Rules

Every rule cora knows, under the engine that runs it. Each rule’s ID links to CORA’s guidance on fixing what it finds, which links the rule’s own documentation, and the tables give each rule’s:

• Level, the WCAG version and level that first require what it checks, or best practice for a rule no WCAG success criterion requires.
• WCAG success criteria, the ones it checks, if any.
• Category, what it checks, which Categories describes.
• Severity, the severity of the issues it finds.
• Fix class, what fixing the issues it finds takes, which Fix classes describes.
• Description of what it checks.

Each rule of an engine that checks pages, such as axe, is in the default set, which Vispero keeps, or outside it, such as a rule axe-core calls experimental or deprecated. The config’s rules decides which run: its standard, WCAG 2.2 AA by default, runs the rules of the default set at its version and level and below, bestPractices runs the default set’s best practices, and overrides set the rules a rule ID, a WCAG success criterion, a category or an engine names to on, off or report, which shows their findings without ever failing the gate. A WCAG success criterion, a category or an engine reaches only the rules of the default set, so a rule outside it runs only where an override names it by its ID, as axe/p-as-heading here:

cora.config.ts

import { defineConfig } from '@vispero/cora/config';

export default defineConfig({
  rules: {
    standard: 'WCAG 2.1 AA',
    overrides: {
      'axe/region': 'off',
      '1.4.6': 'on',
      forms: 'report',
      'axe/p-as-heading': 'on',
    },
  },
});

Categories

Category	Its rules check that
aria	ARIA roles, states and properties are valid, and used where the specification allows them.
color	Text has enough contrast with its background, and color is not the only way information is shown.
forms	Form fields have labels, and say what information they collect.
keyboard	The page works from a keyboard: focus reaches what it should, and people can skip past repeated content.
language	The page, and each part in another language, name their language.
name-role-value	Interactive elements have an accessible name, and expose their role and state.
parsing	The markup is unambiguous and current: no two elements share an ID, and no obsolete element such as marquee is used.
semantics	Headings and landmarks are marked up for what they are, and links and labels say what they do.
sensory-and-visual-cues	People can zoom and resize the page, and targets are large enough to hit.
structure	Lists and other structure are marked up as the content is organized, and the layout adapts to text spacing and orientation.
tables	Data tables mark their headers, and associate each cell with them.
text-alternatives	Images and other non-text content have a text alternative, and documents and frames a title.
time-and-media	Audio and video have captions, and content that moves, blinks or refreshes can be controlled.

Fix classes

Fix class	Meaning
mechanical	A fix needs no authored text or visual decision.
content	A fix needs authored text.
design	A fix needs a visual decision.
manual	A fix needs a person to work out what to change, beyond authored text or a visual decision.

axe

In the default set

These rules run where the config’s standard covers their level, or, for a best practice, where bestPractices is on, unless an override says otherwise. By default says whether each runs with the defaults, WCAG 2.2 AA and the best practices.

