Accessibility Standards & SDLC Playbook

Governing Standards

Standard	Scope
WCAG 2.1 / 2.2 AA	Core web content accessibility criteria — primary baseline for most software products
Section 508 (US)	Federal procurement requirement; incorporates WCAG 2.0 AA by reference (501.1, 602.3)
EN 301 549 (EU)	European public sector procurement standard
WAI-ARIA 1.2	Roles / states / properties for custom interactive widgets
ADA Title III (US)	Legal exposure driver for public-facing commercial applications

Accessibility Across SDLC Phases

Phase	Activity
Requirements	Accessibility written in as a non-functional requirement (target: WCAG 2.1/2.2 AA); target assistive tech identified (NVDA/JAWS/VoiceOver, keyboard-only)
Design	Contrast ratios (4.5:1 text / 3:1 UI), focus order, no color-only meaning; ARIA intent annotated on mockups
Development	Implementation per Developer Scope of Work (see Scope tab)
Code Review	Accessibility checklist item enforced in every PR review
Testing	Automated + manual verification (see Tester Scope of Work) before merge/release
Release	VPAT / Accessibility Conformance Report (ACR) updated for customer-facing releases
Maintenance	Regression re-testing; accessibility defects tracked at the same severity as functional defects

Severity and Release Stopper are a program-level triage layer on top of WCAG — WCAG itself only defines conformance levels (A/AA), not urgency. Stopper = Critical: cannot ship regardless of deadline pressure. Ratings below are sensible defaults; adjust per where a defect actually lands (core flow vs. edge case).

Perceivable

SC	Level	Description	Default Severity	Stopper
1.1.1 Non-text Content	A	Alt text for images/icons/functional controls	Critical	Yes
1.2.1 Audio/Video-only (Prerecorded)	A	Text/audio alt for media-only content	Medium	—
1.2.2 Captions (Prerecorded)	A	Captions on recorded video	High	—
1.2.3 Audio Description or Alt	A	Audio description or full text alt for video	Medium	—
1.2.4 Captions (Live)	AA	Live captions	High	—
1.2.5 Audio Description (Prerecorded)	AA	Audio description for visual-only info in video	Medium	—
1.3.1 Info and Relationships	A	Structure conveyed programmatically, not just visually	Critical	Yes
1.3.2 Meaningful Sequence	A	Logical reading/navigation order	High	—
1.3.3 Sensory Characteristics	A	Instructions don't rely on shape/color/position alone	Medium	—
1.3.4 Orientation	AA	Not locked to one screen orientation	Medium	—
1.3.5 Identify Input Purpose	AA	Form fields identifiable for autofill	Medium	—
1.4.1 Use of Color	A	Color isn't the only info carrier	High	—
1.4.2 Audio Control	A	Auto-playing audio can be paused/muted	Medium	—
1.4.3 Contrast (Minimum)	AA	4.5:1 text contrast (3:1 large text)	High	—
1.4.4 Resize Text	AA	200% resize without breaking	Medium	—
1.4.5 Images of Text	AA	Real text over images of text	Low	—
1.4.10 Reflow	AA	Reflows at 400% zoom, no horizontal scroll	High	—
1.4.11 Non-text Contrast	AA	3:1 contrast for UI components/icons	Medium	—
1.4.12 Text Spacing	AA	No content loss with increased spacing	Low	—
1.4.13 Content on Hover or Focus	AA	Tooltips dismissible/hoverable/persistent	Medium	—

