Most SEO tools share one uncomfortable habit: they send your content to someone else's servers. For organisations in the public sector, healthcare, or education, that's not a minor inconvenience — it's a real problem. We took a different route. The interaktiv SEO-Check Lite is a Plone 6 / Volto add-on that runs entirely in the editor's browser. No AI, no external service, no API calls to third parties. Nothing leaves the page. It lives as a floating badge right inside the editorial workflow, on the page your team is already editing. One tool covers two jobs that are usually split apart: core on-page SEO metrics (meta description, titles, internal links, a pixel-accurate Google snippet preview) and concrete WCAG accessibility checks (alt texts, link texts, table headers, heading hierarchy). Every check is deterministic and produces a transparent, CI-style score — no black box, no model to second-guess. Everything is configurable without code, and the add-on is a project-independent drop-in for Volto sites.