Radial Viewport

Preview any site at desktop, tablet, and mobile widths — resize, screenshot full pages, drop guides, inspect elements.

Radial Viewport is a fast, no-friction responsive website viewport for designers and developers. Click the toolbar icon on any page and it opens in a resizable frame so you can see how it looks at every breakpoint — without resizing your whole browser window or opening DevTools. Because the page loads in a real frame with its own viewport, the site's actual responsive CSS (media queries) fires, so what you see is what your visitors get. Features • Desktop, Tablet (768px), and Mobile (390px) presets — keys 1 / 2 / 3 • Drag the edge to resize to any width; lock a fixed width (e.g. 1440) that scales to fill the pane so a full desktop layout stays visible on a laptop • Pages sidebar (P) — every page on the site, discovered from its links and sitemap, with search and grouped sections; the address bar doubles as page search • Visual sitemap (M) — the whole site as a zoomable map • Page metadata at a glance — title & description with SEO character counts, OG image, robots • Edit text (E) — click any text and retype it, live on the page; each change records an exact before → after • Comment (C) — pin notes on elements • Copy for AI — one click turns your comments and text edits into a single prompt for Claude Code, Codex, or any coding agent • Screenshots — current view or full page, always at 2×, saved to Downloads • Inspect mode (I) — hover any element for size, typography (weight, line-height, letter-spacing), and hex colors; click to copy • Rulers and screen-fixed guides — drag from a ruler to drop a guide • Back / forward / reload, with an address bar that tracks navigation inside the frame • Loads sites that normally block framing (header handling is scoped to the extension's own tabs, so your other tabs are unaffected) Private and local Radial Viewport runs entirely in your browser, with no account and no server of ours between you and the sites you preview. The only data it sends is anonymous feature-usage counts (event names like "a screenshot was taken" — never URLs, page content, or your notes), with an off switch in the panel. Full schema: https://radial.to/docs/viewport/usage-data · Privacy policy: https://radial.to/viewport-privacy From the team building Radial — a visual interface for designers to build and maintain marketing websites with Claude Code and Codex. https://radial.to