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
www.julialang.org/assets/infra/world_map.webp	600.0 s	367.9 KiB
www.julialang.org/assets/infra/lorenz.gif	600.0 s	190.5 KiB
cdn.jsdelivr.net/gh/cormullion/juliamono-webfonts/JuliaMono-Bold.woff2	604800.0 s	997.8 KiB
cdn.jsdelivr.net/gh/cormullion/juliamono-webfonts/JuliaMono-Regular.woff2	604800.0 s	997.4 KiB
www.julialang.org/assets/infra/cartpole.webp	600.0 s	69.1 KiB
i.ytimg.com/vi/3Ocgztq05lo/sddefault.jpg	7200.0 s	48.3 KiB
i.ytimg.com/vi/wPFPT-Ech2c/sddefault.jpg	7200.0 s	47.0 KiB
www.julialang.org/libs/bootstrap/bootstrap.min.css	600.0 s	31.3 KiB
www.julialang.org/assets/infra/parallel-prefix.webp	600.0 s	25.9 KiB
www.julialang.org/libs/bootstrap/bootstrap.bundle.min.js	600.0 s	23.7 KiB
www.julialang.org/libs/highlight/highlight.min.js	600.0 s	17.4 KiB
www.julialang.org/assets/infra/backsplash-min-0.5.svg	600.0 s	14.4 KiB
www.julialang.org/assets/infra/minesweeper.webp	600.0 s	14.4 KiB
www.julialang.org/css/app.css	600.0 s	8.2 KiB
www.julialang.org/libs/buttons.js	600.0 s	6.9 KiB
www.julialang.org/assets/infra/logo.svg	600.0 s	2.7 KiB
www.julialang.org/assets/infra/juliacon_logo.svg	600.0 s	2.1 KiB
www.julialang.org/css/franklin.css	600.0 s	1.7 KiB
www.julialang.org/libs/detectdark.js	600.0 s	1.2 KiB
www.julialang.org/libs/carousel.js	600.0 s	1.0 KiB
www.julialang.org/libs/highlight/github.min.css	600.0 s	737 B
www.julialang.org/libs/youtube-player.js	600.0 s	701 B
www.julialang.org/css/juliamono.css	600.0 s	659 B
static.doubleclick.net/instream/ad_status.js	900.0 s	495 B

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
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2	40 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:30.289 source:map[column:787 line:0 type:source-location url:https://plausible.io/js/script.js 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
body > div#juliacon-videos > picture.juliacon-world-map > img `body > div#juliacon-videos > picture.juliacon-world-map > img`	www.julialang.org/assets/infra/world_map.webp	367.5 KiB	359.5 KiB
Lorenz Attractor visualization `div#tab-sci > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/lorenz.gif	190.0 KiB	111.3 KiB
cartpole reinforcement learning problem visualization `div#tab-math > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/cartpole.webp	68.9 KiB	53.6 KiB
minesweeper gameover `div.container > div#ecosystem-tab-content > div#tab-general > img.pb-2`	www.julialang.org/assets/infra/minesweeper.webp	14.3 KiB	12.9 KiB
parallel prefix graphical result `div#tab-computing > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/parallel-prefix.webp	25.7 KiB	12.5 KiB

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

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

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
www.julialang.org/css/app.css	8.2 KiB
www.julialang.org/libs/bootstrap/bootstrap.min.css	31.3 KiB	602 ms
www.julialang.org/css/franklin.css	1.7 KiB	150 ms
www.julialang.org/libs/detectdark.js	1.2 KiB

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

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: 150 ms 29.2 KiB

URL	Transfer Size	Est Savings
www.julialang.org/libs/bootstrap/bootstrap.min.css	31.1 KiB	29.2 KiB

