Web Vitals
Understand your application's performance score and how each web vital contributes to it. Drill in to explore opportunities to improve your app's overall performance.
This feature is available only if your organization is on a Business or Enterprise plan.
Web vitals are a set of metrics that measure the quality of the user experience on a web page. To learn more about these metrics, see Web Vitals Concepts.
For your instrumented web apps, Sentry gathers web vitals from real user traffic through supported browsers. These web vitals are used to calculate a Performance Score for your web application. Using these metrics, we surface the pages that have the most opportunity to improve your app's overall performance.
The gif below walks through how to get insights on your web vitals.
The Web Vitals page, nested under the Insights tab, gives you an overview of your page load and interaction performance for the selected project(s). You can use this page as a starting point to investigate poor Web Vitals affecting your web application and drill down to better understand which pages are affecting your web performance the most.
In the top left, the Performance Score ring shows the overall performance rating of your application. Each component of the ring represents a single Web Vital and its relative weight and impact on the Performance Score. The area chart on the right shows you a breakdown - by Web Vitals - of your performance score over time.
Below this, you can see your application's p75 vital values and the individual scores for each Web Vital. These metrics can help you prioritize which Web Vitals need attention most. Click on a Web Vital to open a more detailed summary of that metric and see which pages have the most opportunity for improvement.
At the bottom of the Web Vitals page, a sortable table shows a list of your application's pages, along with their associated p75 values for each Web Vital. Each page also has its own individual Performance Score. The Opportunity column displays a page score's potential improvement to your application's overall Performance Score if maximized to 100. The search bar above this table allows you to filter for specific pages by route name.
The Web Vitals page only displays data from your application's initial page load transactions and interactions. Navigations are not included.
From the table in Web Vitals or a Web Vital Summary panel, click on a page to open its Page Overview. Here, you can see a summary of that single page's Web Vitals. In Page Overview, you can further drill down to a specific page load sample Event, Interaction, Replay, or Profile.
The Page Overview page displays a "Page Loads" chart in the right sidebar of the page. A mini Aggregate Span Waterfall is also displayed in the right sidebar, which shows you common span paths that your application's page may take. Click the "View Full Waterfall" button or the "Aggregate Spans" tab at the top of the page to see the full Aggregate Span Waterfall.
The samples list only shows page loads with web vitals and performance score. If a page load is missing a required web vital, it will not be shown in the samples list. Find out which web vitals are required in the Browser Support table.
At the center of the Page Overview, Web Vital p75 values and scores are displayed. Clicking a Web Vital score will open a slideout panel containing a variety of Page Load samples with good to poor scores. Each sample contains an Event ID that can be clicked to open the Trace View page for further investigation. If there is a Replay or Profile associated with the sample page load, links will be included in the associated table columns.
Performance Score is a rating from 0 to 100 that summarizes the perceived performance of your web application. Page loads and Interactions on your web application are scored based on their Web Vitals. Each Web Vital is given a rating from 0 to 100 through a Log-Normal Distribution, which is then weighed and aggregated by page and overall for your entire web application.
The overall Performance Score of your web application is the weighted average of your Page Load and Interaction scores. If your web application has far more Page Load scores than Interaction scores, your overall Performance Score will be biased towards Page Loads, and vice versa. An equal number of Page Load and Interaction scores produces an overall Performance Score comprised of a 50/50 average.
Performance Scores are currently only supported on desktop web browsers.
A Page Load Performance Score is comprised of up to 4 individual Web Vital components found on each event. The default weights and score rating thresholds for each Web Vital can be found in the table below.
| Page Load Web Vital | Good (90+) | Meh (50+) | Weight |
|---|---|---|---|
| Largest Contentful Paint (LCP) | 1200ms | 2400ms | ~42% |
| Cumulative Layout Shift (CLS) | 0.1 | 0.25 | ~22% |
| First Contentful Paint (FCP) | 900ms | 1600ms | ~22% |
| Time To First Byte (TTFB) | 200ms | 400ms | ~14% |
These thresholds are meant to match Google Lighthouse as closely as possible, but there may be some differences because Sentry operates on real user data, whereas Google Lighthouse operates on lab data.
Some browsers may not support all Web Vitals used in Sentry's Performance Score calculation, so weights are dynamically adjusted depending on which ones are available on the browser.
Find out which Web Vitals are required to calculate Page Load Performance Scores in the Browser Support table.
An Interaction Performance Score is based off a single Web Vital component, INP (Interaction to Next Paint). The following table shows the score rating thresholds for INPs.
| Interaction Web Vital | Good (90+) | Meh (50+) | Weight |
|---|---|---|---|
| Interaction to Next Paint (INP) | 200ms | 500ms | 100% |
For an interaction to be considered an INP candidate, it must have a latency of at least 40ms.
Opportunity scores are number values associated with each page and are meant to give you a sense of which pages are most valuable to improve. The Opportunity score is the maximum possible increase to your application's overall Performance Score if you were to raise a page's score to 100. If a page in your application already has a score of 100, the Opportunity score would be 0, since there's no way to further optimize this page.
Opportunity score calculation is also weighted based on the traffic that a page sees. Pages with high traffic tend to have higher Opportunity scores. For example, a page with a score of 70 that experiences 1000 page loads a day will have a higher Opportunity score than a page with a score of 50 that experiences only 10 page loads a day.
Web Vitals and Performance Scores are automatically captured by Sentry's JavaScript SDKs through the BrowserTracing integration.
You can find out how to set up Sentry on your web application in the installation docs. If you are using a JavaScript framework, you may need to follow additional setup instructions for your specific framework:
Although Sentry provides auto instrumentation for many frontend frameworks, there are some environments and scenarios that may not be fully supported. If you are unable to find your pages in the Web Vitals page, check to see if your page loads are meeting the following conditions:
- Performance Scores only support Chrome, Firefox, Safari, Opera, and Edge desktop browsers. Mobile browsers are NOT supported.
- A page load must capture a minimum set of web vitals in order to be eligible for Performance Score calculation. For example, Chrome page loads must contain LCP, FCP, CLS, and TTFB; otherwise they will not appear in the Web Vitals page.
- This requirement varies depending on the client browser. Find out the full list of required web vitals in the Browser Support table.
- Some web vitals may not be captured as frequently depending on the unique behavior of your web page or your user's browser.
Our documentation is open source and available on GitHub. Your contributions are welcome, whether fixing a typo (drat!) or suggesting an update ("yeah, this would be better").