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WEBSITE & SEO · BROWSER & CRAWLER IDENTITY INSPECTOR

User-Agent Checker, Parser & Crawler UA Directory

Instantly check your browser’s live User-Agent and Sec-CH-UA Client Hints (including real Windows 11 detection), or paste any User-Agent string or Nginx access log to decode browser engine, OS, device architecture, in-app WebViews, and 40+ search & AI crawler identities.

◈ 100% In-Browser · Live Client Hints & Bot Verification
Current Browser UAStandard Browser
Try a sample UA:

Mozilla/5.0

Browser / Client

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Rendering Engine / JS

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Operating System / Platform

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Device Type / Model

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CPU Architecture / Bitness

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Crawler / Bot Detection

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Visual Token-by-Token Anatomy (Click any pill to jump to explanation)

Why does a single User-Agent contain Mozilla/5.0, AppleWebKit, KHTML, Chrome, and Safari all at once? Here is what each segment actually means:

Token SegmentRole in UATechnical Meaning & Historical Context

Live User-Agent Client Hints (Sec-CH-UA) & Hardware Signals

Modern Chromium browsers freeze OS minor versions and device models inside the legacy UA string (e.g., Windows 11 still reports Windows NT 10.0). High-entropy Client Hints reveal the real values:

Environment Consistency & Anti-Spoofing Audit (6 Checks)

Cross-checks the claims in the UA string against live JS runtime globals (navigator.platform, window.chrome, maxTouchPoints, WebDriver) to detect UA switchers or DevTools emulation:

Consistent Browser Environment

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    How to use the User-Agent Checker & Parser

    1. Open the page to automatically detect your current browser’s User-Agent, rendering engine, OS, and live Sec-CH-UA Client Hints.
    2. Paste any custom User-Agent string into the top box—or pick from 41 verified search crawlers, AI bots, and browsers in the Directory tab—to inspect its token-by-token anatomy.
    3. Switch to the Batch Analyzer tab to parse up to 200 raw Nginx/Apache log lines at once, or use the Code Snippets tab to copy ready-to-run cURL, Python, fetch, and robots.txt rules.

    Official Search Engine, AI Bot & Social Crawler User-Agent Reference

    Below is the quick-reference matrix of the most important web crawlers, AI bots, and social link preview agents, including their robots.txt tokens and server-side verification methods:

    Major Search Engine, AI & Social Crawler User-Agent Reference
    Crawler / BotOperatorrobots.txt TokenPrimary Purpose & SEO AdviceIP / rDNS Verification
    Googlebot (Smartphone)GoogleGooglebotSearch Indexing (Mobile-First)*.googlebot.com / googlebot.json
    Googlebot (Desktop)GoogleGooglebotSearch Indexing (Desktop)*.googlebot.com / googlebot.json
    Google-InspectionToolGoogleGoogle-InspectionToolSearch Console Live URL Test*.googlebot.com / *.google.com
    Google-ExtendedGoogleGoogle-ExtendedGemini AI Training Control (No Search impact)robots.txt control token
    BingbotMicrosoftbingbotBing Search & Copilot Grounding*.search.msn.com / bingbot.json
    BaiduspiderBaiduBaiduspiderBaidu Search (PC & Mobile)*.baidu.com / *.baidu.jp
    ApplebotAppleApplebotSiri & Spotlight Search*.applebot.apple.com (17.0.0.0/8)
    GPTBotOpenAIGPTBotLLM Model Trainingopenai.com/gptbot.json
    OAI-SearchBotOpenAIOAI-SearchBotChatGPT Search Citations (Recommend Allow)openai.com/searchbot.json
    ChatGPT-UserOpenAIChatGPT-UserUser-Triggered Page Visit in ChatGPTopenai.com/chatgpt-user.json
    ClaudeBotAnthropicClaudeBotClaude AI Training & GroundingRespects robots.txt ClaudeBot
    PerplexityBotPerplexity AIPerplexityBotPerplexity AI Search Index (Recommend Allow)perplexity.ai/perplexitybot.json
    BytespiderByteDanceBytespiderDoubao / ByteDance LLM TrainingRespects robots.txt Bytespider
    CCBotCommon CrawlCCBotOpen Web Archive DatasetRespects robots.txt CCBot
    facebookexternalhitMetafacebookexternalhitFacebook / Instagram / Messenger Link PreviewMeta AS32934 IP ranges
    TwitterbotX Corp.TwitterbotX (Twitter) Card Link PreviewRespects robots.txt Twitterbot
    LinkedInBotLinkedInLinkedInBotLinkedIn Post Link PreviewLinkedIn crawler network
    AhrefsBot / SemrushBotAhrefs / SemrushAhrefsBot / SemrushBotBacklink Index & SEO Site Auditcrawler-ips API / *.semrush.com

    Frequently asked questions (Browser UA & Crawler UAs)

    What is my User-Agent and how does this User-Agent checker work?

