Headers & UA

Headers & UA is a free web & network tool that runs entirely in your browser — your browser + header reference. No upload, no account, no limits.

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How to use Headers & UA

Open the Headers & UA tool.
Paste or type your URL, header or IP address into the input field.
The output updates as you type — adjust the options if you need a different format.
Copy the result, or share the URL to hand the exact input to someone else.

About Headers & UA

See what your browser reveals about itself right now — user agent, platform, languages, screen and viewport size, CPU cores, connection type and more — and browse a searchable reference of common HTTP request and response headers with plain-English descriptions.

What people use it for

Check your own user-agent string and browser capabilities.
Look up what a specific HTTP header does.
Confirm your viewport, screen size or device pixel ratio.

Frequently asked questions

What browser details are shown?

User agent, platform, languages, cookies, online status, CPU cores, screen and viewport, connection type and Do Not Track.

Is there a header reference?

Yes — a searchable list of common HTTP headers with short explanations.

Is it private?

Every calculation happens on this page, in your own browser. Your input is never sent to a server, never logged and never used for training — which also means the tool keeps working when you are offline.