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
cdn.jsdelivr.net/gh/cormullion/juliamono-webfonts/JuliaMono-Bold.woff2	997.8 KiB
cdn.jsdelivr.net/gh/cormullion/juliamono-webfonts/JuliaMono-Regular.woff2	997.4 KiB
www.youtube.com/s/player/57fefa84/player_embed_es6.vflset/en_US/base.js	433.2 KiB
www.julialang.org/assets/infra/world_map.webp	367.9 KiB
/s/_/ytembeds/_/js/k=ytembeds.base.en_US.I-saIP3mOa8.2021...	329.1 KiB
www.julialang.org/assets/infra/lorenz.gif	190.5 KiB
/embed/?list=PLP8iPy9hna6SZOq4EH_nE_BFulBAKXkf1&listType=...	73.0 KiB
www.julialang.org/assets/infra/cartpole.webp	69.1 KiB
www.youtube.com/s/player/57fefa84/www-player.css	57.0 KiB
i.ytimg.com/vi/3Ocgztq05lo/sddefault.jpg	48.3 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL
minesweeper gameover `div.container > div#ecosystem-tab-content > div#tab-general > img.pb-2`	www.julialang.org/assets/infra/minesweeper.webp
parallel prefix graphical result `div#tab-computing > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/parallel-prefix.webp
cartpole reinforcement learning problem visualization `div#tab-math > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/cartpole.webp
Lorenz Attractor visualization `div#tab-sci > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/lorenz.gif
Visualization of weighted data changing as more data is plotted `div#tab-ds > div.row > div.col-lg-12 > img.pb-2`
Visualization of waves in 3D, as a heatmap, and on the x y axis `div.row > div.col-lg-12 > div.container > img.pb-2`

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

●Layout shift culprits

●Document request latency

●Optimize DOM size

●LCP breakdown

●LCP request discovery

●Modern HTTP

●Optimize viewport for mobile

●Max Potential First Input Delay 20 ms

●Minify CSS

●Minify JavaScript

●Reduce unused JavaScript

●JavaScript execution time 0.1 s

●Minimizes main-thread work 1.2 s

●Avoid long main-thread tasks 3 long tasks found

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 40 ms

●Server Backend Latencies 420 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Avoid multiple page redirects

●Initial server response time was short Root document took 0 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.

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
JuliaCon Global 2026 `div.alert > p.text-center > span.alert-text > a`
juliacon.org/2026 `div.alert > p.text-center > span.alert-text > a`
Watch JuliaCon 2025 ↓ `div.alert > p.text-center > span.alert-text > a.watch-videos-link`
julia> `div.code-showcase > pre.code-content > code.language-julia > span.repl-prompt`
julia> `div.code-showcase > pre.code-content > code.language-julia > span.repl-prompt`
julia> `div.code-showcase > pre.code-content > code.language-julia > span.repl-prompt`
julia> `div.code-showcase > pre.code-content > code.language-julia > span.repl-prompt`

These are opportunities to improve the legibility of your content.

Navigation

Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. Learn more about heading order.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Fast `div.container > div.row > div.col-lg-4 > h3`

These are opportunities to improve keyboard navigation in your application.

Best practices

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Go to slide 1 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 2 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 3 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 4 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 5 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 6 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 7 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 8 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 9 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 10 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 11 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 12 `body > div.container > div.carousel-dots > button.carousel-dot`
Go to slide 13 `body > div.container > div.carousel-dots > button.carousel-dot`
Governance `div.row > ul > li > a`
Publications `div.row > ul > li > a`
Stewards `div.row > ul > li > a`
Diversity `div.row > ul > li > a`
JuliaCon `div.row > ul > li > a`

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html `html`

These items highlight common accessibility best practices.

○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>`

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

●`[role]` values are valid

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

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

●Buttons have an accessible name

●Image elements have `[alt]` attributes

●`[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

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

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

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

●Links are distinguishable without relying on color.

●Links have a discernible name

●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

●Elements with visible text labels have matching accessible names.

○`[accesskey]` values are unique

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

○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

○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

○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

○`<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

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

○`<object>` elements have alternate text

○Select elements have associated label elements.

○Skip links are focusable.

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

○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.

○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.

Best Practices

User Experience

Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Aspect Ratio (Displayed)	Aspect Ratio (Actual)
parallel prefix graphical result `div#tab-computing > div.row > div.col-lg-12 > img.pb-2`	www.julialang.org/assets/infra/parallel-prefix.webp	376 x 272 (1.38)	536 x 371 (1.44)

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
kit.fontawesome.com/f030d443fe.js	`Failed to load resource: the server responded with a status of 403 ()`

●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

●Serves images with appropriate resolution

●Page has the HTML doctype

●Properly defines charset

●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 clickjacking with XFO or CSP

●Mitigate DOM-based XSS with Trusted Types

●Page has valid source maps

○Redirects HTTP traffic to HTTPS

○Detected JavaScript libraries

100

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.

○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

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

○Document has a valid `rel=canonical`