The Problem
Your web application fails Core Web Vitals on 40% of pages and has never been audited for WCAG compliance. The frontend team treats accessibility and performance as separate backlogs, but many of the same components cause both problems. A hero image without dimensions causes layout shift (CLS failure) and also lacks alt text (WCAG 1.1.1 failure). A modal that blocks the main thread for 400ms degrades INP and also traps keyboard focus (WCAG 2.1.2 failure).
The European Accessibility Act deadline is approaching, and Google Search Console shows declining organic traffic from CWV penalties. The team cannot afford to run a 3-week accessibility audit followed by a 2-week performance sprint. They need a unified approach that identifies which component fixes deliver improvements in both dimensions simultaneously.
The Solution
Use the accessibility-auditor and web-vitals-analyzer skills together to run a unified audit that flags both performance and accessibility issues per component, so a single code change can resolve violations in both categories at once.
Step-by-Step Walkthrough
1. Baseline both metrics on critical pages
Start with the five highest-traffic page templates to establish current scores across both dimensions:
Audit the accessibility and Core Web Vitals of these five page templates: src/pages/Home.tsx, src/pages/ProductDetail.tsx, src/pages/Checkout.tsx, src/pages/Search.tsx, and src/pages/Account.tsx. Report WCAG 2.2 Level AA violations alongside LCP, CLS, and INP scores for each page.
The combined report shows that ProductDetail has the worst overlap: LCP of 5.1s from an unoptimized hero image that also has no alt text, and CLS of 0.31 from a review widget that also traps keyboard focus. Checkout has 3 form fields missing labels (WCAG 3.3.2) and a payment button with 280ms INP from synchronous validation.
2. Identify overlapping fixes
Many issues share root causes across the two domains:
Cross-reference the accessibility violations with the Web Vitals failures. Show me which components appear in both reports and what single code change would fix both issues simultaneously.
The analysis identifies 8 components where a single fix addresses both an accessibility violation and a performance metric. The hero image fix alone -- adding dimensions, alt text, fetchpriority, and WebP format -- improves LCP by 2.4 seconds and resolves 3 WCAG violations. The modal refactor eliminates a keyboard trap while also reducing INP by 160ms.
3. Prioritize by combined impact score
Not all fixes are equal. Rank by combined severity to maximize the value of each engineering hour:
Create a prioritized fix list sorted by combined impact. Weight WCAG Critical violations and CWV failures that block the "Good" threshold highest. Include estimated time to fix for each item.
The result is a single backlog of 22 items. The top 5 fixes resolve 60% of accessibility violations and move 3 of 5 pages into "Good" CWV territory. Total estimated time: 6 hours for the top 5. Items 6-10 are accessibility-only fixes (form labels, ARIA attributes) that take minimal effort.
4. Implement fixes and verify both checks pass
After implementing the top-priority fixes, re-run the combined audit to confirm improvements:
Re-audit ProductDetail.tsx and Checkout.tsx after my changes. Confirm the WCAG violations are resolved and the Web Vitals scores now pass the "Good" thresholds. Flag any new issues introduced by the changes.
ProductDetail LCP drops from 5.1s to 1.8s, CLS from 0.31 to 0.04, and 9 of 11 WCAG violations are resolved. Checkout passes all three CWV metrics and has 2 remaining minor accessibility issues related to form error announcements that need aria-live regions.
5. Set up regression monitoring
Prevent future regressions by adding both checks to CI:
Add a CI check that runs both accessibility and performance audits on every PR that modifies frontend components. Fail the build if any new WCAG Critical violation is introduced or if any CWV metric regresses past the "Good" threshold.
The CI check runs in 90 seconds per page template and catches regressions before they reach production. A new developer adding a lazy-loaded hero image would be blocked before merge because the audit would flag the missing alt text and the CLS regression simultaneously.
Real-World Example
A SaaS company preparing for the European Accessibility Act deadline ran separate accessibility and performance audits on their 30-page application. The accessibility consultant found 67 violations. The performance engineer found 14 CWV failures.
When mapped together, 19 of the accessibility fixes and 8 of the CWV fixes overlapped on the same 12 components -- shared navigation, hero sections, modals, and form elements. By fixing those 12 components first, the team resolved 40% of accessibility violations and passed CWV on 80% of pages in a single sprint.
A navigation component that trapped keyboard focus also ran a synchronous resize listener causing 300ms INP. One refactor fixed both. The combined-first approach cut the total effort from an estimated 5 weeks to 3.5 weeks.