There were issues affecting this run of Lighthouse:
- Something went wrong with recording the trace over your page load. Please run Lighthouse again. (NO_FCP)
Values are estimated and may vary. The performance score is calculated directly from these metrics.See calculator.
Metrics
First Contentful Paint
Error!
Required traces gatherer did not run.
Largest Contentful Paint
Error!
Required traces gatherer did not run.
Total Blocking Time
Error!
Required traces gatherer did not run.
Cumulative Layout Shift
Error!
Required traces gatherer did not run.
Speed Index
Error!
Required traces gatherer did not run.
Show audits relevant to:
Diagnostics
Eliminate render-blocking resources Error!Required TagsBlockingFirstPaint gatherer did not run.
Required TagsBlockingFirstPaint gatherer did not run.
Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles. Learn how to eliminate render-blocking resources.FCPLCP
Properly size images Error!Required ImageElements gatherer did not run.
Required ImageElements gatherer did not run.
Serve images that are appropriately-sized to save cellular data and improve load time. Learn how to size images.
Minify CSS Error!Required CSSUsage gatherer did not run.
Required CSSUsage gatherer did not run.
Minify JavaScript Error!Required Scripts gatherer did not run.
Required Scripts gatherer did not run.
Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.FCPLCP
Reduce unused CSS Error!Required CSSUsage gatherer did not run.
Required CSSUsage gatherer did not run.
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.FCPLCP
Reduce unused JavaScript Error!Required JsUsage gatherer did not run.
Required JsUsage gatherer did not run.
Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.LCP
Efficiently encode images Error!Required OptimizedImages gatherer did not run.
Required OptimizedImages gatherer did not run.
Optimized images load faster and consume less cellular data. Learn how to efficiently encode images.
Serve images in next-gen formats Error!Required OptimizedImages gatherer did not run.
Required OptimizedImages gatherer did not run.
Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. Learn more about modern image formats.
Enable text compression Error!Required ResponseCompression gatherer did not run.
Required ResponseCompression gatherer did not run.
Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes. Learn more about text compression.FCPLCP
Preconnect to required origins Error!Required traces gatherer did not run.
Required traces gatherer did not run.
Consider adding
preconnect
or dns-prefetch
resource hints to establish early connections to important third-party origins. Learn how to preconnect to required origins.FCPLCP Initial server response time was short Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Keep the server response time for the main document short because all other requests depend on it. Learn more about the Time to First Byte metric.FCPLCP
Avoid multiple page redirects Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.FCPLCP
Preload key requests Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Consider using
<link rel=preload>
to prioritize fetching resources that are currently requested later in page load. Learn how to preload key requests.FCPLCP Use HTTP/2 Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
HTTP/2 offers many benefits over HTTP/1.1, including binary headers and multiplexing. Learn more about HTTP/2.
Use video formats for animated content Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Large GIFs are inefficient for delivering animated content. Consider using MPEG4/WebM videos for animations and PNG/WebP for static images instead of GIF to save network bytes. Learn more about efficient video formatsLCP
Remove duplicate modules in JavaScript bundles Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity. TBT
Avoid serving legacy JavaScript to modern browsers Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Polyfills and transforms enable legacy browsers to use new JavaScript features. However, many aren't necessary for modern browsers. For your bundled JavaScript, adopt a modern script deployment strategy using module/nomodule feature detection to reduce the amount of code shipped to modern browsers, while retaining support for legacy browsers. Learn how to use modern JavaScriptTBT
Preload Largest Contentful Paint image Error!Required traces gatherer did not run.
Required traces gatherer did not run.
If the LCP element is dynamically added to the page, you should preload the image in order to improve LCP. Learn more about preloading LCP elements.LCP
Avoids enormous network payloads Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.LCP
Uses efficient cache policy on static assets Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
A long cache lifetime can speed up repeat visits to your page. Learn more about efficient cache policies.
Avoids an excessive DOM size Error!Required DOMStats gatherer did not run.
