Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
vu.nl/widgets/v1/js/vendors.min.js?v=e6f1d991	0.0 ms	778.3 KiB
vu.nl/assets/css/site.min.css?v=e6f1d991	0.0 ms	760.3 KiB
vu.nl/assets/js/site.min.js?v=e6f1d991	0.0 ms	568.1 KiB
vu.nl/assets/fonts/fontawesome/fa-light-300.woff2	0.0 ms	455.2 KiB
vu.nl/widgetspersonal/v1/js/vendors.min.js?v=e6f1d991	0.0 ms	442.3 KiB
vu.nl/widgetspersonal-vue3/v1/widgets.personal.vue3.js?v=e6f1d991	0.0 ms	375.5 KiB
vu.nl/widgets/v1/js/widgets.js?v=e6f1d991	0.0 ms	208.8 KiB
vu.nl/widgetspersonal/v1/js/widgets.personal.js?v=e6f1d991	0.0 ms	71.1 KiB
vu.nl/assets/js/webcomponents/header.js?v=e6f1d991	0.0 ms	48.5 KiB
vu.nl/assets/fonts/roboto/roboto-latin-500-normal.woff2	0.0 ms	15.8 KiB
vu.nl/assets/fonts/roboto/roboto-latin-700-normal.woff2	0.0 ms	15.7 KiB
vu.nl/assets/fonts/roboto/roboto-latin-300-normal.woff2	0.0 ms	15.6 KiB
vu.nl/assets/fonts/roboto/roboto-latin-400-normal.woff2	0.0 ms	15.6 KiB
vu.nl/assets/js/webcomponents/footer.js?v=e6f1d991	0.0 ms	15.2 KiB
vu.nl/assets/images/VU_placeholder_avatar_nobg.svg	0.0 ms	13.4 KiB
vu.nl/assets/images/VU-logo-nobg.svg	0.0 ms	11.6 KiB

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
vu.nl/assets/fonts/fontawesome/fa-light-300.woff2	190 ms

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:63.047 source:map[type:text value:[unattributed]]] map[reflowTime:0.785 source:map[column:51661 line:1 type:source-location url:https://vu.nl/assets/js/site.min.js?v=e6f1d991 urlProvider:network]] map[reflowTime:0.503 source:map[column:52315 line:1 type:source-location url:https://vu.nl/assets/js/site.min.js?v=e6f1d991 urlProvider:network]] map[reflowTime:0.259 source:map[column:52373 line:1 type:source-location url:https://vu.nl/assets/js/site.min.js?v=e6f1d991 urlProvider:network]] map[reflowTime:0.221 source:map[column:52437 line:1 type:source-location url:https://vu.nl/assets/js/site.min.js?v=e6f1d991 urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
Leogblokjes `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`	/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/1d10ff03-8cf5-46ae-...	180.1 KiB	165.7 KiB
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`	/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/b8825cd3-8828-4716-...	150.1 KiB	135.6 KiB
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`	/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/dfe99407-7a4c-4b1b-...	146.6 KiB	132.2 KiB
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`	/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/40ca9a48-72c1-4d65-...	126.2 KiB	111.8 KiB
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`	/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/4dea05a5-0c04-45e7-...	104.2 KiB	89.8 KiB
main.vuw-main > section.vuw-hero-container-width > div.vuw-hero-home > div.vuw-hero-home-image `main.vuw-main > section.vuw-hero-container-width > div.vuw-hero-home > div.vuw-hero-home-image`	/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/f6f9b8b9-2151-4782-...	92.7 KiB	14.6 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-5-DIV

nodeLabel: main.vuw-main > section.vuw-hero-container-width > div.vuw-hero-home > div.vuw-hero-home-image

path: 1,HTML,1,BODY,1,DIV,1,MAIN,0,SECTION,1,DIV,1,DIV

selector: main.vuw-main > section.vuw-hero-container-width > div.vuw-hero-home > div.vuw-hero-home-image

snippet: <div class="vuw-hero-home-image">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.

title: Preconnected origins

value: no origins were preconnected

description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.

