User-Agent Checker
Decode what your user-agent string and Client Hints reveal — and catch spoofing with automatic consistency checks. Free, no signup.
How it works
1. Collect every signal
The page reads navigator.userAgent, navigator.platform and the full Client Hints set, while the server captures the real HTTP headers you sent.
2. Decode and cross-check
The user-agent is parsed into browser, engine, OS and device — then every pair of signals is compared for contradictions.
3. See what sites see
The report shows exactly what a website's script can read from your browser right now.
Frequently asked questions
What is a user-agent string?
The user-agent is a header every browser sends with each request. It names your browser engine and version, your operating system and your device type — one long string that sites use for compatibility, fingerprinting and bot detection.
What are Client Hints?
Client Hints (sec-ch-ua headers and navigator.userAgentData) are Chromium's structured replacement for the legacy user-agent string. They report the browser brand, platform and device details in clean fields — and can reveal more detail than the reduced user-agent does.
What does the consistency check do?
It cross-checks every signal your browser sends about itself: the HTTP user-agent against the JavaScript one, the declared operating system against Client Hints and navigator.platform, and the mobile flag against the device type. Mismatches are the classic fingerprint of a spoofed or tampered user-agent.
Why would my user-agent be spoofed?
Anti-detect browsers, automation tools and some extensions rewrite the user-agent to hide the real browser or OS. If you rely on a spoofed profile, this page shows you exactly what a website's script would see — and whether it contradicts itself.
Do you store my user-agent?
Reports are kept for 30 days so share links work. No raw IP is stored — reports are keyed by a salted hash — and the report contains only what your browser already sends to every site you visit.