Required DOMStats gatherer did not run.
A large DOM will increase memory usage, cause longer style calculations, and produce costly layout reflows. Learn how to avoid an excessive DOM size.TBT
Avoid chaining critical requests Error!Required traces gatherer did not run.
Required traces gatherer did not run.
The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load. Learn how to avoid chaining critical requests.FCPLCP
User Timing marks and measures Error!Required traces gatherer did not run.
Required traces gatherer did not run.
Consider instrumenting your app with the User Timing API to measure your app's real-world performance during key user experiences. Learn more about User Timing marks.
JavaScript execution time Error!Required traces gatherer did not run.
Required traces gatherer did not run.
Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.TBT
Minimizes main-thread work Error!Required traces gatherer did not run.
Required traces gatherer did not run.
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 workTBT
All text remains visible during webfont loads Error!Required devtoolsLogs gatherer did not run. Warnings: - Lighthouse was unable to automatically check the font-display value for the following URL: https://secure-ds.serving-sys.com/resources/PROD/html5/105657/20190307/1074580285/43862346571980472/fonts/IBMPlexSans-Light-Latin1.woff.
- Lighthouse was unable to automatically check the font-display value for the following URL: https://secure-ds.serving-sys.com/resources/PROD/html5/105657/20190307/1074580285/43862346571980472/fonts/IBMPlexSans-Bold-Latin1.woff.
Required devtoolsLogs gatherer did not run.
- Lighthouse was unable to automatically check the font-display value for the following URL: https://secure-ds.serving-sys.com/resources/PROD/html5/105657/20190307/1074580285/43862346571980472/fonts/IBMPlexSans-Light-Latin1.woff.
- Lighthouse was unable to automatically check the font-display value for the following URL: https://secure-ds.serving-sys.com/resources/PROD/html5/105657/20190307/1074580285/43862346571980472/fonts/IBMPlexSans-Bold-Latin1.woff.
Leverage the
font-display
CSS feature to ensure text is user-visible while webfonts are loading. Learn more about font-display
.FCPLCP Keep request counts low and transfer sizes small Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
To set budgets for the quantity and size of page resources, add a budget.json file. Learn more about performance budgets.
Minimize third-party usage Error!Required traces gatherer did not run.
Required traces gatherer did not run.
Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading. Learn how to minimize third-party impact.TBT
Lazy load third-party resources with facades Error!Required traces gatherer did not run.
Required traces gatherer did not run.
Some third-party embeds can be lazy loaded. Consider replacing them with a facade until they are required. Learn how to defer third-parties with a facade.TBT
Largest Contentful Paint element Error!Required traces gatherer did not run.
Required traces gatherer did not run.
This is the largest contentful element painted within the viewport. Learn more about the Largest Contentful Paint elementLCP
Largest Contentful Paint image was not lazily loaded Error!Required TraceElements gatherer did not run.
Required TraceElements gatherer did not run.
Above-the-fold images that are lazily loaded render later in the page lifecycle, which can delay the largest contentful paint. Learn more about optimal lazy loading.LCP
Avoid large layout shifts Error!Required traces gatherer did not run.
Required traces gatherer did not run.
These DOM elements contribute most to the CLS of the page. Learn how to improve CLSCLS
Uses passive listeners to improve scrolling performance Error!Required ConsoleMessages gatherer did not run.
Required ConsoleMessages gatherer did not run.
Consider marking your touch and wheel event listeners as
passive
to improve your page's scroll performance. Learn more about adopting passive event listeners. Avoids document.write()
Error!Required ConsoleMessages gatherer did not run.
document.write()
Error!Required ConsoleMessages gatherer did not run.
For users on slow connections, external scripts dynamically injected via
document.write()
can delay page load by tens of seconds. Learn how to avoid document.write(). Avoid long main-thread tasks Error!Required traces gatherer did not run.
Required traces gatherer did not run.
Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay. Learn how to avoid long main-thread tasksTBT
Avoid non-composited animations Error!Required TraceElements gatherer did not run.
Required TraceElements gatherer did not run.
Animations which are not composited can be janky and increase CLS. Learn how to avoid non-composited animationsCLS
Image elements have explicit width
and height
Error!Required ImageElements gatherer did not run.
width
and height
Error!Required ImageElements gatherer did not run.
Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensionsCLS
Has a <meta name="viewport">
tag with width
or initial-scale
Error!Required MetaElements gatherer did not run.
<meta name="viewport">
tag with width
or initial-scale
Error!Required MetaElements gatherer did not run.
A
<meta name="viewport">
not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.TBT Page didn't prevent back/forward cache restoration Error!Required BFCacheFailures gatherer did not run.
Required BFCacheFailures gatherer did not run.
Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache
Passed audits (1) Show Hide
Passed audits (1)
Show Hide
Defer offscreen images Warnings: Invalid image sizing information: https://cdn.cnn.com/cnn/.e1mo/img/4.0/vr/vr_new_asset.png
Consider lazy-loading offscreen and hidden images after all critical resources have finished loading to lower time to interactive. Learn how to defer offscreen images.
These checks highlight opportunities to improve the accessibility of your web app. Only a subset of accessibility issues can be automatically detected so manual testing is also encouraged.
ARIA
[aria-*]
attributes match their roles Error!Required Accessibility gatherer did not run.
[aria-*]
attributes match their roles Error!Required Accessibility gatherer did not run.
Each ARIA
role
supports a specific subset of aria-*
attributes. Mismatching these invalidates the aria-*
attributes. Learn how to match ARIA attributes to their roles. [aria-hidden="true"]
is not present on the document <body>
Error!Required Accessibility gatherer did not run.
[aria-hidden="true"]
is not present on the document <body>
Error!Required Accessibility gatherer did not run.
Assistive technologies, like screen readers, work inconsistently when
aria-hidden="true"
is set on the document <body>
. Learn how aria-hidden
affects the document body. [role]
s have all required [aria-*]
attributes Error!Required Accessibility gatherer did not run.
[role]
s have all required [aria-*]
attributes Error!Required Accessibility gatherer did not run.
Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more about roles and required attributes.
Elements with an ARIA [role]
that require children to contain a specific [role]
have all required children. Error!Required Accessibility gatherer did not run.
[role]
that require children to contain a specific [role]
have all required children. Error!Required Accessibility gatherer did not run.
Some ARIA parent roles must contain specific child roles to perform their intended accessibility functions. Learn more about roles and required children elements.
[role]
s are contained by their required parent element Error!Required Accessibility gatherer did not run.
[role]
s are contained by their required parent element Error!Required Accessibility gatherer did not run.
Some ARIA child roles must be contained by specific parent roles to properly perform their intended accessibility functions. Learn more about ARIA roles and required parent element.
[role]
values are valid Error!Required Accessibility gatherer did not run.
[role]
values are valid Error!Required Accessibility gatherer did not run.
ARIA roles must have valid values in order to perform their intended accessibility functions. Learn more about valid ARIA roles.
[aria-*]
attributes have valid values Error!Required Accessibility gatherer did not run.
[aria-*]
attributes have valid values Error!Required Accessibility gatherer did not run.
Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid values. Learn more about valid values for ARIA attributes.
[aria-*]
attributes are valid and not misspelled Error!Required Accessibility gatherer did not run.
[aria-*]
attributes are valid and not misspelled Error!Required Accessibility gatherer did not run.
Assistive technologies, like screen readers, can't interpret ARIA attributes with invalid names. Learn more about valid ARIA attributes.
ARIA IDs are unique Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
The value of an ARIA ID must be unique to prevent other instances from being overlooked by assistive technologies. Learn how to fix duplicate ARIA IDs.
button
, link
, and menuitem
elements have accessible names Error!Required Accessibility gatherer did not run.
button
, link
, and menuitem
elements have accessible names Error!Required Accessibility gatherer did not run.
