seo

name	seo
description	Use when writing, reviewing, or optimizing blog posts, landing pages, meta tags, titles, descriptions, headings, URLs, or any user-facing web content for search engines. Triggers on SEO questions, content audits, structured data, Open Graph tags, schema markup, or on-page optimization. Also use for German-language SEO specifics (umlauts, hreflang, Flesch DE).

On-Page SEO — Blog & Content Reference

Concrete limits, rules, and checklists for on-page SEO. All numbers reflect Google's current SERP rendering (2025-2026).

Title Tag

Property	Limit	Notes
Desktop pixel width	580 px (max ~600 px)	Proportional font — W/M wider than i/l
Mobile pixel width	~920 px (smaller font)	More room on mobile
Character guideline	50-60 characters	Covers ~90% of desktop SERPs
Keyword placement	Primary keyword near the beginning	Natural language, no keyword stuffing
Uniqueness	One unique title per page	Never duplicate across pages
Brand	Append brand after separator if space allows	Primary Keyword — Brand

Quick check: If your title exceeds 55 characters, verify pixel width with a SERP preview tool.

Meta Description

Property	Limit	Notes
Desktop pixel width	~920 px
Desktop characters	150-160 characters	Google sometimes shows up to 300
Mobile characters	~120 characters	Shorter display on mobile
Safe cross-device	120-158 characters	Most important message within first 120
Focus keyword	Must appear in the description	Natural einbauen, nicht erzwingen
CTA	Include a call-to-action	"Jetzt lesen", "Erfahre mehr"
Uniqueness	One unique description per page	Never duplicate

Rule: Front-load the value proposition into the first 120 characters — everything after may be truncated on mobile.

Heading Structure (H1-H6)

Rule	Detail
One H1 per page	Contains primary keyword naturally; describes core topic
Sequential nesting	H1 → H2 → H3 → H4; never skip levels (no H1 → H3)
H2 = major sections	Secondary keywords and semantically related terms
H3 = subsections	Break down H2 sections into granular detail
No styling abuse	Never use heading tags for visual styling; use CSS classes
Subheading distribution	Max 300 words between two subheadings; long text blocks without heading kill readability and SEO

URL / Slug

Rule	Detail
Length	3-5 words (~50-60 characters)
Separator	Hyphens (-), never underscores
Case	Always lowercase
Keyword	Main keyword at the beginning
No dates	/blog/seo-leitfaden/ not /blog/2026/03/seo-leitfaden/
Depth	Max 2-3 levels; avoid deep nesting
Umlauts	Replace: ä→ae, ö→oe, ü→ue, ß→ss (never just drop the dots)
Stop words	Remove unnecessary filler words (und, der, die, das)

Image SEO

Rule	Detail
Alt text length	80-140 characters (5-15 words)
Alt text content	Descriptive, keyword-relevant, unique per image
Decorative images	alt="" (empty, not omitted)
File naming	Descriptive, hyphen-separated: blaues-leder-etui.webp not IMG_4521.jpg
Format priority	AVIF → WebP → JPEG/PNG fallback; use <picture> element
Dimensions	Always set width and height attributes (prevents CLS)
Lazy loading	loading="lazy" for below-fold; loading="eager" + fetchpriority="high" for hero/LCP
Responsive	Use srcset for responsive serving

Internal Linking

Rule	Detail
Density	2-5 contextual links per 1,000 words
Total per page	Keep under 150 links
Click depth	Key pages within 3 clicks of homepage
Anchor text	Descriptive, varied; mix exact-match and topically related
Outbound links	1-2 autoritäre externe Links pro Beitrag (Quellenangaben, Referenzen)
Topic clusters	Pillar pages + supporting content
Orphan pages	Jede Seite braucht mind. einen internen Link, der auf sie zeigt
Table of contents	Add for posts >1,000 words; anchor links matching H2/H3

Content Structure & Length

Content Type	Word Count
Quick-answer post	300-500 words
Standard blog post	1,500-2,500 words
How-to guide	1,700-2,500 words
Pillar / ultimate guide	3,000-5,000+ words

