Can I validate my whole site with this tool?

This form checks a pasted JSON snippet; it does not crawl your website. For a graph or array, the current implementation selects the first typed node rather than validating every entity. Isolate a node for a focused first pass, then inspect the complete page with an appropriate external validator. A whole-site audit also needs representative URLs, template ownership, store contexts and a review of visible values.

References: Schema.org Markup Validator; Google structured-data guidelines.