Why it matters
Google generally tries to index iframe content as part of the embedding page, but that is not guaranteed because both are normal pages of their own. Google flattens shadow DOM and light DOM when it renders web components, and content that does not appear in the rendered HTML cannot be indexed.
How to meet it
Put the main content in the page's own DOM and use iframes for third-party widgets you do not need indexed. For web components and micro-frontend libraries that patch browser APIs, verify the result in Google's tools rather than trusting a library's promise of indexability.
How to test it
The rendered HTML in URL Inspection or the Rich Results Test shows the component's and embedded content's text as part of the page.
How Regensbot covers it
Decided automatically once Regensbot renders your pages.
Headless Chromium renders the page on an isolated render service, and the raw and the rendered HTML run through the same parsers.
Sources
Google documents04
- 01Understand the JavaScript SEO basicsGoogle Search Central (opens in a new tab)
- 02Fix Search-related JavaScript problemsGoogle Search Central (opens in a new tab)
- 03December 2023 Google SEO office hoursGoogle Search Central (SEO office hours transcript, December 2023) (opens in a new tab)
- 04New robots tag: indexifembeddedSearch Central blog (21 January 2022) (opens in a new tab)
Claims in the knowledge base04
- D2-C227SourceLightning session D: Rendering and JavaScriptGoogle's documentation
- D2-C235SourceLightning session D: Rendering and JavaScriptGoogle's documentation
- D2-C250n/aLightning session D: Rendering and JavaScriptThe author's interpretation
- D2-C240n/aLightning session D: Rendering and JavaScriptThe author's interpretation
Claim IDs refer to the Search Central Live 2026 knowledge base. The knowledge base (opens in a new tab)
- Source
- The claim is the cited document itself.
- n/a
- Nothing to verify: a quotation, framing, opinion or analysis.