lab environments. For example, PageSpeed Insights throttles the network in a way that can generate less accurate results. There's also variation in where test servers are located and what their CPU speeds are.

Variability and inconsistent test results​

Each speed test will generate slightly different results, depending on server response times and available network bandwidth. To reduce variability you can repeat tests several times and then select the average test result.

Run tests 3, 5, or 7 times

A/B tests or other customizations can also cause inconsistent test results. You can configure your website so that it behaves consistently, for example by detecting the DebugBear user agent or by setting a cookie when the page starts loading.

Finally, performance tests can sometimes finish too early, depending on when Lighthouse decided that the page looked complete. You can control this behavior by defining a Page Loaded Condition.

Page tests blocked by bot protection​

Sometimes the DebugBear test servers receive 403 Forbidden responses, or a 429 Too Many Requests code. In those cases you can add the IP address of the test server to a list of allowed IP addresses. Contact support to obtain a list of addresses for DebugBear servers.

Pages behind user login or Basic Auth​

If only logged-in users can access a page you can fill out a login form before running the test.

DebugBear also supports testing pages behind Basic Auth.

Noisy alerts​

You can mute notifications containing specific terms, like "gzip" or "google-analytics". You can also limit notifications to only certain pages, or disable certain types of alerts, for example in the "Performance" category.

Custom alerts

Page crashes or NO_FCP​

Especially if a slow mobile device is emulated, tests can sometimes fail for complex pages as the CPU becomes blocked or the pages takes too long to render. Tests also time out after waiting 15 seconds for the First Contentful Paint.

If you run into this you can either select a faster test device or contact support to increase the timeout.

Book a demo​

We can help you set up monitoring and give advice on how to optmize your website. Just book a call here.