# phone Check > Phone width. No built page scrolls sideways on a 375px phone. Every page is opened in Chromium at 375 by 812 CSS pixels (the narrowest phone still sold in numbers) and fails when the document is wider than the viewport. The finding names the elements that stick out, widest first, so the fix lands on the cause. An `overflow-x. Hidden` on the page only hides it. Origin (the reference install, 12 October 2026). Canonical: https://heddle.pro/checks/phone --- With Heddle on your site it runs on every build, so a page that fails it is fixed before a buyer or a search engine sees it. ## Why it exists Phone width. No built page scrolls sideways on a 375px phone. Every page is opened in Chromium at 375 by 812 CSS pixels (the narrowest phone still sold in numbers) and fails when the document is wider than the viewport. The finding names the elements that stick out, widest first, so the fix lands on the cause. An overflow-x. Hidden on the page only hides it. Origin (the reference install, 12 October 2026). A re-audit at 375px found all 26 answer pages 388 to 534px wide and four of the eight blog posts 771 to 947px, the posts being the pages leads arrive on. Four causes, none of which the markup alone shows. An inline diagram 676px wide, bare source URLs used as link text (one 907px), a decorative band 431px wide, and the header's last nav link pushed off-screen. Every one was invisible on a desktop and every other check passed, because only a browser lays a page out. A page that scrolls sideways reads as broken on the device most searchers use, and Google indexes the mobile version of a page. Without Chromium it says so as a warning. An unmeasured page is reported as unmeasured. It is never counted as a pass. site.json phone.exempt ({ route. Reason }) spares a page only with a written reason. A header link laid out past the screen's edge (a nav strip that scrolls) is a warning. It does not widen the page, but a reader on a phone never sees it. From lib/checks/phone.mjs in the Heddle repository at 01a7655. ## Questions ### What does the phone check look for? No built page scrolls sideways on a 375px phone; the elements that stick out are named. ### How do I run it? Build the site, then run node bin/heddle.mjs check --only phone from the Heddle repository. Work with us ## Let the agents bring you the leads. Tell us about your business and who buys from you. On a short call we'll show you the searches your buyers make where you don't show up yet, and what the agents would do about them in their first month. On the call, for your site - The searches your buyers make Measured, with how many people make each one - Where you show up, and where you don't On Google and in ChatGPT's answers - The agents' first month The pages, fixes and links they would start with