Free tool
Mobile Website Checker for Your Device
The Mobile Website Checker reads the device you open it on and does not load a URL. It shows CSS viewport, visual viewport, pixel ratio, orientation, touch points, color scheme and connection where your browser provides them, then exports four manual checks, each starting as Not tested, as Markdown.
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Read this device, then record four manual checks
Open this page on the phone you want to check. It reads the screen and browser it is running in, shows the values below, and lets you record four checks that only a person can run: touch targets, forms with the keyboard open, rotation and an interrupted network. Every check starts as Not tested. Copy or download the result as Markdown without signing up.
You do not enter a URL, because this tool never loads one. To check a website on mobile, open that site on the phone yourself and follow the guide to checking and testing a website on mobile; use this page beside it to record which device you used.
This device, as the browser reports it
Readings update when you rotate the device, resize the window or change zoom. A value the browser does not provide shows as not available, never as zero.
Four checks only a person can run
The browser cannot tell whether a tap landed, a keyboard hid a button or a retry duplicated an order. Run each check on this device, then record what you saw. Every check starts as Not tested, and a status is your entry, not a verified result.
1. Touch targets
Tap the primary action and the controls next to it. Does each one respond once, with no mis-taps?
What you saw, in your own words. Up to 2,000 characters.
2. Forms with the keyboard open
Fill a form with the on-screen keyboard open. Can you still see the field, its error and the submit control?
What you saw, in your own words. Up to 2,000 characters.
3. Rotation
Rotate to landscape and back mid-task. Do the layout, your entered data and your place on the page survive?
What you saw, in your own words. Up to 2,000 characters.
4. Interrupted network
Interrupt the connection during a safe test action. Is the pending or failed state clear, and is it clear whether the action completed?
What you saw, in your own words. Up to 2,000 characters.
Copy or download the device record
Optional. The browser cannot reliably name your phone model, so add it yourself. Up to 200 characters.
Optional. Name the page or build you checked; this tool never opens it. Up to 200 characters.
The Markdown escapes pasted formatting and HTML. It includes your user agent string, which can identify your browser and device, so review it and your notes before sharing. This tool does not redact anything.
Read-only output. Select this text to copy it manually.
Collect reports on your own site with ContextCapture
ContextCapture adds a bug report widget to your website. Testers send a screenshot, their environment and their notes from the page, reports save to your inbox and, when the site’s destination is GitHub, open as issues in the repository you pick.
Use the same evidence habits on your own site: testers report from the live page, and each report saves to your inbox.
What each reading tells you
CSS viewport and visual viewport
The CSS viewport is the width and height, in CSS pixels, that your page layout works with. The visual viewport is the part currently visible, which can differ after pinch zoom or while the on-screen keyboard is open. MDN describes the visual viewport as separate from the layout viewport. Record the width at which a layout problem first appears.
Device pixel ratio and orientation
The device pixel ratio is how many physical pixels the screen uses for one CSS pixel. It explains why a sharp-looking image on one phone is blurry on another. Orientation shows portrait or landscape, so a rotation bug report names the state it started in.
Touch points and color scheme
Touch points is the maximum number of simultaneous touches the device reports; a laptop with a touch screen and a phone can both report a value above zero, so it does not prove the device is a phone. The color scheme is the light or dark preference the browser reports, which matters when a page styles itself for dark mode.
Connection
Some browsers expose a network information estimate: an effective connection type, downlink, round-trip time and a data-saver flag. Not every browser provides it, so it can show as not available. It is the browser’s estimate, not a speed test, and not a substitute for interrupting the connection yourself.
What this tool does not do
- It does not load your site. There is no URL field, no iframe and no screenshot service, and the tool adds no script of its own that contacts another site. A URL checker analyzes a page from somewhere else; this page only reads the browser it is open in. Site analytics, which run on every page of this site, may record that the page was visited and the tool was used.
- It does not run the checks. It cannot see a tap, a keyboard or a lost connection. A Passed status is a person’s entry, not a verified result, and a check you skipped stays Not tested in the export.
- It does not emulate a device. Opened in a desktop browser, it reports that desktop browser, including when Chrome Device Mode simulates a phone. Chrome says Device Mode does not run your code on a mobile device, so name an emulated run as emulation.
- It does not identify your phone model. The browser reports a user agent string, which is included in the record as the browser sent it. Add the model, OS and browser version yourself in the field provided.
After a check fails, write it up with the reproduction steps guide, paste the record into the bug report generator, and plan other environments with the cross-browser test matrix. If the layout breaks at a particular width, the responsive design testing guide shows how to find the first clipping width.
Published October 21, 2026. Updated October 21, 2026. Method: an original worksheet that reads standard browser values on the device it is opened on and exports them with four manual statuses. Inputs and readings stay in the current tab: this tool sends none of them anywhere, saves none of them and places none in shared URLs. Site analytics may record that the page was visited and the tool was used.
Examples for your team
Builder example
Fictional builder example: a maintainer opens the checker on a test phone, records the portrait viewport, and leaves the unrun rotation check as Not tested.
Start your 14-day free trialAgency / QA example
Fictional agency / QA example: a tester pastes the device record into a client bug report after marking the keyboard check Failed with a note.
Start your 14-day free trial