User agent checker

Use this user agent checker to inspect your browser or up to 50 pasted strings. Read browser, engine and OS tokens, frozen-version warnings and documented crawler matches.

A user agent is text that software sends to describe itself. This local checker reads browser, engine, operating system and device tokens, flags known crawlers, and warns about frozen values. Default Client Hints describe your browser separately from pasted strings. Copy or download the JSON report. Headers can be faked; use an IP check to help verify crawlers.

One string per line, up to 50. Input stays in your browser.

My browser's Client Hints

These values describe your current browser, even when the checker contains a pasted string. Client Hints are a separate browser API and cannot be recovered from a user agent string.

This browser does not expose navigator.userAgentData. Firefox and Safari commonly use the user agent string instead.

Only default brands, platform and mobile are read. Device model, full versions and other high entropy hints are not requested. A brand list can include a deliberately unusual brand; it does not name an installed browser.

Why the reported versions can be frozen

Browsers reduce user agent detail to limit tracking and keep old websites working. A fixed OS version or a browser version ending in .0.0.0 can be a compatibility value.

Use these results to interpret a header or troubleshoot a request. They do not identify a person, prove a device model or establish that a crawler is genuine. Confirm crawler identity with the request IP and operator guidance.

Chrome Client Hints documentation

Signatures this checker recognizes

66 signatures. Sources reviewed on 2026-10-11. Robots-only names are excluded.

The Meta and ByteDance signatures reuse our crawler directory; their documentation was unavailable during this review.

Show the signature directory
OAI-SearchBot
OpenAI. AI search: ChatGPT search. robots.txt token: OAI-SearchBot. Documentation
ChatGPT-User
OpenAI. User-triggered fetching: ChatGPT. robots.txt token: ChatGPT-User. Documentation
GPTBot
OpenAI. AI training: future OpenAI models. robots.txt token: GPTBot. Documentation
Claude-SearchBot
Anthropic. AI search: Claude search. robots.txt token: Claude-SearchBot. Documentation
Claude-User
Anthropic. User-triggered fetching: Claude. robots.txt token: Claude-User. Documentation
ClaudeBot
Anthropic. AI training: future Claude models. robots.txt token: ClaudeBot. Documentation
PerplexityBot
Perplexity. AI search: Perplexity. robots.txt token: PerplexityBot. Documentation
Perplexity-User
Perplexity. User-triggered fetching: Perplexity. robots.txt token: Perplexity-User. Documentation
Googlebot
Google. Search engine: Google Search and AI Overviews. robots.txt token: Googlebot. Documentation
Bingbot
Microsoft. Search engine: Bing and Copilot. robots.txt token: Bingbot. Documentation
Applebot
Apple. AI search: Siri and Spotlight. robots.txt token: Applebot. Documentation
DuckAssistBot
DuckDuckGo. AI search: DuckDuckGo answers. robots.txt token: DuckAssistBot. Documentation
MistralAI-User
Mistral. User-triggered fetching: Vibe. robots.txt token: MistralAI-User. Documentation
MistralAI-Index
Mistral. AI search: Vibe search. robots.txt token: MistralAI-Index. Documentation
MistralAI-Training
Mistral. AI training: future Mistral models. robots.txt token: MistralAI-Training. Documentation
Meta-WebIndexer
Meta. AI search: Meta AI search. robots.txt token: Meta-WebIndexer. Documentation
Meta-ExternalAgent
Meta. AI training: Meta AI. robots.txt token: Meta-ExternalAgent. Documentation
Meta-ExternalFetcher
Meta. User-triggered fetching: Meta AI. robots.txt token: Meta-ExternalFetcher. Documentation
Amazonbot
Amazon. AI training: Amazon products and models. robots.txt token: Amazonbot. Documentation
Amzn-SearchBot
Amazon. AI search: Alexa search. robots.txt token: Amzn-SearchBot. Documentation
Amzn-User
Amazon. User-triggered fetching: Alexa. robots.txt token: Amzn-User. Documentation
CCBot
Common Crawl. AI training: the open dataset most models train on. robots.txt token: CCBot. Documentation
Bytespider
ByteDance. AI training: Doubao. robots.txt token: Bytespider. Documentation
YouBot
You.com. AI search: You.com answers. robots.txt token: YouBot. Documentation
OAI-AdsBot
OpenAI. Monitoring: Advertising landing page checks. robots.txt token: OAI-AdsBot. Documentation
Googlebot-Image
Google. Search engine: Image indexing. robots.txt token: Googlebot-Image. Documentation
Googlebot-Video
Google. Search engine: Video indexing. robots.txt token: Googlebot-Video. Documentation
Storebot-Google
Google. Search engine: Shopping pages. robots.txt token: Storebot-Google. Documentation
Google-InspectionTool
Google. Search engine: Search Console inspection. robots.txt token: Google-InspectionTool. Documentation
GoogleOther
Google. Search engine: Public content fetching. robots.txt token: GoogleOther. Documentation
GoogleOther-Image
Google. Search engine: Image data research. robots.txt token: GoogleOther-Image. Documentation
GoogleOther-Video
Google. Search engine: Video data research. robots.txt token: GoogleOther-Video. Documentation
Google-CloudVertexBot
Google. User-triggered fetching: Vertex AI customer agents. robots.txt token: Google-CloudVertexBot. Documentation
APIs-Google
Google. Monitoring: Push notifications. robots.txt token: APIs-Google. Documentation
AdsBot-Google-Mobile
Google. Monitoring: Mobile advertising page quality. robots.txt token: AdsBot-Google-Mobile. Documentation
AdsBot-Google
Google. Monitoring: Advertising page quality. robots.txt token: AdsBot-Google. Documentation
Mediapartners-Google
Google. Monitoring: AdSense contextual ads. robots.txt token: Mediapartners-Google. Documentation
Google-Safety
Google. Monitoring: Malware and abuse checks. robots.txt token: No applicable control documented. Documentation
Google-CWS
Google. User-triggered fetching: Chrome Web Store supplied URLs. robots.txt token: No applicable control documented. Documentation
FeedFetcher-Google
Google. Search engine: Publisher feeds. robots.txt token: No applicable control documented. Documentation
Google-GeminiNotebook
Google. User-triggered fetching: Gemini Notebook supplied sources. robots.txt token: No applicable control documented. Documentation
Google-Agent
Google. User-triggered fetching: User-requested agent navigation. robots.txt token: No applicable control documented. Documentation
GoogleMessages
Google. Social previews and integrations: Messages link previews. robots.txt token: No applicable control documented. Documentation
Google-Pinpoint
Google. User-triggered fetching: Pinpoint supplied sources. robots.txt token: No applicable control documented. Documentation
GoogleProducer
Google. Search engine: Publisher Center feeds. robots.txt token: No applicable control documented. Documentation
Google-Read-Aloud
Google. User-triggered fetching: Reading pages aloud. robots.txt token: No applicable control documented. Documentation
Google-Site-Verification
Google. Monitoring: Site ownership verification. robots.txt token: No applicable control documented. Documentation
AhrefsBot
Ahrefs. SEO tool: Backlink indexing. robots.txt token: AhrefsBot. Documentation
AhrefsSiteAudit
Ahrefs. SEO tool: Site audits. robots.txt token: AhrefsSiteAudit. Documentation
SemrushBot
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot. Documentation
SiteAuditBot
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SiteAuditBot. Documentation
SemrushBot-BA
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot-BA. Documentation
SemrushBot-SI
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot-SI. Documentation
SemrushBot-SWA
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot-SWA. Documentation
SplitSignalBot
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SplitSignalBot. Documentation
SemrushBot-OCOB
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot-OCOB. Documentation
SemrushBot-FT
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot-FT. Documentation
RyteBot
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: RyteBot. Documentation
SemrushBot-ESI
Semrush. SEO tool: SEO analysis and site auditing. robots.txt token: SemrushBot-ESI. Documentation
MJ12bot
Majestic. SEO tool: Backlink mapping. robots.txt token: MJ12bot. Documentation
Pinterestbot
Pinterest. Social previews and integrations: Pins and link previews. robots.txt token: Pinterestbot. Documentation
Slackbot-LinkExpanding
Slack. Social previews and integrations: Shared links, media and integrations. robots.txt token: No applicable control documented. Documentation
Slack-ImgProxy
Slack. Social previews and integrations: Shared links, media and integrations. robots.txt token: No applicable control documented. Documentation
Slackbot
Slack. Social previews and integrations: Shared links, media and integrations. robots.txt token: No applicable control documented. Documentation
UptimeRobot
UptimeRobot. Monitoring: Availability monitoring. robots.txt token: No applicable control documented. Documentation
StatusCake
StatusCake. Monitoring: Website monitoring. robots.txt token: No applicable control documented. Documentation

