🕵️ User-Agent Analysis Tool

Parses User-Agent strings to display browser, OS, device type, rendering engine, and bot determination.

Current Browser Information

Usage and Application Examples

  • Analyze User-Agent in access logs to determine browser and OS percentages
  • Determine bot (crawler) access and use for traffic analysis
  • For reference information when testing site display with a specific User-Agent
  • Simultaneous comparison and analysis of multiple UAs in batch analysis mode

What is User-Agent Parser?

The User-Agent Parser is a free online tool that decodes User-Agent strings and reveals detailed information about the browser, operating system, device type, rendering engine, and whether the request came from a bot or crawler. Web developers and analysts use this tool to understand how visitors access websites, diagnose browser compatibility issues, and identify automated traffic. Simply paste any User-Agent string and get instant technical breakdown.

How to Use

Locate the User-Agent string you want to analyze (found in browser developer tools, web server logs, or HTTP headers). Paste the complete User-Agent string into the tool's input field. Within seconds, the parser displays the browser name and version, operating system with version number, device type (desktop/mobile/tablet), rendering engine (Webkit, Gecko, etc.), and a bot classification if applicable. The results are immediately useful for debugging compatibility issues or understanding traffic patterns.

Use Cases

• Browser compatibility testing: Identify which browser version a user has when reporting bugs, enabling targeted troubleshooting.
• Server log analysis: Parse User-Agent strings from web server logs to categorize traffic by device and browser type.
• Bot detection: Determine whether a specific User-Agent belongs to a search engine crawler, social media bot, or legitimate browser.
• Mobile analytics: Quickly check device OS versions (iOS, Android versions) for users experiencing performance issues.

Tips & Insights

User-Agent strings can be spoofed or outdated, so they're not 100% reliable for critical security decisions. Modern browsers share similar Webkit engines, making differentiation harder than in the past. Headless browsers (like Puppeteer) and API clients often have distinctive User-Agent patterns. Web developers typically parse User-Agent strings server-side for analytics, but client-side detection is useful for JavaScript feature capability testing.

Frequently Asked Questions

What is User-Agent?

A User-Agent is an identification string that a browser or application sends to a Web server. It includes browser type, version, OS information, etc., and is used by the server for content optimization and access analysis.

Are the analysis results accurate?

This tool performs analysis using regular expression-based pattern matching. Major browsers (Chrome, Firefox, Safari, Edge, Opera) and operating systems (Windows, macOS, Linux, Android, iOS) can be determined with high accuracy. However, there may be cases where special custom User-Agents or newer browsers cannot be determined accurately.

How is the Bot decision made?

Keywords from major search engine crawlers such as Googlebot, Bingbot, Slurp (Yahoo), DuckDuckBot, Baiduspider, and YandexBot are detected from the User-Agent string. is displayed when a bot is detected.

How do I use the batch analysis mode?

Switch to the "Batch Analysis" tab, enter one User-Agent string per line in the text area, and press the "Batch Analysis" button to analyze all UAs at once and display the results in a comparison table format. This is useful for analyzing access logs.

Where do you get your current browser information from?

Browser information such as screen size, device pixel ratio, and language settings are obtained from the JavaScript navigator and window objects. All of this information is processed within the browser and is not sent to any external server.

How secure is the data?

This tool performs all processing in the browser (client-side). Neither the entered User-Agent string nor the analysis results are sent to the server. You can use this tool with peace of mind.

What do the different rendering engines mean, and why are they important?

Rendering engines are the core software components that interpret HTML/CSS and display web pages—common ones include Blink (Chrome), WebKit (Safari), and Gecko (Firefox). Understanding the rendering engine helps developers ensure websites display correctly across browsers, as each engine may handle CSS and JavaScript slightly differently. Knowing a user's rendering engine is more reliable than guessing browser compatibility based on browser name alone.

Can I save or export the analysis results for later reference?

Most User-Agent parsers allow you to copy the results or export them as text—check if your tool offers a "Copy Results" or "Export" button. You can also manually save the parsed information by taking a screenshot or copying the entire results section into a document. This is especially useful when analyzing User-Agent strings from web server logs for debugging or analytics.

What User-Agents cannot be correctly identified by the parser?

Heavily spoofed or modified User-Agents (where users or extensions deliberately alter the string) may produce inaccurate results, as the parser relies on standard formatting conventions. Very old User-Agents from discontinued browsers or devices may also not be recognized if they predate the parser's data. Custom or proprietary User-Agents from internal applications are typically not identifiable unless they follow standard naming patterns.

How should developers use User-Agent data for web development and testing?

Use User-Agent analysis to identify which browsers and devices your visitors use, then prioritize testing and optimization for those platforms. However, don't rely solely on User-Agent sniffing for feature detection—use feature detection libraries like Modernizr to check for specific capabilities instead. Analyze your User-Agent logs alongside Google Analytics data to understand your user base and make informed decisions about browser support.

What's the difference between browser version and rendering engine version?

Browser version refers to the release number of the entire browser application (e.g., Chrome 120.0), while rendering engine version is the internal version of the engine that powers it. Different browser versions may use the same or different rendering engine versions—for example, all Chromium-based browsers use the Blink engine but have different browser versions. For web compatibility, the rendering engine version is often more important than the browser version.

How can I analyze multiple User-Agents efficiently without parsing them one at a time?

Most parsers offer a batch mode where you can paste multiple User-Agent strings (one per line) to analyze them all at once. This is invaluable for web server administrators who want to analyze logs containing hundreds of User-Agents. Batch analysis shows you aggregate statistics about your visitors' browsers, operating systems, and devices in a single report.