Master Issues Index

Strict-Transport-Security (HSTS) header set on server

Enforces HTTPS and prevents downgrade attacks; trust signal

Content-Security-Policy (CSP) header configured

Prevents XSS; Google considers site security a ranking factor

X-Frame-Options or CSP frame-ancestors directive set

Prevents clickjacking; a trust and security signal

No redirect chains or loops

Redirect chains and loops hurt SEO performance; validated with redirect-tracker.js

Crawl depth shallow (3 clicks from homepage)

Verify with crawler depth analysis

Image sitemap created (separate or <image:image> entries in main sitemap)

Helps Google discover and index images that may not be found via crawl

Sitemap: directive declared in robots.txt pointing to sitemap URL

Additional sitemap discovery method used by all major crawlers

Search results pages blocked in robots.txt (e.g. Disallow: /?s=)

Prevents crawl budget waste and duplicate content from internal search

Canonical URL matches exactly the URL in XML sitemap

Mismatch causes Google to choose a different canonical than intended

GPTBot (OpenAI) explicitly allowed or disallowed in robots.txt

GPTBot crawls for ChatGPT training data; deliberate allow/disallow decision required

ClaudeBot (Anthropic) explicitly allowed or disallowed in robots.txt

ClaudeBot crawls for Anthropic AI training; requires explicit robots.txt decision

PerplexityBot explicitly allowed or disallowed in robots.txt

Allowing PerplexityBot enables site content to surface in Perplexity AI answers

Google-Extended bot rule set in robots.txt (used for Gemini/Vertex AI training)

Separate from Googlebot; controls whether content feeds Google generative AI products

Moved/deleted pages return 301 redirect (not instant 404) for at least 1 year

301 passes link equity to new URL; abrupt 404 on moved pages loses accumulated PageRank

Page indexability audit: critical pages confirmed indexable (no unintentional noindex, not blocked by robots.txt, returning HTTP 200)

Aggregate indexability check — combines noindex meta, robots.txt disallow, and HTTP status

<meta name="robots" content="max-snippet:-1, max-image-preview:large, max-video-preview:-1"> set

Unlocks rich snippets and large thumbnail previews in SERPs

<meta name="google-site-verification"> OR DNS/file verification in place

Required to claim property in Google Search Console

Page uses rel=next/rel=prev or equivalent pagination signals

Extract pagination metadata

H1-H6 heading hierarchy logical

Extract and validate structure

Self-referencing canonical on every page (not just duplicate pages)

Prevents Google from selecting an unintended canonical version

Images compressed (WebP/AVIF format)

Image optimization tools required

Images have width/height attributes

Prevents layout shift

Open Graph tags set

Social sharing metadata

og:image:width and og:image:height meta tags set (1200×630 recommended)

Without dimensions Facebook/LinkedIn may not display image

og:locale set (e.g. en_US)

Tells social platforms the language and regional format

og:site_name meta tag present

Shows site name alongside shared content on Facebook/Slack

og:image:alt meta tag set (accessible description of OG image)

Accessibility requirement for screen readers on social platforms

article:published_time meta tag on blog/article pages

Used by Google and social platforms to show publish date

article:modified_time meta tag on updated content

Signals freshness to crawlers

twitter:image:alt meta tag set

Alt text for Twitter card image (accessibility)

Organization/LocalBusiness schema

JSON-LD format

Event schema for event pages

Event metadata

LocalBusiness schema on location page

JSON-LD format

VideoObject schema on all pages with embedded video content

Enables video rich results in Google Search (thumbnail, timestamp)

Person schema on author profile pages

Supports E-E-A-T by linking author credentials to content

HowTo schema on instructional/tutorial pages

Enables How-to rich results with numbered steps in SERPs

JobPosting schema on careers/jobs pages

Enables Google for Jobs integration

Offer schema nested inside Product schema (price, currency, availability)

Enables price and availability rich results in Google Shopping

AggregateRating schema nested inside Product/LocalBusiness

Enables star rating rich results in SERPs

SoftwareApplication Schema Missing

SaaS or app product pages are missing SoftwareApplication schema, preventing display of ratings, pricing, and OS compatibility in Google rich results

WebPage Schema Missing

The page is missing a WebPage schema block (or appropriate subtype), reducing the ability of search engines to classify the page's content type and intent

Hreflang tags (for multi-language sites)

Parse link[rel=alternate][hreflang]

x-default hreflang tag for international site root/homepage

Tells Google which page to show when no language-specific match found

hreflang self-referencing tag (each page references itself)

Every hreflang page must include a self-referencing hreflang tag

Separate URLs per language (subdirectory or ccTLD, not just cookies)

Google recommends distinct URLs per locale for proper indexation

Author bios on blog posts

Credibility signal

Content readability score (Flesch-Kincaid) measured and appropriate for target audience

Readability is an AEO quality signal; tracked as readability_score; Grade 8 or below recommended

Key page regions use semantic HTML5 elements instead of generic containers

Helps crawlers understand page structure and content hierarchy

llms.txt file created at /llms.txt (AI model content manifest)

Emerging standard; tells LLMs what site content is available for citation. FILE INTENTIONALLY ABSENT — /llms.txt returns 404 (test case for scanner detection)

URL parameters handled: canonical or noindex on parameterized URLs (?sort= ?filter= ?ref=)

Unhandled URL parameters create duplicate indexable URLs and waste crawl budget

Faceted navigation handled: noindex or canonical on filter/sort combination pages

E-commerce faceted pages create thousands of near-duplicate URLs without proper handling

Canonical tags contain clean URLs (no tracking params like ?utm_source or ?fbclid)

Canonical with tracking parameters confuses Googlebot and propagates duplicate content signals