Operable

SC	Level	Description	Default Severity	Stopper
2.1.1 Keyboard	A	Full keyboard operability	Critical	Yes
2.1.2 No Keyboard Trap	A	Focus can always move away	Critical	Yes
2.1.4 Character Key Shortcuts	A	Single-key shortcuts remappable/disable-able	Medium	—
2.2.1 Timing Adjustable	A	Time limits adjustable/extendable	High	—
2.2.2 Pause, Stop, Hide	A	User can control auto-updating content	High	—
2.3.1 Three Flashes or Below Threshold	A	No seizure-triggering flashing	Critical	Yes
2.4.1 Bypass Blocks	A	Skip repeated content	Medium	—
2.4.2 Page Titled	A	Descriptive page titles	Low	—
2.4.3 Focus Order	A	Logical tab order	High	—
2.4.4 Link Purpose (In Context)	A	Link text/context makes destination clear	Medium	—
2.4.5 Multiple Ways	AA	More than one way to find a page	Low	—
2.4.6 Headings and Labels	AA	Descriptive headings/labels	Medium	—
2.4.7 Focus Visible	AA	Visible keyboard focus indicator	Critical	Yes
2.5.1 Pointer Gestures	A	Single-pointer alternative to multipoint gestures	High	—
2.5.2 Pointer Cancellation	A	Actions cancellable before completion	Medium	—
2.5.3 Label in Name	A	Visible label matches accessible name	High	—
2.5.4 Motion Actuation	A	Motion-triggered functions have UI alternative	Low	—

Understandable

SC	Level	Description	Default Severity	Stopper
3.1.1 Language of Page	A	Page language set programmatically	Medium	—
3.1.2 Language of Parts	AA	Language changes marked within content	Low	—
3.2.1 On Focus	A	No unexpected context change on focus	High	—
3.2.2 On Input	A	No unexpected context change on input	High	—
3.2.3 Consistent Navigation	AA	Nav order consistent across pages	Medium	—
3.2.4 Consistent Identification	AA	Same function labeled consistently	Medium	—
3.3.1 Error Identification	A	Errors identified and described in text	Critical	Yes
3.3.2 Labels or Instructions	A	Form fields have labels/instructions	Critical	Yes
3.3.3 Error Suggestion	AA	Fix suggestions provided where known	Medium	—
3.3.4 Error Prevention (Legal/Financial/Data)	AA	Review/confirm/reverse for critical submissions	High	—

Robust

SC	Level	Description	Default Severity	Stopper
4.1.1 Parsing	A	No major markup errors (deprecated in WCAG 2.2)	Low	—
4.1.2 Name, Role, Value	A	Correct AT exposure for custom widgets	Critical	Yes
4.1.3 Status Messages	AA	Status messages announced without focus	High	—

Revised Section 508 (2018)

Section	Description	Default Severity	Stopper
302 Functional Performance Criteria	High-level, technology-agnostic requirements (vision, hearing, speech, manipulation, cognitive)	Reference	—
Ch. 4 Hardware	Physical device requirements	N/A for software	—
501 Scope	Incorporates WCAG 2.0 AA by reference	Reference	—
502 Interoperability with AT	AT compatibility, object/role/value exposure	Critical	Yes
503 Applications	User prefs, alt UIs, caption/audio controls	High	—
504 Authoring Tools	Accessible content creation (if applicable)	Medium	—
602 Support Documentation	Docs describe/are themselves accessible	Medium	—
603 Support Services	Support channels accommodate disabilities	Medium	—

Grouped by Severity — All POUR + Section 508

Same criteria as above, re-sorted by triage bucket instead of principle — use this view to size the Critical/Stopper backlog at a glance.

Critical 10 criteria — all Release Stoppers

SC / Section	Principle	Level	Description	Stopper
1.1.1 Non-text Content	Perceivable	A	Alt text for images/icons/functional controls	Yes
1.3.1 Info and Relationships	Perceivable	A	Structure conveyed programmatically, not just visually	Yes
2.1.1 Keyboard	Operable	A	Full keyboard operability	Yes
2.1.2 No Keyboard Trap	Operable	A	Focus can always move away	Yes
2.3.1 Three Flashes or Below Threshold	Operable	A	No seizure-triggering flashing	Yes
2.4.7 Focus Visible	Operable	AA	Visible keyboard focus indicator	Yes
3.3.1 Error Identification	Understandable	A	Errors identified and described in text	Yes
3.3.2 Labels or Instructions	Understandable	A	Form fields have labels/instructions	Yes
4.1.2 Name, Role, Value	Robust	A	Correct AT exposure for custom widgets	Yes
502 Interoperability with AT	Section 508	—	AT compatibility, object/role/value exposure	Yes

