free tool
HTTP headers checker
See the request headers your browser sends to every website, and what a page can read about your device with JavaScript.
- free
- no account
- runs in your browser
A time zone or language that does not fit the IP's country is one of the first things sites compare to spot a proxy.
How it works
What every request carries.
Each time your browser asks for a page, an image or a script, it sends headers: the browser and system it runs on, the languages you prefer, what it accepts and where the request comes from.
A proxy changes the IP address a site sees, not these headers. Over HTTPS the proxy only passes encrypted traffic along, so it cannot read or change them.
Sites put the headers together with what JavaScript reads, like the time zone and screen size, to tell visitors apart. A profile that does not fit its IP stands out.
- User-Agent and client hints name the browser, its version and the operating system.
- Accept-Language lists your languages: keep it in line with the proxy's country.
- The Sec-Fetch headers tell the site how the request was made.
- Headers our own network adds on the way, and cookies, are left out.
Questions
Lines of text your browser sends with every request, before any content. They tell the server who is asking and what it can handle: the browser, your languages, the formats it accepts and where the request comes from.
No. A proxy changes your IP address. Over HTTPS it cannot see or change the headers at all, so your User-Agent and languages reach the site exactly as your browser sends them.
The User-Agent header names your browser, its version and your operating system, such as Chrome on Windows. Sites use it to serve the right page and, together with other signals, to recognise devices.
Newer headers starting with Sec-CH-UA that carry the same facts as the user agent in a structured form. Chromium browsers send the basic ones with every request and more detailed ones when a site asks for them.
This page leaves out the headers our own network adds on the way, like Cloudflare's, and never shows cookies or authorization headers. Accept-Encoding is left out too, because Cloudflare rewrites it before the request reaches us.
Sites can compare your browser's time zone and languages with the location of your IP. A US address with a browser set to a European time zone stands out. Antidetect browsers set the time zone, language and location to match the proxy.
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