    A User-Agent (UA) is a text string automatically sent in the HTTP User-Agent request header by your web browser, mobile app, or web crawler whenever it requests a webpage. It tells the server which browser, rendering engine, operating system, and device type you are using—or whether the visitor is an automated bot. As soon as you open this page, the tool reads your browser’s live navigator.userAgent and high-entropy User-Agent Client Hints locally in your browser.

    What are the official User-Agent strings for Googlebot (Smartphone, Desktop, InspectionTool, and Google-Extended)?

    (1) Googlebot Smartphone (primary for mobile-first indexing): Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/W.X.Y.Z Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html) where W.X.Y.Z updates with evergreen Chromium; (2) Googlebot Desktop: Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html); (3) Search Console live testing uses Google-InspectionTool/1.0; (4) Google-Extended is a robots.txt control token (not a separate crawler binary) that lets publishers opt out of Gemini AI training without affecting Google Search indexing.

    What are the User-Agent strings for AI crawlers like GPTBot, OAI-SearchBot, ChatGPT-User, ClaudeBot, PerplexityBot, and Bytespider?

    Major AI providers separate training crawlers from AI search citation crawlers: (1) GPTBot (OpenAI model training): Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; GPTBot/1.2; +https://openai.com/gptbot; (2) OAI-SearchBot (ChatGPT Search results, not used for training): Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko); compatible; OAI-SearchBot/1.0; +https://openai.com/searchbot; (3) ChatGPT-User (live user browsing requests); (4) ClaudeBot (Anthropic): includes ClaudeBot/1.0; +claudebot@anthropic.com; (5) PerplexityBot: includes PerplexityBot/1.0; (6) Bytespider (ByteDance). If you want AI search traffic without donating training data, allow OAI-SearchBot and PerplexityBot while disallowing GPTBot and CCBot in robots.txt.

    What are the official User-Agent strings for Bingbot, Applebot, Baiduspider, and YandexBot?

    (1) Microsoft Bingbot: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm) Chrome/W.X.Y.Z Safari/537.36; (2) Applebot (Siri & Spotlight): Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Safari/605.1.15 (Applebot/0.1; +http://www.apple.com/go/applebot); (3) Baiduspider: Mozilla/5.0 (compatible; Baiduspider-render/2.0; +http://www.baidu.com/search/spider.html); (4) YandexBot: Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bots). You can copy or inspect all 41 official strings in the Directory tab above.

    Why does almost every browser User-Agent start with Mozilla/5.0 and end with Safari/537.36?

    This is legacy compatibility baggage from the 1990s and 2000s. Early web servers checked for "Mozilla" before serving framesets, and later mobile sites checked for "AppleWebKit" and "Safari" before serving modern mobile stylesheets. To avoid being served broken fallback pages, Chrome (Blink) and Edge (Blink) kept Mozilla/5.0, AppleWebKit/537.36 (KHTML, like Gecko), Chrome/..., and Safari/537.36 in their strings. A reliable parser checks specific tokens (Edg/, OPR/, Chrome/) before falling back to Safari.

    Why does Windows 11 still show Windows NT 10.0 in the User-Agent string, and how do I detect Windows 11?

    To prevent legacy websites from breaking and to reduce passive fingerprinting, browsers froze the Windows kernel token in the User-Agent string at Windows NT 10.0 for both Windows 10 and Windows 11. The only reliable browser-side way to distinguish Windows 11 from Windows 10 is via User-Agent Client Hints: navigator.userAgentData.getHighEntropyValues(["platformVersion"]). A platformVersion major number of 13 or higher (e.g. 15.0.0) indicates Windows 11, whereas 1–10 indicates Windows 10.

    Why does Android Chrome show "Linux; Android 10; K" instead of my real phone model?

