User Agent Parser
Parse any browser user agent string.
How to use User Agent Parser
Paste Your User Agent String
Click the text input field labeled 'Enter User Agent String' and paste your complete user agent string. You can copy this from your browser's developer tools (F12 > Network tab > Headers section) or use a sample string provided below the input box.
Click the Parse Button
Press the blue 'Parse User Agent' button located directly below the input field. The parser processes your string instantly in your browser without sending any data to external servers.
Review Your Results
View detailed results in the output panel showing Browser Name, Version, Operating System, Device Type, Device Brand, Engine, and Bot Status. Each field is clearly labeled with a blue header and corresponding value displayed below.
Copy or Download Results
Click the 'Copy Results' button to copy all parsed data to your clipboard, or select 'Download as JSON' to save the structured data as a .json file to your computer.
Related Tools
User agent parser online: identify any browser or device
User agent parser online: identify any browser or device
A user agent parser reads a user agent string and breaks it down into browser name and version, operating system, device type, and rendering engine, giving you a clear, human-readable breakdown in seconds. Use the free ToolHQ user agent parser to analyze your current browser's UA string or parse any string you paste in.
A user agent parser is a developer tool that decodes the User-Agent HTTP header string sent by browsers and bots to web servers, extracting structured information about the browser, OS, device type, and rendering engine from what is otherwise a dense, opaque text string.
User agent strings look like this: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36. Reading that manually tells experienced developers something, but parsing it accurately across hundreds of browser and device combinations requires pattern-matching logic. A parser handles that automatically.
Key takeaways
- Detects browser name, version, engine, operating system, and device type from any UA string
- Automatically reads your current browser's UA string so you see your own info immediately
- Paste any UA string to parse it: useful for server logs, testing, and bot detection
- Parsed entirely in your browser, no UA string is sent to a server
- Free, instant, no account required
What a user agent string is and how parsing works
The HTTP User-Agent header, defined in early HTTP standards and still in widespread use, is a string that browsers and other HTTP clients send to web servers with every request. It is intended to identify the software making the request so the server can respond appropriately.
As Wikipedia describes, the UA string format has evolved chaotically over decades. Because each browser wanted to be recognized by websites that checked for specific browsers, most modern browsers include tokens from multiple browsers in their UA strings. Chrome includes "Safari" in its UA string. Firefox includes "Gecko." Internet Explorer included "Mozilla." The result is that UA strings are not human-readable at a glance.
A parser uses pattern-matching rules against a maintained database of known browser tokens, engine identifiers, OS patterns, and device identifiers to extract structured fields:
- Browser: name (Chrome, Firefox, Safari, Edge) and version number
- Engine: rendering engine (Blink, Gecko, WebKit, Trident)
- OS: operating system (Windows, macOS, iOS, Android, Linux) and version
- Device type: desktop, mobile, tablet, or bot
- Device model: for mobile devices, the specific model (iPhone 14, Samsung Galaxy S23) when identifiable
ToolHQ's user agent parser reads your current browser's UA string automatically when you open the tool, showing your own information immediately. You can also paste any UA string to parse it, which is useful when analyzing server logs, debugging device-specific issues, or testing how a specific client identifies itself.
When a user agent parser is useful
Debugging device-specific issues. A user reports your website behaves differently on their device. You want to reproduce the issue. They send you their UA string from the browser's developer tools. Paste it into the parser to immediately understand what browser version and OS they are running.
Analyzing web server access logs. Server logs contain one UA string per request. Developers analyzing traffic patterns or investigating unusual behavior paste UA strings from logs into the parser to identify which clients are making requests.
Bot and crawler identification. Search engine crawlers (Googlebot, Bingbot), AI crawlers (GPTBot, CCBot), and site monitoring tools all identify themselves in their UA strings. Parsing them confirms which crawler is responsible for unusual traffic patterns.
Testing browser compatibility. QA teams and developers sometimes need to verify that their browser testing setup is sending the correct UA string. Parsing the current UA confirms the test environment is what it should be.
Understanding your own browser setup. For non-developers, the UA parser answers a simple question: what exactly does "my browser" mean? The parsed output translates a technical string into the information a support team or developer would need.
Mini-story: Laura, a 33-year-old QA engineer in Melbourne, was troubleshooting a rendering issue reported by a client on an older Samsung tablet. The client sent her the UA string from the tablet's browser settings. She pasted it into the ToolHQ user agent parser and got immediate results: Android 11, Samsung Internet Browser 14.2, WebKit 537.36. That gave her the exact environment to reproduce in her testing setup. She confirmed the rendering bug, traced it to a CSS property with incomplete Samsung Browser support, and fixed it within the hour.