Rule	By default	Level	WCAG	Category	Severity	Fix class	Description
axe/accesskeys	on	best practice	none	keyboard	serious	mechanical	accesskey attribute value should be unique
axe/area-alt	on	2.0 A	2.4.4, 4.1.2	text-alternatives	critical	content	Active <area> elements must have alternative text
axe/aria-allowed-attr	on	2.0 A	4.1.2	aria	critical	mechanical	Elements must only use supported ARIA attributes
axe/aria-allowed-role	on	best practice	none	aria	minor	mechanical	ARIA role should be appropriate for the element
axe/aria-braille-equivalent	on	2.0 A	4.1.2	aria	serious	content	aria-braille attributes must have a non-braille equivalent
axe/aria-command-name	on	2.0 A	4.1.2	aria	serious	content	ARIA commands must have an accessible name
axe/aria-conditional-attr	on	2.0 A	4.1.2	aria	serious	mechanical	ARIA attributes must be used as specified for the element’s role
axe/aria-deprecated-role	on	2.0 A	4.1.2	aria	minor	mechanical	Deprecated ARIA roles must not be used
axe/aria-dialog-name	on	best practice	none	aria	serious	content	ARIA dialog and alertdialog nodes should have an accessible name
axe/aria-hidden-body	on	2.0 A	1.3.1, 4.1.2	aria	critical	mechanical	aria-hidden=“true” must not be present on the document body
axe/aria-hidden-focus	on	2.0 A	4.1.2	name-role-value	serious	mechanical	ARIA hidden element must not be focusable or contain focusable elements
axe/aria-input-field-name	on	2.0 A	4.1.2	aria	serious	content	ARIA input fields must have an accessible name
axe/aria-meter-name	on	2.0 A	1.1.1	aria	serious	content	ARIA meter nodes must have an accessible name
axe/aria-progressbar-name	on	2.0 A	1.1.1	aria	serious	content	ARIA progressbar nodes must have an accessible name
axe/aria-prohibited-attr	on	2.0 A	4.1.2	aria	serious	mechanical	Elements must only use permitted ARIA attributes
axe/aria-required-attr	on	2.0 A	4.1.2	aria	critical	mechanical	Required ARIA attributes must be provided
axe/aria-required-children	on	2.0 A	1.3.1	aria	critical	mechanical	Certain ARIA roles must contain particular children
axe/aria-required-parent	on	2.0 A	1.3.1	aria	critical	mechanical	Certain ARIA roles must be contained by particular parents
axe/aria-roles	on	2.0 A	4.1.2	aria	critical	mechanical	ARIA roles used must conform to valid values
axe/aria-tab-name	on	2.0 A	4.1.2	aria	serious	content	ARIA tab nodes must have an accessible name
axe/aria-text	on	best practice	none	aria	serious	mechanical	“role=text” should have no focusable descendants
axe/aria-toggle-field-name	on	2.0 A	4.1.2	aria	serious	content	ARIA toggle fields must have an accessible name
axe/aria-tooltip-name	on	2.0 A	4.1.2	aria	serious	content	ARIA tooltip nodes must have an accessible name
axe/aria-treeitem-name	on	best practice	none	aria	serious	content	ARIA treeitem nodes should have an accessible name
axe/aria-valid-attr	on	2.0 A	4.1.2	aria	critical	mechanical	ARIA attributes must conform to valid names
axe/aria-valid-attr-value	on	2.0 A	4.1.2	aria	critical	mechanical	ARIA attributes must conform to valid values
axe/autocomplete-valid	on	2.1 AA	1.3.5	forms	serious	mechanical	autocomplete attribute must be used correctly
axe/avoid-inline-spacing	on	2.1 AA	1.4.12	structure	serious	mechanical	Inline text spacing must be adjustable with custom stylesheets
axe/blink	on	2.0 A	2.2.2	time-and-media	serious	mechanical	<blink> elements are deprecated and must not be used
axe/button-name	on	2.0 A	4.1.2	name-role-value	critical	content	Buttons must have discernible text
axe/bypass	on	2.0 A	2.4.1	keyboard	serious	manual	Page must have means to bypass repeated blocks
axe/color-contrast	on	2.0 AA	1.4.3	color	serious	design	Elements must meet minimum color contrast ratio thresholds
axe/color-contrast-enhanced	off	2.0 AAA	1.4.6	color	serious	design	Elements must meet enhanced color contrast ratio thresholds
axe/definition-list	on	2.0 A	1.3.1	structure	serious	mechanical	<dl> elements must only directly contain properly-ordered <dt> and <dd> groups, <script>, <template> or <div> elements
axe/dlitem	on	2.0 A	1.3.1	structure	serious	mechanical	<dt> and <dd> elements must be contained by a <dl>
axe/document-title	on	2.0 A	2.4.2	text-alternatives	serious	content	Documents must have <title> element to aid in navigation
axe/duplicate-id-aria	on	2.0 A	4.1.2	parsing	critical	mechanical	IDs used in ARIA and labels must be unique
axe/empty-heading	on	best practice	none	name-role-value	minor	content	Headings should not be empty
axe/empty-table-header	on	best practice	none	name-role-value	minor	content	Table header text should not be empty
axe/form-field-multiple-labels	on	2.0 A	3.3.2	forms	moderate	mechanical	Form field must not have multiple label elements
axe/frame-focusable-content	on	2.0 A	2.1.1	keyboard	serious	mechanical	Frames with focusable content must not have tabindex=-1
axe/frame-title	on	2.0 A	4.1.2	text-alternatives	serious	content	Frames must have an accessible name
axe/frame-title-unique	on	2.0 A	4.1.2	text-alternatives	serious	content	Frames must have a unique title attribute
axe/heading-order	on	best practice	none	semantics	moderate	mechanical	Heading levels should only increase by one
axe/html-has-lang	on	2.0 A	3.1.1	language	serious	content	<html> element must have a lang attribute
axe/html-lang-valid	on	2.0 A	3.1.1	language	serious	content	<html> element must have a valid value for the lang attribute
axe/html-xml-lang-mismatch	on	2.0 A	3.1.1	language	moderate	mechanical	HTML elements with lang and xml:lang must have the same base language