    Under Google Chrome’s User-Agent Reduction policy (rolled out since Chrome 110+), mobile Chrome freezes the OS version at Android 10 and replaces the hardware model with the single letter "K" in the default User-Agent header. Similarly, desktop macOS freezes at Intel Mac OS X 10_15_7. Servers that legitimately need the real device model must request the Sec-CH-UA-Model and Sec-CH-UA-Platform-Version headers via Accept-CH.

    How do I verify if a Googlebot, Bingbot, or GPTBot request in my server logs is genuine or spoofed?

    Never trust the User-Agent header alone for security or firewall whitelisting—any scraper can run curl -A "Googlebot". Verify crawlers using two methods: (1) Forward-confirmed reverse DNS (FCrDNS): run host <IP> to verify the PTR record ends in .googlebot.com, .google.com, .search.msn.com, or .baidu.com, then forward-resolve that hostname back to confirm it matches the original IP; or (2) Match the source IP against the operator’s official CIDR JSON file (googlebot.json, bingbot.json, openai.com/gptbot.json, openai.com/searchbot.json).

    What are the User-Agent strings for social link preview bots (Facebook, X/Twitter, LinkedIn, WhatsApp, Telegram, Slack)?

    When a URL is shared in a social post or chat message, the platform’s preview bot fetches Open Graph (og:title, og:image) tags using: (1) Facebook / Instagram / Messenger: facebookexternalhit/1.1; (2) X / Twitter: Twitterbot/1.0; (3) LinkedIn: LinkedInBot/1.0; (4) WhatsApp: WhatsApp/2.x; (5) Telegram: TelegramBot (like TwitterBot); (6) Slack: Slackbot-LinkExpanding 1.0. Make sure your CDN/WAF does not block these User-Agents, or shared links will appear without preview cards.

    How do I detect WeChat (MicroMessenger), Alipay, TikTok, or Instagram In-App WebViews from a User-Agent?

    Super-apps append custom container tokens to the system WebView User-Agent string: WeChat appends MicroMessenger/x.x (WeCom appends wxwork/); Alipay appends AlipayClient/ and NebulaSDK; TikTok / Douyin appends BytedanceWebview, musical_ly, or aweme; Instagram appends Instagram; Facebook In-App appends FBAN/ or FBAV/. Our parser highlights these in-app containers automatically.

    How does the Environment Consistency & Anti-Spoofing Audit detect User-Agent switchers?

    Simple browser UA switcher extensions only overwrite navigator.userAgent and the HTTP header while leaving underlying browser globals untouched. Our 6-point audit cross-checks the UA string’s claimed OS, engine, and touch support against navigator.platform, window.chrome / InstallTrigger, navigator.maxTouchPoints, Sec-CH-UA brands, and navigator.webdriver. For example, if a UA claims iPhone Mobile Safari on a desktop Chrome browser with maxTouchPoints=0 and window.chrome present, the mismatch is flagged immediately.

    Are my User-Agent strings or pasted access logs uploaded to any server?

    No. All User-Agent parsing, token breakdown, Client Hints inspection, anti-spoofing checks, and batch Nginx/Apache log analysis run 100% locally inside your web browser using JavaScript. No UA strings or log lines are transmitted to our servers.

    user agent checker and crawler UA practical guide and common questions

    What does a User-Agent checker and parser do?

    A User-Agent parser decodes the HTTP User-Agent string to identify the visitor’s browser brand, layout engine, operating system, CPU architecture, in-app WebView container, or automated crawler identity (such as Googlebot, Bingbot, GPTBot, or ClaudeBot).

    Who is this for, and when is it useful?

    Developers, technical SEO specialists, and site administrators debugging mobile/WebView rendering issues, auditing server access logs for AI/search crawlers, or writing robots.txt and WAF rules.

    Why check User-Agent Client Hints (Sec-CH-UA) in addition to the UA string?

    Modern Chromium browsers apply User-Agent Reduction, freezing Windows 10/11 at Windows NT 10.0, macOS at 10_15_7, and Android models at "K". High-entropy Client Hints reveal the real OS version, CPU architecture, and mobile model.

    Does a Googlebot or GPTBot User-Agent guarantee the request is from the real bot?

    No. Any HTTP client can spoof the User-Agent header. Always combine UA inspection with reverse DNS (PTR) lookups or official CIDR IP lists before trusting crawler traffic.

    Where is the work performed, and which services receive data?

    All parsing, Client Hints inspection, and batch log analysis run locally in your browser. No User-Agent strings or logs are uploaded.