When an element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to make command elements more accessible.
[aria-hidden="true"]
elements do not contain focusable descendents Error!Required Accessibility gatherer did not run.
[aria-hidden="true"]
elements do not contain focusable descendents Error!Required Accessibility gatherer did not run.
Focusable descendents within an
[aria-hidden="true"]
element prevent those interactive elements from being available to users of assistive technologies like screen readers. Learn how aria-hidden
affects focusable elements. ARIA input fields have accessible names Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
When an input field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about input field labels.
ARIA meter
elements have accessible names Error!Required Accessibility gatherer did not run.
meter
elements have accessible names Error!Required Accessibility gatherer did not run.
When a meter element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to name
meter
elements. ARIA progressbar
elements have accessible names Error!Required Accessibility gatherer did not run.
progressbar
elements have accessible names Error!Required Accessibility gatherer did not run.
When a
progressbar
element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to label progressbar
elements. ARIA toggle fields have accessible names Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
When a toggle field doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about toggle fields.
ARIA tooltip
elements have accessible names Error!Required Accessibility gatherer did not run.
tooltip
elements have accessible names Error!Required Accessibility gatherer did not run.
When a tooltip element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn how to name
tooltip
elements. ARIA treeitem
elements have accessible names Error!Required Accessibility gatherer did not run.
treeitem
elements have accessible names Error!Required Accessibility gatherer did not run.
When a
treeitem
element doesn't have an accessible name, screen readers announce it with a generic name, making it unusable for users who rely on screen readers. Learn more about labeling treeitem
elements.Names and labels
Buttons have an accessible name Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
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.
Image elements have [alt]
attributes Error!Required Accessibility gatherer did not run.
[alt]
attributes Error!Required Accessibility gatherer did not run.
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. <input type="image">
elements have [alt]
text Error!Required Accessibility gatherer did not run.
<input type="image">
elements have [alt]
text Error!Required Accessibility gatherer did not run.
When an image is being used as an
<input>
button, providing alternative text can help screen reader users understand the purpose of the button. Learn about input image alt text. Form elements have associated labels Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
Labels ensure that form controls are announced properly by assistive technologies, like screen readers. Learn more about form element labels.
Document has a <title>
element Error!Required Accessibility gatherer did not run.
<title>
element Error!Required Accessibility gatherer did not run.
The title gives screen reader users an overview of the page, and search engine users rely on it heavily to determine if a page is relevant to their search. Learn more about document titles.
<frame>
or <iframe>
elements have a title Error!Required Accessibility gatherer did not run.
<frame>
or <iframe>
elements have a title Error!Required Accessibility gatherer did not run.
Screen reader users rely on frame titles to describe the contents of frames. Learn more about frame titles.
Links have a discernible name Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
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.
<object>
elements have alternate text Error!Required Accessibility gatherer did not run.
<object>
elements have alternate text Error!Required Accessibility gatherer did not run.
Screen readers cannot translate non-text content. Adding alternate text to
<object>
elements helps screen readers convey meaning to users. Learn more about alt text for object
elements. No form fields have multiple labels Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
Form fields with multiple labels can be confusingly announced by assistive technologies like screen readers which use either the first, the last, or all of the labels. Learn how to use form labels.
Best practices
The document does not use <meta http-equiv="refresh">
Error!Required Accessibility gatherer did not run.
<meta http-equiv="refresh">
Error!Required Accessibility gatherer did not run.
Users do not expect a page to refresh automatically, and doing so will move focus back to the top of the page. This may create a frustrating or confusing experience. Learn more about the refresh meta tag.
[user-scalable="no"]
is not used in the <meta name="viewport">
element and the [maximum-scale]
attribute is not less than 5. Error!Required Accessibility gatherer did not run.
