Level Experience

Content is not blocked for zoom/scale

The `[user-scalable="no"]` parameter is not present in the `<meta name="viewport">` element and the `[maximum-scale]` parameter is not less than 2.Source: Lighthouse - Learn more

Content is sized correctly for the viewport

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. Source: Lighthouse - Learn more

Uses legible font sizes

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. Source: Lighthouse - Learn more

Color Contrast is satisfactory

Low-contrast text is difficult or impossible for many users to read. Background and foreground colors should have enough contrast ratio to guarantee readability. Source: Lighthouse - Learn more

Brand logo linked to homepage

Fails if doesn't have a logo or clicking it doesn't lead you to homepage.

No ending trailing paths

Fails if doesn't provide at least one of the following: main navigation options on footers, fixed or 'smart' headers/burger-icon, Back to top or close buttons.

Active section is highlighted in navigation menus

Fails if current section or page is not visually highlighted in navigation menus, except for internal section pages where it's accepted not to highlight the parent section.

Listing/overview pages with many items implements deferred loading techniques

Fails if the website doesn't provide at least one of the following: lazy-loading, load more buttons, paginator. Doesn't provide a clear reference about the total amount of items in a portfolio or blog page.

Prevent layout shiftings when loading media. Set width and height attributes on both <img> and <video> tags

Fails if transitioning from placeholders to final images changes the rendered size of the element as media loads. Not using a solid color placeholder occupying the same dimensions as the target image, or techniques such as LQIP or SQIP that hint at the content of a media item before it loads. These changes can be disorienting for users and trigger expensive DOM layout operations that consume system resources and contribute to jank.

Carousels are generally avoided (but they are acceptable if they are well implemented)

Fails if any of the following are seen: carousels auto-rotate, text is not legible, swipe is not supported, next images do not load within 1 second of swipe.

Make it easy to contact you

Fails if the website does not provide all of the following: easy to find contact options, tap to call, mailto on emails, addresses do not link to gMaps, except being embedded.

The most appropriate keyboard for the input type is provided first

Fails if most helpful keyboard not provided, i.e. input types text, tel, email, password, capitalization when appropiate, etc.

The website supports autofill for all form fields and the fields are tagged for the appropriate information from autofill

Fails if fields are not tagged for efficient browser-based autofill, making users enter data that is already known either by the website or the OS. Not filling a standard field or filling fields with the wrong content, i.e. puts house number and street name into the same field when there are separate fields for each.

All mistakes made in forms are clearly highlighted in real time, and instructions for correct completion are provided in real time

Fails if mistakes and guidance for correct completion are not highlighted in real time and/or error messages are ambiguous or unfriendly.

Avoids Application Cache

Application Cache is deprecated. Source: Lighthouse - Learn more

Avoids WebSQL DB

Web SQL is deprecated. Consider using IndexedDB instead. Source: Lighthouse - Learn more

Avoids requesting the geolocation permission on page load

Users are mistrustful of or confused by sites that request their location without context. Consider tying the request to user gestures instead. Source: Lighthouse - Learn more

robots.txt is valid

If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. Source: Lighthouse

Avoids requesting the notification permission on page load

Users are mistrustful of or confused by sites that request to send notifications without context. Consider tying the request to user gestures instead. Source: Lighthouse - Learn more

Avoids deprecated APIs

Deprecated APIs will eventually be removed from the browser. Source: Lighthouse - Learn more

Allows to paste into password input fields

The main reason why password pasting improves security is because it helps to reduce password overload. Source: Lighthouse - Learn more

Registers a Service Worker

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. Source: Lighthouse - Learn more

Responds with a 200 when offline

If you're building a Progressive Web App, consider using a service worker so that your app can work offline. Source: Lighthouse - Learn more

Uses HTTPS

All sites should be protected with HTTPS, even ones that don't handle sensitive data. 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. Source: Lighthouse - Learn more

Redirects HTTP traffic to HTTPS

If you've already set up HTTPS, make sure that you redirect all HTTP traffic to HTTPS. Source: Lighthouse - Learn more

Uses HTTP/2 for its own resources45 requests not served via HTTP/2

HTTP/2 offers many benefits over HTTP/1.1, including binary headers, multiplexing, and server push. Source: Lighthouse - Learn more

Uses passive listeners to improve scrolling performance

Mark your touch and wheel event listeners as `passive` to improve your page's scroll performance. Source: Lighthouse - Learn more

Avoid using document.write()

For users on slow connections, external scripts dynamically injected via document.write() can delay page load by tens of seconds. Source: Lighthouse - Learn more

Manifest's short_name won't be truncated when displayed on homescreen

Make your app's short_name fewer than 12 characters to ensure that it's not truncated on homescreens. Source: Lighthouse - Learn more

Configured for a custom splash screen

A default splash screen will be constructed for your app, but satisfying these requirements guarantee a high-quality splash screen that transitions the user from tapping the home screen icon to your app's first paint. Source: Lighthouse - Learn more

User can be prompted to Install the Web App

Browsers can proactively prompt users to add your app to their homescreen, which can lead to higher engagement. Source: Lighthouse - Learn more