Every check traces to a primary source.
We don't grade on opinion. Every weight, threshold, and recommendation in the audit cites back to documentation published by Google, Microsoft, OpenAI, Anthropic, Perplexity, the W3C, or IETF. Here are the sources we use.
Primary sources for how Google, Bing, and AI search surfaces discover, render, and cite the web.
- Google Search Central - SEO Starter GuideGoogle
Baseline of Google's own SEO guidance. Reference for crawl, render, and indexing fundamentals.
https://developers.google.com/search/docs/fundamentals/seo-starter-guide - Google - About AI Overviews and AI ModeGoogle
Official documentation on how AI Overviews are generated and how creators can influence inclusion.
https://developers.google.com/search/docs/appearance/ai-features - Google Search Quality Rater GuidelinesGoogle
E-E-A-T definitions and rater rubric. The source-of-truth for what 'experience' and 'trust' mean to Google.
https://services.google.com/fh/files/misc/hsw-sqrg.pdf - Bing Webmaster GuidelinesMicrosoft
Bing's crawl and ranking guidance. Bing powers ChatGPT Search's index, so this matters for AI citation.
https://www.bing.com/webmasters/help/webmasters-guidelines-30fba23a
How AI assistants identify themselves, request content, and decide what to cite.
- OpenAI - Overview of OpenAI CrawlersOpenAI
OAI-SearchBot, ChatGPT-User, and GPTBot - identifiers, IP ranges, and opt-out behavior.
https://platform.openai.com/docs/bots - Anthropic - ClaudeBot crawlerAnthropic
Claude's crawler identifier, behavior, and robots.txt expectations.
https://docs.anthropic.com/en/docs/agents-and-tools/web-search-tool - Perplexity - PerplexityBot and Perplexity-UserPerplexity
Perplexity's two crawler identities and how each is used at index vs answer time.
https://docs.perplexity.ai/guides/bots - llms.txt proposalllmstxt.org
Proposed standard for a site-level file telling LLMs what's safe to read and cite. Adopted by major AI tools.
https://llmstxt.org/
Specs we validate against when scoring schema density and richness.
- Schema.org full vocabularySchema.org
Canonical vocabulary for structured data. Source-of-truth for every @type we accept.
https://schema.org/docs/full.html - Google - Structured data general guidelinesGoogle
Required vs recommended properties for rich-result eligibility. Drives the AIO and Foundational check weights.
https://developers.google.com/search/docs/appearance/structured-data/sd-policies - JSON-LD 1.1 specificationW3C
Wire format for the structured data we parse on every page.
https://www.w3.org/TR/json-ld11/
Specs for the performance signals that feed our Technical dimension.
- web.dev - Core Web VitalsGoogle / Chrome team
LCP, CLS, INP thresholds and measurement guidance. Our Technical dimension thresholds match.
https://web.dev/articles/vitals - PageSpeed Insights APIGoogle
Lab + field data source we query during every audit when reachable.
https://developers.google.com/speed/docs/insights/v5/get-started - Chrome UX Report (CrUX)Google
Field-data origin we cache to avoid re-querying PSI on every audit.
https://developer.chrome.com/docs/crux
How modern engines actually fetch and execute the page.
- robots.txt specification (RFC 9309)IETF
Standardised parsing rules. Our discovery layer respects this exactly.
https://www.rfc-editor.org/rfc/rfc9309.html - Google - JavaScript SEO basicsGoogle
Two-pass indexing model. Justifies our render-vs-HTML diff check.
https://developers.google.com/search/docs/crawling-indexing/javascript/javascript-seo-basics - Sitemaps XML formatsitemaps.org
Spec our sitemap generator and validator conform to.
https://www.sitemaps.org/protocol.html
See how each source maps to a check
The methodology page documents which references inform which check and dimension, with the weight chosen for each.