axe/identical-links-same-purpose	off	2.0 AAA	2.4.9	semantics	minor	content	Links with the same name must have a similar purpose
axe/image-alt	on	2.0 A	1.1.1	text-alternatives	critical	content	Images must have alternative text
axe/image-redundant-alt	on	best practice	none	text-alternatives	minor	content	Alternative text of images should not be repeated as text
axe/input-button-name	on	2.0 A	4.1.2	name-role-value	critical	content	Input buttons must have discernible text
axe/input-image-alt	on	2.0 A	1.1.1, 4.1.2	text-alternatives	critical	content	Image buttons must have alternative text
axe/label	on	2.0 A	4.1.2	forms	critical	content	Form elements must have labels
axe/label-content-name-mismatch	on	2.1 A	2.5.3	semantics	serious	content	Elements must have their visible text as part of their accessible name
axe/label-title-only	on	best practice	none	forms	serious	content	Form elements should have a visible label
axe/landmark-banner-is-top-level	on	best practice	none	semantics	moderate	mechanical	Banner landmark should not be contained in another landmark
axe/landmark-contentinfo-is-top-level	on	best practice	none	semantics	moderate	mechanical	Contentinfo landmark should not be contained in another landmark
axe/landmark-main-is-top-level	on	best practice	none	semantics	moderate	mechanical	Main landmark should not be contained in another landmark
axe/landmark-no-duplicate-banner	on	best practice	none	semantics	moderate	mechanical	Document should not have more than one banner landmark
axe/landmark-no-duplicate-contentinfo	on	best practice	none	semantics	moderate	mechanical	Document should not have more than one contentinfo landmark
axe/landmark-no-duplicate-main	on	best practice	none	semantics	moderate	mechanical	Document should not have more than one main landmark
axe/landmark-one-main	on	best practice	none	semantics	moderate	mechanical	Document should have one main landmark
axe/landmark-unique	on	best practice	none	semantics	moderate	content	Landmarks should have a unique role or role/label/title (i.e. accessible name) combination
axe/link-in-text-block	on	2.0 A	1.4.1	color	serious	design	Links must be distinguishable without relying on color
axe/link-name	on	2.0 A	2.4.4, 4.1.2	name-role-value	serious	content	Links must have discernible text
axe/list	on	2.0 A	1.3.1	structure	serious	mechanical	<ul> and <ol> must only directly contain <li>, <script> or <template> elements
axe/listitem	on	2.0 A	1.3.1	structure	serious	mechanical	<li> elements must be contained in a <ul> or <ol>
axe/marquee	on	2.0 A	2.2.2	parsing	serious	mechanical	<marquee> elements are deprecated and must not be used
axe/meta-refresh	on	2.0 A	2.2.1	time-and-media	critical	mechanical	Delayed refresh under 20 hours must not be used
axe/meta-refresh-no-exceptions	off	2.0 AAA	2.2.4, 3.2.5	time-and-media	minor	mechanical	Delayed refresh must not be used
axe/meta-viewport	on	2.0 AA	1.4.4	sensory-and-visual-cues	moderate	mechanical	Zooming and scaling must not be disabled
axe/meta-viewport-large	on	best practice	none	sensory-and-visual-cues	minor	mechanical	Users should be able to zoom and scale the text up to 500%
axe/nested-interactive	on	2.0 A	4.1.2	keyboard	serious	manual	Interactive controls must not be nested
axe/no-autoplay-audio	on	2.0 A	1.4.2	time-and-media	moderate	manual	<video> or <audio> elements must not play automatically
axe/object-alt	on	2.0 A	1.1.1	text-alternatives	serious	content	<object> elements must have alternative text
axe/page-has-heading-one	on	best practice	none	semantics	moderate	content	Page should contain a level-one heading
axe/presentation-role-conflict	on	best practice	none	aria	minor	mechanical	Elements marked as presentational should be consistently ignored
axe/region	on	best practice	none	keyboard	moderate	mechanical	All page content should be contained by landmarks
axe/role-img-alt	on	2.0 A	1.1.1	text-alternatives	serious	content	[role=“img”] and [role=“image”] elements must have alternative text
axe/scope-attr-valid	on	best practice	none	tables	moderate	mechanical	scope attribute should be used correctly
axe/scrollable-region-focusable	on	2.0 A	2.1.1, 2.1.3	keyboard	serious	mechanical	Scrollable region must have keyboard access
axe/select-name	on	2.0 A	4.1.2	forms	critical	content	Select element must have an accessible name
axe/server-side-image-map	on	2.0 A	2.1.1	text-alternatives	minor	manual	Server-side image maps must not be used
axe/skip-link	on	best practice	none	keyboard	moderate	mechanical	The skip-link target should exist and be focusable
axe/summary-name	on	2.0 A	4.1.2	name-role-value	serious	content	Summary elements must have discernible text
axe/svg-img-alt	on	2.0 A	1.1.1	text-alternatives	serious	content	<svg> elements with an img or image role must have alternative text
axe/tabindex	on	best practice	none	keyboard	serious	mechanical	Elements should not have tabindex greater than zero
axe/table-duplicate-name	on	best practice	none	tables	minor	content	Tables should not have the same summary and caption
axe/target-size	on	2.2 AA	2.5.8	sensory-and-visual-cues	serious	design	All touch targets must be 24px large, or leave sufficient space
axe/td-headers-attr	on	2.0 A	1.3.1	tables	serious	mechanical	Table cell headers attributes must refer to other <th> elements in the same table
axe/th-has-data-cells	on	2.0 A	1.3.1	tables	serious	mechanical	Table headers in a data table must refer to data cells
axe/valid-lang	on	2.0 AA	3.1.2	language	serious	content	lang attribute must have a valid value
axe/video-caption	on	2.0 A	1.2.2	text-alternatives	critical	manual	<video> elements must have captions