[user-scalable="no"]
is not used in the <meta name="viewport">
element and the [maximum-scale]
attribute is not less than 5. Error!Required Accessibility gatherer did not run.
Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.
Audio and video
These are opportunities to provide alternative content for audio and video. This may improve the experience for users with hearing or vision impairments.Navigation
[accesskey]
values are unique Error!Required Accessibility gatherer did not run.
[accesskey]
values are unique Error!Required Accessibility gatherer did not run.
Access keys let users quickly focus a part of the page. For proper navigation, each access key must be unique. Learn more about access keys.
The page contains a heading, skip link, or landmark region Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
Adding ways to bypass repetitive content lets keyboard users navigate the page more efficiently. Learn more about bypass blocks.
[id]
attributes on active, focusable elements are unique Error!Required Accessibility gatherer did not run.
[id]
attributes on active, focusable elements are unique Error!Required Accessibility gatherer did not run.
All focusable elements must have a unique
id
to ensure that they're visible to assistive technologies. Learn how to fix duplicate id
s. No element has a [tabindex]
value greater than 0 Error!Required Accessibility gatherer did not run.
[tabindex]
value greater than 0 Error!Required Accessibility gatherer did not run.
A value greater than 0 implies an explicit navigation ordering. Although technically valid, this often creates frustrating experiences for users who rely on assistive technologies. Learn more about the
tabindex
attribute. Heading elements appear in a sequentially-descending order Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
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.
Contrast
Background and foreground colors have a sufficient contrast ratio Error!Required Accessibility gatherer did not run.
Required Accessibility gatherer did not run.
Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.
Tables and lists
<dl>
's contain only properly-ordered <dt>
and <dd>
groups, <script>
, <template>
or <div>
elements. Error!Required Accessibility gatherer did not run.
<dl>
's contain only properly-ordered <dt>
and <dd>
groups, <script>
, <template>
or <div>
elements. Error!Required Accessibility gatherer did not run.
When definition lists are not properly marked up, screen readers may produce confusing or inaccurate output. Learn how to structure definition lists correctly.
Definition list items are wrapped in <dl>
elements Error!Required Accessibility gatherer did not run.
<dl>
elements Error!Required Accessibility gatherer did not run.
Definition list items (
<dt>
and <dd>
) must be wrapped in a parent <dl>
element to ensure that screen readers can properly announce them. Learn how to structure definition lists correctly. Lists contain only <li>
elements and script supporting elements (<script>
and <template>
). Error!Required Accessibility gatherer did not run.
<li>
elements and script supporting elements (<script>
and <template>
). Error!Required Accessibility gatherer did not run.
Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. Learn more about proper list structure.
List items (<li>
) are contained within <ul>
, <ol>
or <menu>
parent elements Error!Required Accessibility gatherer did not run.
<li>
) are contained within <ul>
, <ol>
or <menu>
parent elements Error!Required Accessibility gatherer did not run.
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. Cells in a <table>
element that use the [headers]
attribute refer to table cells within the same table. Error!Required Accessibility gatherer did not run.
<table>
element that use the [headers]
attribute refer to table cells within the same table. Error!Required Accessibility gatherer did not run.
Screen readers have features to make navigating tables easier. Ensuring
<td>
cells using the [headers]
attribute only refer to other cells in the same table may improve the experience for screen reader users. Learn more about the headers
attribute. <th>
elements and elements with [role="columnheader"/"rowheader"]
have data cells they describe. Error!Required Accessibility gatherer did not run.
<th>
elements and elements with [role="columnheader"/"rowheader"]
have data cells they describe. Error!Required Accessibility gatherer did not run.
Screen readers have features to make navigating tables easier. Ensuring table headers always refer to some set of cells may improve the experience for screen reader users. Learn more about table headers.
Internationalization and localization
<html>
element has a [lang]
attribute Error!Required Accessibility gatherer did not run.
<html>
element has a [lang]
attribute Error!Required Accessibility gatherer did not run.
