Responsive Checker – Mobile Simulator, Device Testing & Mockups

Frank Responsive Checker is a complete tool for testing site layouts and front-end performance directly inside your WordPress dashboard. By simulating 13+ specific device viewports, including the latest mobile screens, tablets, and desktop displays, this tool streamlines the debugging process for developers, designers, and website owners.

Whether you are performing a design audit, checking website accessibility, or testing custom breakpoints, this tool provides a native testing environment without requiring third-party subscriptions or external applications.

How this plugin works: Check Docs

Key Features List

• 13+ Device Presets: Test on modern smartphones, tablets, and desktop displays.
• Automatic Breakpoint Detection: Scan your CSS to find and jump to active media queries instantly.
• Visual Regression Testing: Save baseline layouts and use comparison sliders to catch pixel shifts.
• Side-by-Side Comparison: View multiple devices at once with fully synchronized scrolling.
• Accessibility Scanner: Audit WCAG color contrast, missing alt tags, and test keyboard focus maps.
• Advanced Developer Tools: Built-in DOM inspector, JavaScript console, and SEO analyzer.
• Network Throttling: Test performance and loading states with Slow 3G and Offline emulation.
• Touch Mode Simulation: Trigger authentic swipe and tap events for mobile interactions.
• Marketing Mockup Generator: Snap instant screenshots and create high-res transparent designs.
• Dark/Light Mode Toggles: Force color scheme preferences without changing OS settings.

Comprehensive Device Preview and Viewport Testing

Simulate how your web pages render on popular mobile screens, tablets, and desktop monitors instantly.

• Test layouts across modern smartphones like the iPhone 15 Pro, Samsung Galaxy S22, and Google Pixel.
• Review tablet views including iPad Pro and Galaxy Tab formats.
• Toggle between portrait and landscape orientation with a single click to verify responsive flow.
• Enter custom width and height values to test any specific viewport size not included in the presets.
• Save your custom device profiles to your personal library for quick access during future testing sessions.

Automatic CSS Breakpoint Detection

Never guess where your design breaks again. The built-in breakpoint scanner automatically reads your active stylesheet and extracts all media query breakpoints.

• Automatically detect and list all CSS breakpoints used on the current page.
• Click any detected breakpoint to instantly snap the viewport to that exact width.
• Review how your layout responds at critical structural transition points.

Visual Regression and Layout Comparison

Identify pixel-level changes and layout shifts using advanced visual comparison tools.

• Establish a baseline screenshot of your current layout to serve as a reference point.
• Use the visual comparison overlay slider to detect exact differences between your baseline and new code changes.
• Load multiple device frames side-by-side to examine layout consistency across different screen sizes.
• Synchronize scrolling across all active comparison panels to inspect lengthy pages effortlessly.

Web Accessibility Audits (WCAG Compliance)

Ensure your website is accessible to all users by running automated accessibility tests directly on your live pages.

• Perform WCAG contrast checks to verify that text remains readable against background colors.
• Scan the document for images missing alternative text attributes to improve screen reader compatibility.
• Visualize the keyboard navigation flow with numbered focus map badges.
• Simulate screen reader output to understand how visually impaired users experience your content.

Advanced Developer Tools and Debugging

Access a suite of advanced features designed specifically to help developers troubleshoot complex front-end issues.

• Network Throttling: Simulate Slow 3G or Offline network conditions to test page resilience and loading states.
• Touch Mode Emulation: Simulate true mobile touch events like swipes and taps while hiding the desktop cursor.
• Design Mode: Enable content editing directly within the viewport to test copy changes without modifying your database.
• SEO Analyzer: Scan page meta tags, heading structures, and essential SEO attributes instantly.
• Color Scheme Emulation: Force system dark or light mode preferences to test CSS media features.
• Dedicated Code Inspector: Open a built-in DOM inspector and JavaScript console specifically for the simulated viewport.

Instant Screenshots and Mockup Generator

Generate professional marketing assets and visual bug reports with one click.

• Capture high-fidelity PNG screenshots of the current viewport.
• Use the batch capture feature to automatically snap screenshots across multiple popular devices simultaneously.
• Export designs with transparent backgrounds or custom solid colors using the Mockup Generator.