What are the six layers of technical SEO?

Crawlability (can engines access the URLs), indexability (which crawlable URLs should be indexed), rendering (does the rendered HTML match what crawlers see), site architecture (is the site structured for users and crawlers), structured data and signals (does the site speak crawler language), and page experience and security (does it meet the baseline). They stack: a failure in a lower layer breaks everything above it, so the audit scores them bottom-up.

What is the difference between crawlability and indexability?

Crawlability is whether search engines can access the URLs at all: robots.txt does not block important paths, it does not disallow CSS or JS (which would break rendering), the sitemap returns 200 and lists canonical URLs only, and crawl budget is not wasted on endless faceted-nav URLs. Indexability is which of the crawlable URLs should be indexed: one canonical URL per piece of content, self-referencing canonicals, noindex on staging, search, filter, and thank-you pages, and no mixed signals where the canonical points one way, the sitemap another, and internal links a third.

How do I handle a site migration?

With a redirect map, because migrating without one is the single biggest cause of post-migration traffic loss. The technical audit produces a redirect map as a CSV alongside the report, and the migration checklist covers the pre and post-launch steps. For the full discipline (inventory, audit decisions, cutover, and the 30-to-90-day recovery window) pair this skill with content-migration, which owns the end-to-end move.

Why check rendering for a JavaScript site?

Because the rendered HTML is what crawlers index, and for single-page apps it can diverge from what the framework ships. Confirm that Googlebot sees the rendered content using the URL Inspection tool, keep critical content out of client-side-only rendering or server-render it, give lazy-loaded content proper loading attributes, and watch for hydration errors that strip content from the rendered DOM. Many AI crawlers render even less reliably than Googlebot, so server-rendered critical content helps there too.

Are Core Web Vitals the main ranking signal?

No. Page experience matters, but it does not override relevance, so treating Core Web Vitals as the only ranking lever is a mistake. They sit in the page-experience layer alongside HTTPS with no mixed content, HSTS, mobile-friendliness, and correct 404 handling. A fast page with weak relevance still will not rank; the vitals are a baseline to meet, not a substitute for the content and authority above them.

Skill · Technical SEO

Technical SEO.

Audit how search engines crawl, render, index, and trust a site.

Audit and fix the layer beneath the content: how search engines crawl, render, index, and trust a site. Technical SEO has six layers, stacked, and a failure in a lower layer breaks everything above it. The audit works bottom-up, from crawlability and indexability through architecture, structured data, and page experience.

It is for site-wide issues, not single pages: a migration check, an indexing drop, a new site's foundations, or crawl waste. The highest-risk scenario is migration, where a missing redirect map is the biggest cause of lost traffic.

Audience: SEO and engineering teams auditing a site before or after a migration, investigating indexing or ranking drops, or setting up SEO foundations.

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The framework

Six layers, stacked bottom to top.

A failure in a lower layer breaks everything above it, so the audit works from the bottom up.

01Crawlability: can engines access the URLs? robots.txt does not block important paths or CSS and JS, the sitemap returns 200 with canonical URLs only, and crawl budget is not wasted on low-value URLs.
02Indexability: of the crawlable URLs, which should be indexed? One canonical per piece of content, noindex on staging and filter and thank-you pages, and no mixed signals between canonical, sitemap, and internal links.
03Rendering: does the rendered HTML match what crawlers see? Critical content visible without JavaScript or properly server-rendered, no cloaking, and hydration errors that do not strip content from the DOM.
04Site architecture: important pages reachable in 3 clicks or fewer, internal links distributing authority logically, no orphan pages, no redirect chains, and no 4xx on internally linked URLs.
05Structured data and signals: Schema.org markup in JSON-LD on appropriate page types, validated, with Organization, BreadcrumbList, and author and publisher schema linked correctly.
06Page experience and security: HTTPS with no mixed content, HSTS, Core Web Vitals within thresholds, mobile-friendly, and 404 pages that return 404 rather than a soft 200.

The discipline

Indexability before content, redirect map before migration.

The six layers stack, so the audit works bottom-up. A page that cannot be crawled cannot be indexed, and a page that is not indexed cannot rank however good its content, which is why crawlability and indexability come before architecture, schema, and page experience.