If a page doesn't specify a
lang
attribute, a screen reader assumes that the page is in the default language that the user chose when setting up the screen reader. If the page isn't actually in the default language, then the screen reader might not announce the page's text correctly. Learn more about the lang
attribute. <html>
element has a valid value for its [lang]
attribute Error!Required Accessibility gatherer did not run.
<html>
element has a valid value for its [lang]
attribute Error!Required Accessibility gatherer did not run.
Specifying a valid BCP 47 language helps screen readers announce text properly. Learn how to use the
lang
attribute. [lang]
attributes have a valid value Error!Required Accessibility gatherer did not run.
[lang]
attributes have a valid value Error!Required Accessibility gatherer did not run.
Specifying a valid BCP 47 language on elements helps ensure that text is pronounced correctly by a screen reader. Learn how to use the
lang
attribute. Additional items to manually check (10) Show Hide
Additional items to manually check (10)
Show Hide
The page has a logical tab order
Tabbing through the page follows the visual layout. Users cannot focus elements that are offscreen. Learn more about logical tab ordering.
Interactive controls are keyboard focusable
Custom interactive controls are keyboard focusable and display a focus indicator. Learn how to make custom controls focusable.
Interactive elements indicate their purpose and state
Interactive elements, such as links and buttons, should indicate their state and be distinguishable from non-interactive elements. Learn how to decorate interactive elements with affordance hints.
The user's focus is directed to new content added to the page
If new content, such as a dialog, is added to the page, the user's focus is directed to it. Learn how to direct focus to new content.
User focus is not accidentally trapped in a region
A user can tab into and out of any control or region without accidentally trapping their focus. Learn how to avoid focus traps.
Custom controls have associated labels
Custom interactive controls have associated labels, provided by aria-label or aria-labelledby. Learn more about custom controls and labels.
Custom controls have ARIA roles
Custom interactive controls have appropriate ARIA roles. Learn how to add roles to custom controls.
Visual order on the page follows DOM order
DOM order matches the visual order, improving navigation for assistive technology. Learn more about DOM and visual ordering.
Offscreen content is hidden from assistive technology
Offscreen content is hidden with display: none or aria-hidden=true. Learn how to properly hide offscreen content.
HTML5 landmark elements are used to improve navigation
Landmark elements (
<main>
, <nav>
, etc.) are used to improve the keyboard navigation of the page for assistive technology. Learn more about landmark elements.Trust and Safety
Uses HTTPS Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being served over HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more about HTTPS.
Avoids requesting the geolocation permission on page load Error!Required ConsoleMessages gatherer did not run.
Required ConsoleMessages gatherer did not run.
Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to a user action instead. Learn more about the geolocation permission.
Avoids requesting the notification permission on page load Error!Required ConsoleMessages gatherer did not run.
Required ConsoleMessages gatherer did not run.
Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. Learn more about responsibly getting permission for notifications.
Ensure CSP is effective against XSS attacks Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
A strong Content Security Policy (CSP) significantly reduces the risk of cross-site scripting (XSS) attacks. Learn how to use a CSP to prevent XSS
User Experience
Allows users to paste into input fields Error!Required Inputs gatherer did not run.
Required Inputs gatherer did not run.
Preventing input pasting is a bad practice for the UX, and weakens security by blocking password managers.Learn more about user-friendly input fields.
Displays images with correct aspect ratio Error!Required ImageElements gatherer did not run.
Required ImageElements gatherer did not run.
Image display dimensions should match natural aspect ratio. Learn more about image aspect ratio.
Serves images with appropriate resolution Error!Required ImageElements gatherer did not run.
Required ImageElements gatherer did not run.
Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn how to provide responsive images.
Fonts with font-display: optional
are preloaded Error!Required devtoolsLogs gatherer did not run.
font-display: optional
are preloaded Error!Required devtoolsLogs gatherer did not run.