Rule	Detail
Featured snippets	Answer-first: direct answer in 40-60 words right after the heading
List snippets	6-10 items for list snippets
Table snippets	4-6 columns, 5-10 rows
Early content	44% of AI citations come from the first 30% of page content
Keyword in first paragraph	Focus keyword must appear within the first 10% of the text (ideally first sentence)
Keyword density	1-2% as rough guideline; focus on natural language, not frequency
Keyword cannibalization	Each post targets a unique focus keyword — never optimize two pages for the same keyword
Thin content	Pages with <300 words are flagged as thin content by Google; always exceed this minimum
Readability (DE)	Flesch-Index 50-60 for German texts (see German SEO section)
Passive voice	Max 10% passive sentences; active voice ranks and reads better
Transition words (DE)	Mind. 30% der Sätze mit Übergangswörtern (allerdings, deshalb, beispielsweise, daher, außerdem)

Open Graph & Social Meta Tags

Tag	Specification
og:title	Under 60 characters
og:type	"article" for blog posts
og:image	1200×630 px (1.9:1); JPEG/PNG; absolute HTTPS URL
og:url	Canonical URL of the page
og:description	130-160 characters (safe range)
og:image:alt	Required if og:image is set
twitter:card	"summary_large_image"

OG uses property attribute, Twitter uses name attribute. Set both and keep in sync.

Canonical URL

Rule	Detail
Self-referencing	Every page gets a self-referencing canonical, even without duplicates
Absolute URLs	Always use full https:// URLs
One per page	Multiple canonicals cause confusion
Paginated pages	Each page gets its own self-referencing canonical

XML Sitemap

Rule	Detail
Blog posts	Every published blog post must be included in the XML sitemap
lastmod	Set <lastmod> to the actual last modification date (ISO 8601)
Excluded pages	noindex pages, redirects, and error pages must NOT be in the sitemap
Auto-generation	Use CMS or plugin to auto-generate; never maintain manually
Submit	Reference sitemap in robots.txt via Sitemap: https://example.de/sitemap.xml

Content Freshness

Rule	Detail
"Zuletzt aktualisiert"	Visible date on the page when content was last reviewed
dateModified	Must match the visible date in Schema.org JSON-LD
Review cycle	Audit content at least annually; YMYL topics more frequently
Outdated statistics	Update numbers, percentages, and year references when refreshing

Schema.org / Structured Data (BlogPosting)

Use BlogPosting type with JSON-LD format for blog content:

{
    "@context": "https://schema.org",
    "@type": "BlogPosting",
    "headline": "Titel des Beitrags",
    "image": [
        "https://example.de/bild-16x9.webp",
        "https://example.de/bild-4x3.webp",
        "https://example.de/bild-1x1.webp"
    ],
    "datePublished": "2026-06-04T10:00:00+02:00",
    "dateModified": "2026-06-04T12:00:00+02:00",
    "author": {
        "@type": "Person",
        "name": "Autorenname",
        "url": "https://example.de/ueber-uns/"
    },
    "publisher": {
        "@type": "Organization",
        "name": "Firmenname",
        "url": "https://example.de/"
    }
}

Property	Notes
headline	Same as title tag content
image	Multiple aspect ratios (1x1, 4x3, 16x9); min 1200 px wide
datePublished / dateModified	ISO 8601 with timezone
author.url	Link to author bio page (strongly recommended)

Additional Schema Types

BreadcrumbList

Use on every page for navigation path display in SERPs:

{
    "@context": "https://schema.org",
    "@type": "BreadcrumbList",
    "itemListElement": [
        { "@type": "ListItem", "position": 1, "name": "Blog", "item": "https://example.de/blog/" },
        { "@type": "ListItem", "position": 2, "name": "SEO Leitfaden", "item": "https://example.de/blog/seo-leitfaden/" }
    ]
}

FAQPage

Use when the post contains a dedicated FAQ section with question-answer pairs:

{
    "@context": "https://schema.org",
    "@type": "FAQPage",
    "mainEntity": [
        {
            "@type": "Question",
            "name": "Wie lang sollte ein Title-Tag sein?",
            "acceptedAnswer": { "@type": "Answer", "text": "50-60 Zeichen bzw. max 580 Pixel Breite." }
        }
    ]
}

Combine multiple schema types on one page by wrapping them in a @graph array.