How this tool works

Read your browser string
The page reads navigator.userAgent after it loads. Paste up to 50 strings, with a maximum of 8,192 UTF-16 units per string and 100,000 overall. Parsing and JSON export stay in your browser. Default Client Hints, where supported, describe your visitor browser and are labelled separately. No high entropy hints are requested.
Check the classification
A documented bot token takes priority over browser compatibility text. Results show its operator, purpose and robots.txt token. Browser results report claimed version tokens and warn about common frozen Chrome, Windows, Android and macOS values. The AppleWebKit token in Chromium is not a Blink version. Reduced headers and desktop-mode iPads can hide the actual device.
Verify before allowing access
Any client can claim to be a browser or crawler. Check its original request IP against published ranges and read the operator documentation. Robots-only controls such as Google-Extended and Applebot-Extended are not separate HTTP user agents.

Related tools

  • Crawler IP checker

    Use this crawler IP checker to compare up to 50 addresses with published bot ranges. Paste IPs or a log excerpt, then review the operator matches.

  • HTTP header checker

    Inspect every redirect with the HTTP header checker. Review security grades and cookie flags, then compare browser and crawler responses.

  • AI crawler check

    Use this AI crawler checker to review robots.txt rules, indexing signals and HTTP responses. Inspect blocked access before changing your site's rules.

Before you start

No. Client Hints come from a separate browser API or request headers. They cannot be reconstructed from pasted text. This page reads only your current browser's default brands, platform and mobile flag where available, and does not request model or full-version hints. The pasted-string JSON report contains only parsed text.

No. Many devices report identical strings, and browsers may deliberately reduce the details they expose. This tool does not fingerprint your browser or infer who you are.

Bots often include browser compatibility text. The checker matches specific documented bot tokens first. That text does not mean a human opened the page or that the crawler renders JavaScript.

Often it cannot. Windows 10 and Windows 11 can both report Windows NT 10.0. Brave can use the same user agent as Chrome. iPads in desktop mode can report macOS. The results describe what the string reveals.

Check what assistants can find

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