Preload
optional
fonts so first-time visitors may use them. Learn more about preloading fontsBrowser Compatibility
Page has the HTML doctype Error!Required Doctype gatherer did not run.
Required Doctype gatherer did not run.
Specifying a doctype prevents the browser from switching to quirks-mode. Learn more about the doctype declaration.
Properly defines charset Error!Required MainDocumentContent gatherer did not run.
Required MainDocumentContent gatherer did not run.
A character encoding declaration is required. It can be done with a
<meta>
tag in the first 1024 bytes of the HTML or in the Content-Type HTTP response header. Learn more about declaring the character encoding.General
Avoids unload
event listeners Error!Required GlobalListeners gatherer did not run.
unload
event listeners Error!Required GlobalListeners gatherer did not run.
The
unload
event does not fire reliably and listening for it can prevent browser optimizations like the Back-Forward Cache. Use pagehide
or visibilitychange
events instead. Learn more about unload event listeners Avoids deprecated APIs Error!Required InspectorIssues gatherer did not run.
Required InspectorIssues gatherer did not run.
Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.
No browser errors logged to the console Error!Required ConsoleMessages gatherer did not run.
Required ConsoleMessages gatherer did not run.
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
No issues in the Issues
panel in Chrome Devtools Error!Required InspectorIssues gatherer did not run.
Issues
panel in Chrome Devtools Error!Required InspectorIssues gatherer did not run.
Issues logged to the
Issues
panel in Chrome Devtools indicate unresolved problems. They can come from network request failures, insufficient security controls, and other browser concerns. Open up the Issues panel in Chrome DevTools for more details on each issue. Detected JavaScript libraries Error!Required Stacks gatherer did not run.
Required Stacks gatherer did not run.
All front-end JavaScript libraries detected on the page. Learn more about this JavaScript library detection diagnostic audit.
Page has valid source maps Error!Required Scripts gatherer did not run.
Required Scripts gatherer did not run.
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.
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.
Mobile Friendly
Has a <meta name="viewport">
tag with width
or initial-scale
Error!Required MetaElements gatherer did not run.
<meta name="viewport">
tag with width
or initial-scale
Error!Required MetaElements gatherer did not run.
A
<meta name="viewport">
not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.TBT Document uses legible font sizes Error!Required FontSize gatherer did not run.
Required FontSize gatherer did not run.
Font sizes less than 12px are too small to be legible and require mobile visitors to “pinch to zoom” in order to read. Strive to have >60% of page text ≥12px. Learn more about legible font sizes.
Tap targets are sized appropriately Error!Required MetaElements gatherer did not run.
Required MetaElements gatherer did not run.
Interactive elements like buttons and links should be large enough (48x48px), or have enough space around them, to be easy enough to tap without overlapping onto other elements. Learn more about tap targets.
Content Best Practices
Document has a <title>
element Error!Required Accessibility gatherer did not run.
<title>
element Error!Required Accessibility gatherer did not run.
The title gives screen reader users an overview of the page, and search engine users rely on it heavily to determine if a page is relevant to their search. Learn more about document titles.
Document has a meta description Error!Required MetaElements gatherer did not run.
Required MetaElements gatherer did not run.
Meta descriptions may be included in search results to concisely summarize page content. Learn more about the meta description.
Links have descriptive text Error!Required AnchorElements gatherer did not run.
Required AnchorElements gatherer did not run.
Descriptive link text helps search engines understand your content. Learn how to make links more accessible.
Image elements have [alt]
attributes Error!Required Accessibility gatherer did not run.
[alt]
attributes Error!Required Accessibility gatherer did not run.
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. Document has a valid hreflang
Error!Required LinkElements gatherer did not run.
hreflang
Error!Required LinkElements gatherer did not run.
hreflang links tell search engines what version of a page they should list in search results for a given language or region. Learn more about
hreflang
. Document has a valid rel=canonical
Error!Required LinkElements gatherer did not run.
rel=canonical
Error!Required LinkElements gatherer did not run.