How to use the user agent parser: step by step
See your current browser info. When you open the tool, it automatically reads your browser's User-Agent header and displays the parsed breakdown. No input needed to check your own browser.
Paste a different UA string. To analyze a specific UA string from a log file, a reported issue, or a testing scenario, paste the raw UA string into the input field. The parser processes it immediately.
Review the parsed fields. The output shows: browser name and version, rendering engine, OS name and version, and device type (desktop, mobile, tablet, or bot). For mobile devices, the model may also be identified.
Use the results. Copy the relevant fields for a support ticket, debugging notes, or compatibility matrix. The parsed format is much clearer to communicate than the raw UA string.
Try different UA strings. You can paste multiple UA strings one at a time to compare different client environments.
Tips for working with user agent strings
Do not rely on UA strings alone for device detection. UA strings can be spoofed. Any browser can be configured to send a different UA string. For production applications that need to adapt to device capabilities, feature detection (checking whether a CSS feature or JavaScript API is available) is more reliable than UA-based detection.
Know the common bot UA patterns. Googlebot identifies itself as Googlebot/2.1. Bingbot uses bingbot/2.0. OpenAI's GPTBot uses GPTBot/1.0. Common Crawl uses CCBot. If you see unusual traffic in server logs, parsing the UA strings quickly identifies whether the traffic is from a known crawler or an unrecognized bot.
Use UA data for analytics and logging, not security. UA strings are useful for understanding your traffic breakdown by browser and device type. They are not reliable for security decisions since they are trivially spoofed.
Find your UA string in browser DevTools. In Chrome: open DevTools, go to Network, load any page, click a request, find the "User-Agent" header in Request Headers. You can also type navigator.userAgent in the Console tab. This is the fastest way to get your current UA string.
Mini-story: Ravi, a 40-year-old web developer in Singapore, was investigating a client site with unusually high server load. Pulling the access logs, he saw thousands of requests per hour from a UA string he did not recognize: a mix of "bot" and a version number that did not match any known crawler. He pasted the UA into the ToolHQ parser. The tool identified it as a commercial scraper tool, not a legitimate search crawler. He added a robots.txt rule to block that user agent using the robots.txt generator and the traffic dropped off within hours.
For network-level investigation alongside UA parsing, the DNS lookup tool lets you trace IP addresses associated with suspicious traffic, and the what-is-my-IP tool shows your current public IP alongside your UA information.
Frequently asked questions
What is a user agent string?
A user agent string is a text header that browsers and HTTP clients send to web servers with every request. It identifies the software making the request, including browser name, version, operating system, and device type.
Can I parse user agent strings from server logs?
Yes. Copy any user agent string from your server logs and paste it into the parser. The tool extracts structured browser, OS, and device information from the raw string.
Is user agent detection reliable for device targeting?
Partially. UA strings are the standard way to identify client software, but they can be modified or spoofed. For feature targeting in production applications, combine UA detection with JavaScript feature detection for more reliable results.
How do I find my browser's user agent string?
Open your browser's developer tools (F12 in most browsers), go to the Console tab, and type navigator.userAgent. Alternatively, check the Network tab: any HTTP request shows the User-Agent header in the request headers section.
What is the User-Agent Client Hints API and how does it affect UA parsing?
Chrome began reducing the information exposed in the traditional User-Agent string starting with Chrome 92, as part of Google's effort to reduce passive fingerprinting. As of Chrome 110+, the legacy UA string reports a frozen OS version and a reduced minor/build version number rather than the actual values. For example, a user on Windows 11 running Chrome 125 may have a UA string that reports Windows 10 and an older version pattern. The replacement is the User-Agent Client Hints API (navigator.userAgentData), which lets websites explicitly request specific device attributes through an active permission model rather than passive header inspection. For developers who need accurate current browser and OS versions from Chrome users, transitioning to UA-CH is the recommended path. Traditional UA string parsing still works for identifying the browser family and major version, and works fully for non-Chrome browsers. If your UA parser shows seemingly outdated Windows or Chrome version numbers, the UA reduction is likely the explanation.
Is my user agent information stored?
No. The UA string is parsed entirely in your browser. Nothing is sent to any server, and no data is stored.
The short version
A user agent parser translates the cryptic User-Agent header string into readable fields: browser, engine, OS, and device type. ToolHQ's free parser automatically reads your current browser's UA when you open the tool and parses any string you paste in, all in your browser with no server communication.
Whether you are debugging a compatibility issue, analyzing server logs, or identifying a bot, the parser gives you the structured information you need in seconds.
Parse any user agent string now
For broader network analysis, the DNS lookup tool and IP geolocation lookup complement UA parsing. The robots.txt generator helps you block specific bots once you have identified them. Browse all developer tools on ToolHQ.