ViewGrid — Responsive Viewer

Test phone, tablet and desktop layouts side by side in one tab. ViewGrid is a free, open-source Chromium and Firefox extension that helps you compare breakpoints without continually resizing your browser. The interface and reports support English, Turkish and Norwegian Bokmål. Responsive testing - 21 device profiles, 5 preset sets, custom sizes and up to 16 viewports. - Grid, row, column or free layouts; rotation, zoom, alignment and focus mode. - Scroll, click, navigation, reload and optional input/form/key synchronization, with independent channel controls. Comparison and reporting - Split, curtain and side-by-side comparisons; overlays for exported PNG/SVG designs. - PNG screenshots for one or all expanded viewports, with tiled large captures and a 32-megapixel limit. - Grouped findings for overflow, clipped text and small targets, with device measurements, filters and element highlighting. Markdown copy, JSON and printable HTML reports. Local analysis - Mobile, desktop or both by default: loading observations, DOM-based SEO, axe accessibility checks and experimental GEO signals. - Each analysis section copies or downloads its own Markdown report. Coverage, failed and uncertain checks remain visible; results become stale when the target changes. - No external analysis API, Google/CrUX request, account or additional engine installation is required. Privacy and limits No telemetry or cloud proxy. Settings stay in local browser storage; previewed sites make their usual network requests. Local observations are not Lighthouse scores or real-user Core Web Vitals data. Findings need human review; there is no compliance certification, whole-site crawl or DAST. GEO does not guarantee search ranking or AI visibility. Profiles provide CSS dimensions, without emulating mobile hardware or browser engines. Design overlays are not a Figma API integration. Screenshots capture viewports, not an entire long page document. Login, third-party cookies and sandbox restrictions can block some previews. Input/form/key synchronization is restricted to the same origin. Capture and replay are blocked for password, one-time-code and payment fields recognized by type, autocomplete and name/ID guards. Preview binding checks the actual parent workspace, direct iframe identity and verified frame/document registration; page-created messages are not accepted as binding evidence. Framing exceptions require verified workspace tabs. Firefox removes XFO and CSP frame-ancestors on direct previews; Chromium removes XFO and all CSP response headers on workspace subframes, including nested frames. Normal tabs retain their framing protections. Removing selected-site service-worker registrations may also affect normal tabs for that site; removal of cookies or site storage is not requested.