# SEO Optimization > SEO — on-page, technical, structured data, Core Web Vitals, and mobile-first indexing. Use when optimizing a website for search engines, adding meta tags or structured data, fixing Core Web Vitals, or auditing technical SEO. - Skill: `projectious-work/seo-optimization-2` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add projectious-work/seo-optimization-2` - Raw SKILL.md: https://api.skillmd.com/api/skills/projectious-work/seo-optimization-2/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Marketing & Growth - Author: projectious-work (https://skillmd.com/u/projectious-work) - Updated: 2026-09-21 - Page: https://skillmd.com/skills/projectious-work/seo-optimization-2 --- # SEO Optimization ## Intro SEO is two jobs: make the page understandable to crawlers (titles, headings, structured data, sitemap, canonicals) and make it fast and usable for humans (Core Web Vitals, mobile, HTTPS). Both feed the same ranking signals. ## Overview ### On-page SEO - **Title tags:** unique per page, 50–60 characters, primary keyword near the start. - **Meta descriptions:** 120–160 characters, with a call to action, unique per page. - **Headings:** one `

` per page matching the topic; logical `

`–`

` hierarchy without skipping levels. - Alt text: descriptive, concise (≤125 chars), keywords used naturally. Decorative images use `alt=""`. - Internal links: descriptive anchor text — never "click here". - URLs: short, lowercase, hyphen-separated, include the primary keyword. - Content: answer the user's query comprehensively; use related terms naturally rather than keyword-stuffing. ### Crawling and indexing - robots.txt at the site root: allow important paths, block admin and staging. - XML sitemap lists all indexable pages, excludes `noindex` pages, submitted to Search Console. - Canonicals on every page (``) to prevent duplicate content. - Hreflang for multilingual sites (`` per language) with a self-referencing entry and `x-default`. - HTTP status codes: 200 for live, 301 for permanent redirects, 404 for gone. No soft 404s. - Redirect chains: at most one hop. Fix chains to point directly to the final URL. - Index control: `` on pages that should not rank. ### Structured data (JSON-LD) - Use JSON-LD in `