ProperHeaderHow to change the User-Agent header in Chrome
Want to see what a site sends to iPhones, test bot detection, or reproduce a bug a user reported on another browser? Change the User-Agent header in a couple of clicks. This is free in ProperHeader.
Switch to a mobile User-Agent
- Click the ProperHeader icon.
- Under Quick start, click Mobile User-Agent. It sets an iPhone Safari User-Agent.
- Allow ProperHeader on the site when asked, then reload.
To use your own, add a request header with Set, name User-Agent, and paste any value.
What this does and doesn't change
- Changes: the
User-AgentHTTP header sent to servers, which is what most server-side detection, redirects and logs use. - Doesn't change:
navigator.userAgentand Client Hints seen by JavaScript on the page, or the screen size. Scripts that check those still see your real browser.
For a full mobile emulation, with screen size, touch and the JavaScript user agent, also use Chrome DevTools' device toolbar (Ctrl+Shift+M). Use ProperHeader when you need the header changed on every request, across tabs, without DevTools open.
Keep it as a profile
Put the User-Agent in its own profile, for example "Mobile user agent", and switch to it from the toolbar when you need it. Pro allows unlimited profiles.
Questions
Does changing the User-Agent header change navigator.userAgent?
No. A header rule changes what servers receive. Page JavaScript still sees your real browser via navigator.userAgent and Client Hints. Use DevTools device emulation for that.
Is changing the User-Agent free?
Yes. It's a request header, and unlimited request headers are on ProperHeader's free plan.