URL: /rules/core/doctype --- title: "Doctype" description: "Checks for valid HTML5 doctype declaration" --- Checks for valid HTML5 doctype declaration | | | |---|---| | **Rule ID** | `core/doctype` | | **Category** | [Core SEO](/rules/core) | | **Scope** | Per-page | | **Severity** | warning | | **Weight** | 5/10 | ## Solution Add `` at the very start of your HTML document, before the `` tag. This declaration tells browsers to render the page in standards mode rather than quirks mode, ensuring consistent rendering across browsers. Without a proper doctype, browsers may render the page inconsistently. ## Enable / Disable ### Disable this rule ```toml squirrel.toml [rules] disable = ["core/doctype"] ``` ### Disable all Core SEO rules ```toml squirrel.toml [rules] disable = ["core/*"] ``` ### Enable only this rule ```toml squirrel.toml [rules] enable = ["core/doctype"] disable = ["*"] ```