Issue Library

High severity website issues, explained

Every landing page focuses on one critical issue: what it is, why it matters, and the fastest way to fix it with Checker.

SEO Accessibility Social previews Indexing Media
High severity accessibility

Missing Image Alt Attribute

Detects images without alt attributes on the page.

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High severity accessibility

Empty Image Alt Attribute

Finds images that has an alt attribute, but that is empty.

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High severity ux

Broken Link

Detects broken pages (4xx or 5xx status codes).

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High severity seo

Missing Title

Detects pages missing a title tag or having an empty title.

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High severity seo

Missing Canonical Tag

Detects pages missing a canonical tag.

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High severity seo

Canonical Is Relative

Detects canonical tags that use a relative URL.

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High severity indexing

Noindex Meta Tag Found

Detects pages with a noindex meta tag, preventing them from being indexed.

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High severity indexing

None Meta Tag Found

Detects pages with a none meta tag (equivalent to noindex, nofollow).

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High severity social

Missing Open Graph Title

Detects pages missing an Open Graph title tag (og:title).

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High severity social

Missing Open Graph Image

Detects pages missing an Open Graph image tag (og:image).

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High severity social

Open Graph URL Is Relative

Detects Open Graph URL tags that use a relative URL.

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High severity social

Missing Twitter Title

Detects pages missing a Twitter title meta tag (twitter:title).

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High severity social

Missing Twitter Image

Detects pages missing a Twitter image meta tag (twitter:image).

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High severity seo

Invalid JSON-LD Syntax

Detects JSON-LD script tags containing invalid JSON.

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High severity seo

Missing Schema.org Context

Detects JSON-LD structured data missing the "@context": "https://schema.org" property.

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High severity seo

Missing Schema.org Type

Detects JSON-LD structured data missing the "@type" property.

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High severity seo

Invalid Hreflang Language Code

Detects hreflang attributes with invalid language code format.

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High severity seo

Hreflang Missing Href Attribute

Detects hreflang tags missing the href attribute.

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High severity accessibility

Missing HTML lang attribute

The <html> tag is missing the lang attribute, which is important for accessibility and SEO.

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High severity accessibility

Empty HTML lang attribute

The <html> tag has a lang attribute, but it is empty.

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High severity accessibility

Missing main landmark

The page does not have a <main> element or an element with role="main".

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High severity accessibility

Input Missing Label

Detects input elements that do not have an accessible label.

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High severity accessibility

Textarea Missing Label

Detects textarea elements that do not have an accessible label.

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High severity accessibility

Select Missing Label

Detects select elements that do not have an accessible label.

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High severity accessibility

Empty Button

Detects button elements that have no text content or accessible name.

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High severity accessibility

Empty Link

Detects link (a) elements that have no text content or accessible name.

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High severity accessibility

Iframe Missing Title

Detects iframe elements that are missing a title attribute.

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High severity accessibility

Object Missing Text Alternative

Detects object elements that do not have a text alternative.

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High severity accessibility

Focusable Element in ARIA Hidden

Detects focusable elements that are hidden from screen readers using aria-hidden="true".

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High severity accessibility

Focusable Element with Presentation Role

Detects elements with role="presentation" or role="none" that are focusable.

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High severity accessibility

Image Role Missing Label

Detects elements with role="img" that do not have an accessible label.

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High severity accessibility

Dialog Role Missing Label

Detects elements with role="dialog" or "alertdialog" that do not have an accessible label.

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High severity accessibility

Cell Role Missing Parent Row

Detects elements with role="cell" or "gridcell" that are not contained within a role="row".

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High severity accessibility

Row Role Missing Parent Grid/Table

Detects elements with role="row" that are not contained within a role="grid", "treegrid", or "table".

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High severity media

Video Missing Track

Detects video elements that are missing a track element (captions/subtitles).

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High severity media

Audio Missing Track

Detects audio elements that are missing a track element (transcript/captions).

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High severity media

Video Autoplay Missing Controls

Detects video elements with autoplay enabled but missing the controls attribute.

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High severity accessibility

Input Image Missing Alt Attribute

Detects input elements with type='image' that are missing an alt attribute or have an empty alt attribute.

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