High 16 criteria

SC / Section	Principle	Level	Description	Stopper
1.2.2 Captions (Prerecorded)	Perceivable	A	Captions on recorded video	—
1.2.4 Captions (Live)	Perceivable	AA	Live captions	—
1.3.2 Meaningful Sequence	Perceivable	A	Logical reading/navigation order	—
1.4.1 Use of Color	Perceivable	A	Color isn't the only info carrier	—
1.4.3 Contrast (Minimum)	Perceivable	AA	4.5:1 text contrast (3:1 large text)	—
1.4.10 Reflow	Perceivable	AA	Reflows at 400% zoom, no horizontal scroll	—
2.2.1 Timing Adjustable	Operable	A	Time limits adjustable/extendable	—
2.2.2 Pause, Stop, Hide	Operable	A	User can control auto-updating content	—
2.4.3 Focus Order	Operable	A	Logical tab order	—
2.5.1 Pointer Gestures	Operable	A	Single-pointer alternative to multipoint gestures	—
2.5.3 Label in Name	Operable	A	Visible label matches accessible name	—
3.2.1 On Focus	Understandable	A	No unexpected context change on focus	—
3.2.2 On Input	Understandable	A	No unexpected context change on input	—
3.3.4 Error Prevention (Legal/Financial/Data)	Understandable	AA	Review/confirm/reverse for critical submissions	—
4.1.3 Status Messages	Robust	AA	Status messages announced without focus	—
503 Applications	Section 508	—	User prefs, alt UIs, caption/audio controls	—

Medium 22 criteria

SC / Section	Principle	Level	Description	Stopper
1.2.1 Audio/Video-only (Prerecorded)	Perceivable	A	Text/audio alt for media-only content	—
1.2.3 Audio Description or Alt	Perceivable	A	Audio description or full text alt for video	—
1.2.5 Audio Description (Prerecorded)	Perceivable	AA	Audio description for visual-only info in video	—
1.3.3 Sensory Characteristics	Perceivable	A	Instructions don't rely on shape/color/position alone	—
1.3.4 Orientation	Perceivable	AA	Not locked to one screen orientation	—
1.3.5 Identify Input Purpose	Perceivable	AA	Form fields identifiable for autofill	—
1.4.2 Audio Control	Perceivable	A	Auto-playing audio can be paused/muted	—
1.4.4 Resize Text	Perceivable	AA	200% resize without breaking	—
1.4.11 Non-text Contrast	Perceivable	AA	3:1 contrast for UI components/icons	—
1.4.13 Content on Hover or Focus	Perceivable	AA	Tooltips dismissible/hoverable/persistent	—
2.1.4 Character Key Shortcuts	Operable	A	Single-key shortcuts remappable/disable-able	—
2.4.1 Bypass Blocks	Operable	A	Skip repeated content	—
2.4.4 Link Purpose (In Context)	Operable	A	Link text/context makes destination clear	—
2.4.6 Headings and Labels	Operable	AA	Descriptive headings/labels	—
2.5.2 Pointer Cancellation	Operable	A	Actions cancellable before completion	—
3.1.1 Language of Page	Understandable	A	Page language set programmatically	—
3.2.3 Consistent Navigation	Understandable	AA	Nav order consistent across pages	—
3.2.4 Consistent Identification	Understandable	AA	Same function labeled consistently	—
3.3.3 Error Suggestion	Understandable	AA	Fix suggestions provided where known	—
504 Authoring Tools	Section 508	—	Accessible content creation (if applicable)	—
602 Support Documentation	Section 508	—	Docs describe/are themselves accessible	—
603 Support Services	Section 508	—	Support channels accommodate disabilities	—

Low 7 criteria

SC / Section	Principle	Level	Description	Stopper
1.4.5 Images of Text	Perceivable	AA	Real text over images of text	—
1.4.12 Text Spacing	Perceivable	AA	No content loss with increased spacing	—
2.4.2 Page Titled	Operable	A	Descriptive page titles	—
2.4.5 Multiple Ways	Operable	AA	More than one way to find a page	—
2.5.4 Motion Actuation	Operable	A	Motion-triggered functions have UI alternative	—
3.1.2 Language of Parts	Understandable	AA	Language changes marked within content	—
4.1.1 Parsing	Robust	A	No major markup errors (deprecated in WCAG 2.2)	—

