User Agent

Every time a browser makes a request, it introduces itself with a User-Agent header. The string encodes the browser family, version, rendering engine, operating system and, historically, legacy strings that survive for compatibility reasons (which is why even Safari still announces "Mozilla").

This page reads your browser's current User-Agent and parses it locally. Nothing is sent to our servers — the decoding happens in your browser.

What it tells the server

• Browser + version — choose the right CSS/JS polyfills.
• Operating system — choose the right download (macOS/Windows/Linux/iOS/Android).
• Device category — mobile vs tablet vs desktop.

FAQ

Can I change my User-Agent? Yes. Every browser has a developer-tools option to spoof the User-Agent. Extensions can also rewrite it per site.

Why do most User-Agents start with "Mozilla/5.0"? Historical compatibility — the 90s web filtered features based on that prefix, and browsers kept it forever to avoid breaking old sites.

Is my User-Agent unique? Often yes enough to contribute to browser fingerprinting. Combined with IP, timezone and a few other signals, it becomes a strong identifier.