Canonical links suggest which URL to show in search results. Learn more about canonical links.
Document avoids plugins Error!Required EmbeddedContent gatherer did not run.
Required EmbeddedContent gatherer did not run.
Search engines can't index plugin content, and many devices restrict plugins or don't support them. Learn more about avoiding plugins.
Crawling and Indexing
Page has successful HTTP status code Error!Required devtoolsLogs gatherer did not run.
Required devtoolsLogs gatherer did not run.
Pages with unsuccessful HTTP status codes may not be indexed properly. Learn more about HTTP status codes.
Links are crawlable Error!Required AnchorElements gatherer did not run.
Required AnchorElements gatherer did not run.
Search engines may use
href
attributes on links to crawl websites. Ensure that the href
attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn how to make links crawlable Page isn’t blocked from indexing Error!Required MetaElements gatherer did not run.
Required MetaElements gatherer did not run.
Search engines are unable to include your pages in search results if they don't have permission to crawl them. Learn more about crawler directives.
robots.txt is valid Error!Required RobotsTxt gatherer did not run.
Required RobotsTxt gatherer did not run.
If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. Learn more about robots.txt.
Additional items to manually check (1) Show Hide
Additional items to manually check (1)
Show Hide
Structured data is valid
Run the Structured Data Testing Tool and the Structured Data Linter to validate structured data. Learn more about Structured Data.
These checks validate the aspects of a Progressive Web App. Learn what makes a good Progressive Web App.
Installable
Web app manifest and service worker meet the installability requirements Error!Required WebAppManifest gatherer did not run.
Required WebAppManifest gatherer did not run.
Service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. With proper service worker and manifest implementations, browsers can proactively prompt users to add your app to their homescreen, which can lead to higher engagement. Learn more about manifest installability requirements.
PWA Optimized
Registers a service worker that controls page and start_url
Error!Required ServiceWorker gatherer did not run.
start_url
Error!Required ServiceWorker gatherer did not run.
The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. Learn more about Service Workers.
Configured for a custom splash screen Error!Required WebAppManifest gatherer did not run.
Required WebAppManifest gatherer did not run.
A themed splash screen ensures a high-quality experience when users launch your app from their homescreens. Learn more about splash screens.
Sets a theme color for the address bar. Error!Required WebAppManifest gatherer did not run.
Required WebAppManifest gatherer did not run.
The browser address bar can be themed to match your site. Learn more about theming the address bar.
Content is sized correctly for the viewport Error!Required ViewportDimensions gatherer did not run.
Required ViewportDimensions gatherer did not run.
If the width of your app's content doesn't match the width of the viewport, your app might not be optimized for mobile screens. Learn how to size content for the viewport.
Has a <meta name="viewport">
tag with width
or initial-scale
Error!Required MetaElements gatherer did not run.
<meta name="viewport">
tag with width
or initial-scale
Error!Required MetaElements gatherer did not run.
A
<meta name="viewport">
not only optimizes your app for mobile screen sizes, but also prevents a 300 millisecond delay to user input. Learn more about using the viewport meta tag.TBT Manifest has a maskable icon Error!Required WebAppManifest gatherer did not run.
Required WebAppManifest gatherer did not run.
A maskable icon ensures that the image fills the entire shape without being letterboxed when installing the app on a device. Learn about maskable manifest icons.
Additional items to manually check (3) Show Hide
Additional items to manually check (3)
Show Hide
Site works cross-browser
To reach the most number of users, sites should work across every major browser. Learn about cross-browser compatibility.
Page transitions don't feel like they block on the network
Transitions should feel snappy as you tap around, even on a slow network. This experience is key to a user's perception of performance. Learn more about page transitions.
Each page has a URL
Ensure individual pages are deep linkable via URL and that URLs are unique for the purpose of shareability on social media. Learn more about providing deep links.