E-E-A-T Signals

Dimension	How to Signal
Experience	Author bios, original photos, real examples, first-person accounts
Expertise	Niche-focused depth, credentials, structured explanations
Authoritativeness	Original research, industry recognition, authoritative backlinks
Trustworthiness	Named bylines with bio links, accurate sources, "zuletzt geprüft" dates
AI content	Must be reviewed by SME, enriched with original insights, attributed to named author

Core Web Vitals

Metric	Good	What it measures
LCP	≤ 2.5 s	Largest Contentful Paint — loading speed
INP	≤ 200 ms	Interaction to Next Paint — responsiveness
CLS	≤ 0.1	Cumulative Layout Shift — visual stability

Mobile-First

Rule	Detail
Content parity	Identical content, meta tags, structured data on mobile and desktop
Touch targets	Minimum 48×48 CSS px; 8 px spacing between targets
Viewport meta	Required: <meta name="viewport" content="width=device-width, initial-scale=1">
Page speed	53% of mobile users leave if page takes >3 seconds

Robots Meta

Directive	Effect
index, follow	Default; no need to specify
noindex	Page removed from index (must allow crawling for Google to see tag)
max-snippet:[n]	Limit snippet to N characters
max-image-preview:large	Allow large image previews in SERPs

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German SEO Specifics

Umlauts in URLs

Character	URL replacement
ä	ae
ö	oe
ü	ue
ß	ss

Google treats "ue" the same as "ü" for keyword matching. Never just drop the dots (ü→u is wrong).

Flesch-Index (German Adaptation — Amstad 1978)

Formula: 180 - SL - (58.5 × WL) (SL = sentence length in words, WL = avg syllables per word)

Score	Interpretation
60-70	Gut lesbar für breites Publikum
50-60	Empfohlen für SEO-Texte (YOAST)
30-50	Anspruchsvoll, Fachpublikum
0-30	Wissenschaftlich/technisch

German words are inherently longer (compound nouns), so scores are naturally lower than English.

Hreflang (DACH)

Tag	Market
hreflang="de-DE"	Germany
hreflang="de-AT"	Austria
hreflang="de-CH"	Switzerland
hreflang="de"	Language-only fallback
hreflang="x-default"	Fallback for non-matching users

Requirements: Bidirectional linking (all versions link to all others + self); absolute URLs; all return HTTP 200.

Legal Requirements (Trust Signals)

German sites require Impressum and Datenschutzerklärung — both affect trust signals and are legally mandatory.

Domain & Market

• .de ccTLD provides strong geo-targeting signal for Germany
• Google.de has ~90%+ market share in Germany
• "Sie" vs "du" — consistency matters; trend 2025-2026 is "du" for B2C

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Verlinkung mit Copywriter-Skills

Beim Schreiben von Texten gelten SEO-Limits UND Tonalitätsregeln gemeinsam:

Textart	Zusätzlich laden
Technische Blogbeiträge, Produkttexte, Feature-Ankündigungen	copywriter-de
Landing Pages, Service-Seiten, Booking-Seiten, Sales Copy	marketing-copywriter-de

Kein Widerspruch: Die Copywriter-Skills bestimmen Stimme, Rhythmus und Struktur. Dieser Skill bestimmt die technischen Limits (Zeichenlängen, Pixel, Heading-Hierarchie, Schema). Beide ergänzen sich.

Wichtig: Die H1 auf der Seite darf emotionaler und länger sein als der Title-Tag. Der Title-Tag ist für die SERPs optimiert (50-60 Zeichen), die H1 für den Leser auf der Seite.

