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Web Best Practices Audit

Applies modern web security, compatibility, and code-quality best practices based on Lighthouse's Best Practices audits.

Security & ReviewIntermediate★ 2,630⑂ 238AI score 8/10Last updated: Jun 14, 2026

What it does

  • Reviews security fundamentals: HTTPS/mixed content, CSP, Trusted Types, Subresource Integrity, security headers, secure cookies — all with ❌/✅ code pairs.
  • Flags browser compatibility issues: doctype, charset ordering, viewport meta, feature detection, safe polyfill strategy.
  • Calls out deprecated APIs (document.write, sync XHR, non-passive listeners) and memory-leak patterns.
  • Supplies a code-quality checklist: exposed production source maps, console errors, semantic HTML, image aspect ratios.

Who it's for

  • Frontend developers and agencies doing pre-launch reviews.
  • Anyone tasked with raising a Lighthouse "Best Practices" score.
  • Teams adopting CSP or Trusted Types for the first time.

Examples

  1. "Apply best practices to this project" → finds mixed content, vulnerable dependencies, and missing headers, then proposes fixes.
  2. "Run a security audit" → drafts a CSP header, recommends npm audit, adds SRI hashes to CDN scripts.
  3. "Modernize this legacy code" → replaces document.write and sync XHR with dynamic script loading and fetch, adds AbortController-based listener cleanup.

· · · Install guide · · ·

Try it now, no install

Paste this into Claude to use the skill without installing anything.

Read the instructions in this file and follow them to help me:
https://raw.githubusercontent.com/addyosmani/web-quality-skills/HEAD/skills/best-practices/SKILL.md

What I want: (describe your task here)

If Claude can't open the link, open it yourself and paste the contents instead.

↓ If it works for you, download the ZIP below and install it. Then it runs on its own — no pasting each time.

Install in the Claude app (no terminal)
  1. Download the ZIP with the button below.
  2. In Claude, open Settings → Capabilities and turn on 'Code execution and file creation'. (one time)
  3. Go to Customize → Skills → + → 'Upload a skill' and upload the ZIP.
↓ Download ZIP
Install in Claude Code

Let Claude do it — paste this into Claude Code

Install the skill I found on Claude Skill Mart.
Copy the skills/best-practices folder from the GitHub repo addyosmani/web-quality-skills into my ~/.claude/skills/best-practices/.
When it's done, tell me in one line what this skill can do.

Install with a command instead

git clone https://github.com/addyosmani/web-quality-skills.git && mkdir -p ~/.claude/skills && cp -r web-quality-skills/skills/best-practices ~/.claude/skills/

⚠ This is a third-party skill. Check the source repository before installing.

  1. Open a terminal.
  2. Clone the repo: git clone https://github.com/addyosmani/web-quality-skills.git
  3. Create the skills folder: mkdir -p ~/.claude/skills
  4. Copy the skill: cp -r web-quality-skills/skills/best-practices ~/.claude/skills/
  5. Restart Claude Code, then ask "run a security audit" or "apply best practices" to trigger it.
  6. (Optional) Also copy the web-quality-audit skill from the same repo so the cross-reference link resolves.
View source on GitHub ↗License: MIT