How to use AKCLNT Responsive Checker

Test your first site

1. Paste a URL into the box at the top of the home page — example.com is enough, AKCLNT Responsive Checker adds https:// for you.
2. Press Check now. Your site loads on three devices: iPhone 16, iPad Pro 11" and a 1440px desktop.
3. Scroll inside any frame to use the site normally — links, menus and forms all work.

The three modes

Single mode is the fastest way to find the exact width where a layout breaks: drag the slider slowly and watch for the moment text overlaps or a horizontal scrollbar appears. The breakpoint buttons (360, 390, 576, 768, 992, 1280, 1440) jump straight to common sizes.

Picking devices

The device dock above the preview holds all 56 presets.

• Type tabs — All, Phones, Tablets, Desktop, or ★ your favourites.
• Brand pills — narrow to Apple, Samsung, Google, Others, Tablets or Desktop. The number shows how many devices match.
• Tiles — click a tile to add or remove it. Hover a tile and click ★ to favourite it; favourites are remembered in your browser.
• Quick presets — Big 3 (phone, tablet, desktop), iPhones and Android.
• ＋ Custom size — add any width × height, from 240 to 3840 px wide.

Every device also has its own page with specs and a media query — browse them in device sizes.

Zoom, rotate and frames

• Zoom slider (20–100%) scales the frames so large devices fit. + / − on the keyboard work too.
• ⤢ Fit picks the zoom that fits all selected devices on your screen.
• Portrait / Landscape rotates every frame. Press R.
• 📱 Frame toggles the device bezels if you want a cleaner view.
• ⛶ Fullscreen (F) gives the preview the whole window. Esc exits.

Site checks and health score

Under the preview, AKCLNT Responsive Checker checks HTTPS, response time and whether the page can be embedded, and shows how many widths you tested. These feed a health score out of 100.

The visual issue checklist lets you record what you see: click an item once to mark it as passing, twice to mark it as an issue. Failed items link to their fix in Issues & Fixes and also count towards the score.

Reports, share links and QR

• 📋 Report copies a text report; ⬇ Download report saves it as a .txt file. Failed checklist items include the code to fix them — perfect for sending to a developer.
• 🔗 Share copies a link that reopens the exact same test: URL, devices, mode and orientation.
• ▣ QR shows a QR code of the URL so you can open it on a real phone in seconds.

Keyboard shortcuts

Bookmarklet and screen size

In the What's my screen size section you'll find your live viewport and a bookmarklet. Drag it to your bookmarks bar; on any website, click it to open that page in AKCLNT Responsive Checker instantly.