Check indexability before any content work, because optimizing rankings on a noindexed page is wasted. The most damaging mistakes are quiet ones: an over-aggressive robots.txt blocking CSS or JS (which breaks Google's rendering), a sitemap full of duplicate URLs (worse than no sitemap), and canonical tags treated as directives when content has actually moved and needs a redirect.

Migration is the highest-risk scenario. Migrating without a redirect map is the single biggest cause of post-launch traffic loss, so the audit produces one as a CSV alongside the report, and the work pairs with the content-migration skill that owns the full cutover discipline.

Reference files

Two references that go alongside the SKILL.md.

references/audit-template.md
A fillable technical SEO audit template.
references/migration-checklist.md
A pre and post-migration checklist covering the highest-risk scenario.

Browse all reference files on GitHub

Bridges to other skills

The skills around the technical layer.

Technical SEO is the foundation. These cover single-page work, the content above it, the migration it most often supports, and the audit that triages its findings.

Single-page work
seo-onpage
Once the technical foundation is sound, optimizing an individual page's titles, headers, and content is on-page work. This skill makes sure that page can be indexed at all.
Triage by impact
seo-site-health-audit
Takes crawl findings and triages them by SEO impact rather than raw severity. Technical SEO is the strategy and schema design; that skill prioritizes what to fix first.
The cutover
content-migration
Owns the full URL map, cutover, and recovery for a move. The technical audit's migration checklist feeds it; the two run together on a replatform.
Speed in depth
performance-optimization
Pure performance work beyond the SEO context (bundle size, render cost) lives there. Technical SEO treats Core Web Vitals as one page-experience signal, not the whole job.
What to plan
seo-keyword
Keyword strategy and content planning is a separate front of the work. The technical layer makes a site rankable; research decides what it should rank for.

Open source under MIT

Read the SKILL.md on GitHub.

The skill source lives in the rampstackco/claude-skills repository alongside dozens of other skills covering the full lifecycle of brand and product work. This page is a structured overview; the SKILL.md is the source. MIT licensed.

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Frequently asked questions.

What are the six layers of technical SEO?: Crawlability (can engines access the URLs), indexability (which crawlable URLs should be indexed), rendering (does the rendered HTML match what crawlers see), site architecture (is the site structured for users and crawlers), structured data and signals (does the site speak crawler language), and page experience and security (does it meet the baseline). They stack: a failure in a lower layer breaks everything above it, so the audit scores them bottom-up.
What is the difference between crawlability and indexability?: Crawlability is whether search engines can access the URLs at all: robots.txt does not block important paths, it does not disallow CSS or JS (which would break rendering), the sitemap returns 200 and lists canonical URLs only, and crawl budget is not wasted on endless faceted-nav URLs. Indexability is which of the crawlable URLs should be indexed: one canonical URL per piece of content, self-referencing canonicals, noindex on staging, search, filter, and thank-you pages, and no mixed signals where the canonical points one way, the sitemap another, and internal links a third.
How do I handle a site migration?: With a redirect map, because migrating without one is the single biggest cause of post-migration traffic loss. The technical audit produces a redirect map as a CSV alongside the report, and the migration checklist covers the pre and post-launch steps. For the full discipline (inventory, audit decisions, cutover, and the 30-to-90-day recovery window) pair this skill with content-migration, which owns the end-to-end move.
Why check rendering for a JavaScript site?: Because the rendered HTML is what crawlers index, and for single-page apps it can diverge from what the framework ships. Confirm that Googlebot sees the rendered content using the URL Inspection tool, keep critical content out of client-side-only rendering or server-render it, give lazy-loaded content proper loading attributes, and watch for hydration errors that strip content from the rendered DOM. Many AI crawlers render even less reliably than Googlebot, so server-rendered critical content helps there too.
Are Core Web Vitals the main ranking signal?: No. Page experience matters, but it does not override relevance, so treating Core Web Vitals as the only ranking lever is a mistake. They sit in the page-experience layer alongside HTTPS with no mixed content, HSTS, mobile-friendliness, and correct 404 handling. A fast page with weak relevance still will not rank; the vitals are a baseline to meet, not a substitute for the content and authority above them.