Outside the default set

These rules run only where an override of the config names them by their IDs, since a criterion, a category or an engine reaches only the rules of the default set: axe-core calls them experimental or deprecated, or, as axe/frame-tested, they report what coverage already records.

Rule	Level	WCAG	Category	Severity	Fix class	Description
axe/aria-roledescription	2.0 A	4.1.2	aria	serious	mechanical	aria-roledescription must be on elements with a semantic role
axe/audio-caption	2.0 A	1.2.1	time-and-media	critical	manual	<audio> elements must have a captions track
axe/css-orientation-lock	2.1 AA	1.3.4	structure	serious	design	CSS Media queries must not lock display orientation
axe/duplicate-id	2.0 A, obsolete in 2.2	4.1.1	parsing	minor	mechanical	id attribute value must be unique
axe/duplicate-id-active	2.0 A, obsolete in 2.2	4.1.1	parsing	serious	mechanical	IDs of active elements must be unique
axe/focus-order-semantics	best practice	none	keyboard	minor	mechanical	Elements in the focus order should have an appropriate role
axe/frame-tested	best practice	none	structure	critical	manual	Frames should be tested with axe-core
axe/hidden-content	best practice	none	structure	minor	manual	Hidden content on the page should be analyzed
axe/landmark-complementary-is-top-level	best practice	none	semantics	moderate	mechanical	Aside should not be contained in another landmark
axe/p-as-heading	2.0 A	1.3.1	semantics	serious	mechanical	Styled <p> elements must not be used as headings
axe/table-fake-caption	2.0 A	1.3.1	tables	serious	mechanical	Data or header cells must not be used to give caption to a data table.
axe/td-has-header	2.0 A	1.3.1	tables	critical	mechanical	Non-empty <td> elements in larger <table> must have an associated table header