title: Preconnect candidates

value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
vu.nl/assets/css/site.min.css?v=e6f1d991	760.3 KiB	3.9 s

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.1 s

URL	Time Spent
vu.nl/	1.1 s
vu.nl/nl	0.0 ms

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 3.9 s 741.5 KiB

URL	Transfer Size	Est Savings
vu.nl/assets/css/site.min.css?v=e6f1d991	759.2 KiB	741.5 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 6.4 s 1.7 MiB

URL	Transfer Size	Est Savings
vu.nl/widgets/v1/js/vendors.min.js?v=e6f1d991	776.1 KiB	494.8 KiB
vu.nl/assets/js/site.min.js?v=e6f1d991	567.2 KiB	376.4 KiB
vu.nl/widgetspersonal/v1/js/vendors.min.js?v=e6f1d991	407.7 KiB	348.9 KiB
vu.nl/widgetspersonal-vue3/v1/widgets.personal.vue3.js?v=e6f1d991	374.8 KiB	271.5 KiB
vu.nl/widgets/v1/js/widgets.js?v=e6f1d991	208.3 KiB	160.2 KiB
vu.nl/widgetspersonal/v1/js/widgets.personal.js?v=e6f1d991	70.8 KiB	51.4 KiB

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	777 ms
Style & Layout	481 ms
Other	421 ms
Script Parsing & Compilation	282 ms
Rendering	106 ms
Parse HTML & CSS	104 ms
Garbage Collection	21 ms

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
vu.nl/widgets/v1/js/vendors.min.js?v=e6f1d991	778.3 KiB
vu.nl/assets/css/site.min.css?v=e6f1d991	760.3 KiB
vu.nl/assets/js/site.min.js?v=e6f1d991	568.1 KiB
vu.nl/assets/fonts/fontawesome/fa-light-300.woff2	455.2 KiB
vu.nl/widgetspersonal/v1/js/vendors.min.js?v=e6f1d991	442.3 KiB
vu.nl/widgetspersonal-vue3/v1/widgets.personal.vue3.js?v=e6f1d991	375.5 KiB
vu.nl/widgets/v1/js/widgets.js?v=e6f1d991	208.8 KiB
/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/1d10ff03-8cf5-46ae-...	180.4 KiB
vu.nl/nl	155.2 KiB
/d8b6f1f5-816c-005b-1dc1-e363dd7ce9a5/b8825cd3-8828-4716-...	150.6 KiB

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits

●Optimize DOM size

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●JavaScript execution time 1.0 s

●Avoid long main-thread tasks 8 long tasks found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 80 ms

●Server Backend Latencies 120 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 90 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○User Timing marks and measures

○Avoid non-composited animations

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Names and labels

When a button doesn't have an accessible name, screen readers announce it as "button", making it unusable for users who rely on screen readers. Learn how to make buttons more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div > button `div > button`
div > button `div > button`

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`

Form elements without effective labels can create frustrating experiences for screen reader users. Learn more about the `select` element.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Alle categorieën Promoties Voorlichting & informatiesessies Cursussen Workshop … `div.cell > div.grid-x > div.cell > select#category-filter-b69a785e-1004-447b-848a-caf6759efdcd`
Datum April 2026 Mei 2026 Juni 2026 Juli 2026 Augustus 2026 September 2026 Okto… `div.cell > div.grid-x > div.cell > select#date-filter-b69a785e-1004-447b-848a-caf6759efdcd`

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div > a `div > a`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Leven in de wereld die we delen `div.grid-x > a.vuw-card-hover > div.vuw-text-left > h3.vuw-h2-light`

These are opportunities to improve the legibility of your content.

Tables and lists

Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
section > ul `section > ul`
section > ul `section > ul`
section > ul `section > ul`
section > ul `section > ul`
nav > ul `nav > ul`

Screen readers require list items (`<li>`) to be contained within a parent `<ul>`, `<ol>` or `<menu>` to be announced properly. Learn more about proper list structure.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`
li `li`

These are opportunities to improve the experience of reading tabular or list data using assistive technology, like a screen reader.

