Front-End-Checklist

Use when reviewing scripts, client components, bundles, or runtime behavior related to Minimize costly DOM read/write operations. Inspect both source code and the browser execution path so fixes target the real bottleneck or bug. In React, repeated requestAnimationFrame-driven state updates across multiple mounted components are a valid performance smell when visible in the source.

Use when applies to all HTML documents. Always check the very first line of the raw HTML source (view-source: or DevTools > Network > Response). In SSR frameworks, check the root HTML template (e.g., _document.tsx in Next.js, index.html in Vite/Vue, application.html.erb in Rails). The doctype is not a tag — it is a declaration and does not need a closing tag.

Use when reviewing rendered HTML, interactive components, or design-system patterns related to Wrap definition items in a definition list. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.

Use when auditing YMYL content pages for trust signals, generating disclaimer copy for medical or financial content, or reviewing affiliate disclosure requirements under FTC or ASA guidelines.

Use when reviewing templates, rendered HTML, or shared components related to Set text direction for RTL languages. Validate the final browser-facing markup, not just the source framework abstraction.

Use when reviewing image assets, markup, and CDN or build transforms related to Set explicit width and height on images. Check encoded size, rendered size, loading strategy, and above-the-fold impact together. Separate real CLS risks from tiny decorative SVGs or ornament-only assets that are unlikely to move surrounding content.

Use when reviewing a project's security posture, setting up CI pipelines, or responding to a reported vulnerability in a dependency.

Use when reviewing rendered HTML, interactive components, or design-system patterns related to Use correct definition list structure. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant.

Use when reviewing templates, rendered HTML, or shared components related to Load scripts with defer, async, or type=module. Validate the final browser-facing markup, not just the source framework abstraction.

Use when reviewing rendered HTML, interactive components, or design-system patterns related to Hide decorative elements from assistive technology. Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output where relevant. If an image is clearly decorative, default to no finding unless the snippet shows an actual issue such as broken semantics, focusability, or visible layout instability.

Use when reviewing scripts, client components, bundles, or runtime behavior related to Debounce and throttle event handlers. Inspect both source code and the browser execution path so fixes target the real bottleneck or bug.

Use when auditing a site's internal link graph for dead-end pages, suggesting related-content links to add to thin or standalone pages, or reviewing CMS templates that produce link-free content pages.

Use when reviewing form components, API payloads, or client-side storage to identify fields that are collected but not consumed by a stated feature.

Use when reviewing stylesheets, component styles, and responsive behavior related to Support dark mode with prefers-color-scheme. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when reviewing custom element class definitions or Web Component source code to check for missing ARIA reflection, keyboard handling, and form association.

Use when reviewing utility functions, component props, or template strings that format numbers, prices, or dates to check whether Intl APIs are used correctly.

Use when auditing slow page loads, heavy assets, or rendering delays related to Minimize cumulative layout shift. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.

Use when reviewing stylesheets, component styles, and responsive behavior related to Include a print stylesheet. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when reviewing stylesheets, component styles, and responsive behavior related to Order CSS files correctly. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when reviewing stylesheets, component styles, and responsive behavior related to Load CSS without blocking render. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when reviewing stylesheets, component styles, and responsive behavior related to Minify all CSS files. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when reviewing stylesheets, component styles, and responsive behavior related to Use CSS Grid for two-dimensional layouts. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when auditing slow page loads, heavy assets, or rendering delays related to Optimize CSS file size. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.

Use when reviewing stylesheets, component styles, and responsive behavior related to Use CSS custom properties for design tokens. Check the rendered layout across breakpoints and interaction states before proposing a fix.

Use when reviewing stylesheets, component styles, and responsive behavior related to Inline critical CSS for faster rendering. Check the rendered layout across breakpoints and interaction states before proposing a fix.