ユーザーエージェント解析
ユーザーエージェント文字列を貼り付けるか、ご自身のものから始めてください。解析はブラウザー内で行われ、貼り付けた内容はどこにも送信されません。
ユーザーエージェント文字列はクライアントが送ると決めた内容にすぎません。簡単に変更でき、意図的にあいまいなことも多いため、結果は事実ではなく自己申告として扱ってください。
このテキストはまだ日本語で提供されていません。翻訳が公開されるまで英語で表示しています。
Every request a browser makes carries a User-Agent header: a line of text that names the browser, its rendering engine and the operating system it runs on. Websites use it to serve compatible code and to count visitors by platform; this site shows yours on the homepage.
The string is a historical patchwork. Almost every browser still begins with Mozilla/5.0, Chrome claims to be Safari, and Edge claims to be Chrome. The parser reads past that and reports the browser, engine, operating system, device type and CPU architecture the string claims.
Since 2022, Chromium-based browsers send a reduced user-agent: the operating system version and device model are frozen to fixed values, and the real details are only available as User-Agent Client Hints, which a page has to ask for. Where your browser offers them, they are shown next to the parsed result. Everything runs in your browser.
よくある質問
Can a website identify me from my user-agent?
Not on its own: millions of people share the same string. Combined with many other browser details it contributes to fingerprinting, which is why browsers now reduce it.
Why does my Windows 11 PC show Windows 10?
Reduced user-agent strings report "Windows NT 10.0" for both. The platform-version client hint tells them apart; it is shown when your browser supports it.
Is a bot always honest about being a bot?
No. Well-behaved crawlers such as Googlebot identify themselves, but anyone can send any user-agent. Verify crawlers by reverse DNS, not by the string.