○Interactive controls are keyboard focusable

○Interactive elements indicate their purpose and state

○The page has a logical tab order

○Visual order on the page follows DOM order

○User focus is not accidentally trapped in a region

○The user's focus is directed to new content added to the page

○HTML5 landmark elements are used to improve navigation

○Offscreen content is hidden from assistive technology

○Custom controls have associated labels

○Custom controls have ARIA roles

●`[aria-*]` attributes match their roles

●`[aria-hidden="true"]` is not present on the document `<body>`

●`[aria-*]` attributes have valid values

●`[aria-*]` attributes are valid and not misspelled

●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.

●ARIA attributes are used as specified for the element's role

●`[aria-hidden="true"]` elements do not contain focusable descendents

●Elements use only permitted ARIA attributes

●Document has a `<title>` element

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●No element has a `[tabindex]` value greater than 0

●Touch targets have sufficient size and spacing.

●Heading elements appear in a sequentially-descending order

●Document has a main landmark.

●Identical links have the same purpose.

○`[accesskey]` values are unique

○`button`, `link`, and `menuitem` elements have accessible names

○Deprecated ARIA roles were not used

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○ARIA input fields have accessible names

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○`[role]`s have all required `[aria-*]` attributes

○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.

○`[role]`s are contained by their required parent element

○`[role]` values are valid

○Elements with the `role=text` attribute do not have focusable descendents.

○ARIA toggle fields have accessible names

○ARIA `tooltip` elements have accessible names

○ARIA `treeitem` elements have accessible names

○The page contains a heading, skip link, or landmark region

○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.

○Definition list items are wrapped in `<dl>` elements

○ARIA IDs are unique

○No form fields have multiple labels

○`<frame>` or `<iframe>` elements have a title

○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.

○Input buttons have discernible text.

○`<input type="image">` elements have `[alt]` text

○Form elements have associated labels

○Links are distinguishable without relying on color.

○The document does not use `<meta http-equiv="refresh">`

○`<object>` elements have alternate text

○Skip links are focusable.

○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.

○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.

○`[lang]` attributes have a valid value

○`<video>` elements contain a `<track>` element with `[kind="captions"]`

○Tables have different content in the summary attribute and `<caption>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

○Image elements do not have `[alt]` attributes that are redundant text.

○Elements with visible text labels have matching accessible names.

○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.

○`<td>` elements in a large `<table>` have one or more table headers.

100

Best Practices

General

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Map URL
vu.nl/assets/js/site.min.js?v=e6f1d991
vu.nl/widgetspersonal/v1/js/widgets.personal.js?v=e6f1d991	vu.nl/widgetspersonal/v1/js/widgets.personal.js.map
vu.nl/widgetspersonal/v1/js/vendors.min.js?v=e6f1d991	vu.nl/widgetspersonal/v1/js/vendors.min.js.map
vu.nl/widgets/v1/js/widgets.js?v=e6f1d991	vu.nl/widgets/v1/js/widgets.js.map
vu.nl/widgets/v1/js/vendors.min.js?v=e6f1d991	vu.nl/widgets/v1/js/vendors.min.js.map

●Uses HTTPS

●Avoids deprecated APIs

●Avoids third-party cookies

●Allows users to paste into input fields

●Avoids requesting the geolocation permission on page load

●Avoids requesting the notification permission on page load

●Displays images with correct aspect ratio

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●No browser errors logged to the console

●No issues in the `Issues` panel in Chrome Devtools

●Ensure CSP is effective against XSS attacks

●Use a strong HSTS policy

●Ensure proper origin isolation with COOP

●Mitigate DOM-based XSS with Trusted Types

●Detected JavaScript libraries

○Redirects HTTP traffic to HTTPS

○Mitigate clickjacking with XFO or CSP

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`
div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit `div.grid-x > div.cell > div.vuw-ratio-4-3 > img.vuw-image-coverfit`

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid

●Page isn’t blocked from indexing

●Document has a `<title>` element

●Document has a meta description

●Page has successful HTTP status code

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`