Blog Post SEO Checklist

Use this checklist when writing or reviewing a blog post:

Content & Keywords:

• Focus keyword appears in title, H1, meta description, URL slug, and first paragraph
• Focus keyword is unique to this post (no keyword cannibalization)
• Keyword density 1-2%, naturally distributed
• Content length appropriate for type (see table above), minimum 300 words
• Featured snippet paragraph (40-60 words) after key heading

Structure & Readability:

• One H1 per page, heading hierarchy sequential (H1→H2→H3)
• Max 300 words between subheadings
• Flesch-Index 50-60 for German texts
• Max 10% passive voice
• Mind. 30% of sentences with transition words
• Sentence length varies visibly

Meta & SERP:

• Title: 50-60 characters, primary keyword near beginning, ≤580 px
• Meta description: 120-158 characters, focus keyword included, CTA, value in first 120 chars
• URL/slug: 3-5 words, lowercase, hyphens, keyword first, umlauts replaced
• Canonical URL: Self-referencing, absolute HTTPS

Links:

• Internal links: 2-5 per 1,000 words, descriptive anchor text
• Outbound links: 1-2 authoritative external sources
• No orphan pages — at least one internal link points to this post
• Table of contents for posts >1,000 words

Images:

• Alt text (80-140 chars), descriptive filenames, keyword-relevant
• WebP/AVIF format, width/height attributes set
• Hero image: loading="eager" + fetchpriority="high"; rest: loading="lazy"

Technical:

• Schema.org: BlogPosting JSON-LD with headline, image, dates, author, publisher
• Schema.org: BreadcrumbList JSON-LD for navigation path
• Schema.org: FAQPage JSON-LD if post contains FAQ section
• Open Graph: og:title, og:description, og:image (1200×630), og:type="article"
• XML Sitemap: Post included with correct <lastmod>
• Content freshness: "Zuletzt aktualisiert" date visible + dateModified in Schema

E-E-A-T:

• Author byline with bio link
• Specific claims backed by data or sources
• "Zuletzt aktualisiert" date visible on page
• Impressum and Datenschutzerklärung accessible

Mobile:

• Content parity with desktop
• Touch targets ≥48 px, viewport meta set
• Page load <3 seconds on mobile

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Sources

This skill was compiled from the following references (2025-2026):

Google Official:

• Google Search Central — Article Structured Data
• Google Search Central — URL Structure
• Google Search Central — Mobile-First Indexing
• Google Search Central — Helpful Content
• Google Search Central — Hreflang
• Google Search Central — Google Images Best Practices

Title & Meta:

• Zyppy — Meta Title Tag Length
• Search Engine Land — Title Tag Length
• The Ocean Marketing — Title Tag Length Best Practices
• Scalenut — Meta Title Length Best Practices 2026
• MRS Digital — Meta Length Checker

Content & Readability:

• SEO.co — Content Length
• Lovable.dev — Blog Post Length Guide
• Yoast — Flesch Reading Ease Score
• Yoast — How to Use Headings
• Conductor — Headings for SEO

URL & Slug:

• Slug Genius — URL Slug Best Practices
• Shopify — SEO-Friendly URLs

Structured Data:

• Search Engine Zine — Article vs Blog Schema
• Open Graph Protocol
• Ahrefs — Open Graph Meta Tags

Image SEO:

• AltText.ai — Image Alt Text SEO Best Practices
• Digital Applied — Image SEO Guide 2026

Internal Linking:

• Upward Engine — Internal Linking Best Practices
• Traffic Think Tank — Internal Linking

Core Web Vitals:

• CoreWebVitals.io
• Mewa Studio — SEO Core Web Vitals 2026

E-E-A-T:

• BKND Development — EEAT SEO Strategy 2026
• Search Engine Land — Google E-E-A-T for SEO

German SEO:

• WebCertain — Umlauts in German SEO
• Nikolai Sroka — Flesch Index Lesbarkeit
• Seokratie — SEO-Faktor Lesbarkeit
• Outreach Monks — Hreflang SEO

Existing Claude Code SEO Skills (inspiration):

• AgriciDaniel/claude-seo
• aaron-he-zhu/seo-geo-claude-skills
• aevans-eng/seo-skill