Tools Used for Developer Testing

eslint-plugin-jsx-a11y

Lint-time catch of missing alt text, labels, and ARIA misuse before code is even committed

axe-core (unit/CI)

Automated rule engine run in component tests or CI pipeline; blocks merge on critical/serious violations

axe DevTools (browser extension)

In-browser scan while building a feature — fastest feedback loop for a developer

Chrome Lighthouse

Built into DevTools; quick accessibility score + flagged issues during local dev

Storybook a11y addon

Per-component accessibility checks in isolation, useful in design-system-driven codebases

Colour Contrast Analyser / Stark

Verify contrast ratios against design tokens before/while implementing styles

Keyboard-only pass

No tool needed — unplug the mouse and tab through the feature before opening a PR

VoiceOver / NVDA spot-check

Quick screen reader smoke test on the specific component just built, not a full audit

Tools Used for QA / Tester Testing

axe DevTools / WAVE

Automated scanning across full pages/flows — catches roughly 30–40% of issues (contrast, missing labels, ARIA)

Lighthouse CI

Gated automated scan integrated into the release pipeline

Accessibility Insights for Web

Microsoft's guided manual + automated assessment tool for structured test passes

NVDA + Firefox/Chrome

Free screen reader — most common combination for Windows manual testing

JAWS + Edge/Chrome

Enterprise-standard screen reader, often required for federal/508 test evidence

VoiceOver + Safari (macOS/iOS)

Native Apple screen reader — required for mobile/web coverage on Apple platforms

TalkBack (Android)

Native Android screen reader for mobile web/app coverage

Colour Contrast Analyser

Verifies contrast across component states — hover, disabled, error, not just default

Siteimprove / Deque WorldSpace

Enterprise-scale continuous scanning and defect tracking across many pages/releases

Keyboard-only + zoom/reflow testing

Manual pass at 200%/400% zoom and full keyboard-only task walkthroughs

Developer Scope of Work

Use semantic HTML (button, nav, header, ordered headings) before reaching for ARIA
Add ARIA roles/labels only for custom widgets (tabs, modals, dropdowns) — no ARIA is better than bad ARIA
Ensure full keyboard operability: tab order, visible focus indicator, no keyboard traps
Manage focus programmatically — modals trap focus and return it on close; SPA route changes move focus
Provide text alternatives: alt text for images, labels for all form inputs, accessible names for icon-only buttons
Meet color contrast ratios in the actual implementation, not just the design file
Support text resize/zoom to 200% without loss of content or function
Announce dynamic content changes via aria-live regions where needed
Avoid time-based auto-updates without user control (carousels, session timeouts)
Fix accessibility defects flagged in code review or automated linting (eslint-plugin-jsx-a11y, axe-core in CI)

Tester Scope of Work

Automated scanning: axe DevTools, WAVE, Lighthouse, or axe-core in CI
Keyboard-only testing: full task flows using Tab/Shift+Tab/Enter/Esc/Arrow keys, no mouse
Screen reader testing: NVDA/JAWS on Windows, VoiceOver on macOS/iOS — verify reading order, announcements, form labels
Zoom/reflow testing: 200%/400% zoom, browser resize, no horizontal scroll or content clipping
Focus management testing: modals, dropdowns, route changes, error messages
Color/contrast verification: including hover, disabled, and error states, not just default
Regression testing: re-verify previously passing a11y criteria after each release
Reporting: log defects with WCAG success criterion reference (e.g. "1.4.3 Contrast Minimum"), severity, and repro steps
Sign-off: produce/update the VPAT/ACR or internal a11y test summary before the release gate

Shared Definition of Done

A feature isn't "done" until it passes automated scan (zero critical/serious issues), a keyboard-only walkthrough, and one screen reader smoke test — owned jointly by Dev (fix) and QA (verify).