Free User Agent Parser - Lookup & Decode Any UA String
Mozilla/5.0, and nearly impossible to read at a glance. The APIFreaks User Agent Parser fixes that. Paste any UA string and this free user agent lookup tool instantly decodes it into clearly labeled components: browser name and version, device type and brand, rendering engine, and operating system. Results appear in a structured layout and as copyable JSON for your own workflows. Whether you are a web developer debugging cross-browser issues, a QA engineer validating test environments, or a security analyst inspecting server logs, you get the parsed data you need in seconds. No sign-up required.Comprehensive User Agent String Parsing
When you submit a user agent string to the APIFreaks User Agent Lookup tool, the response is organized into four clear categories:
Browser or Agent Details
This online user agent parser identifies the browser or client software encoded in the UA string. You receive the browser name (for example, Firefox, Chrome, or Safari), its general type (Browser, Robot, or application-level client), and the full version number alongside the major version. This information helps you determine exactly which software generated the request.
Device Details
The device section reveals the hardware behind the UA string. It reports the device name (such as Linux Desktop, Apple iPhone, or Samsung Galaxy), the device category (Desktop, Phone, Tablet, or Console), the manufacturer brand, and the CPU architecture (for example, Intel x86_64 or ARM). This is essential for understanding how your content will render on the user's hardware.
Engine Details
Rendering engines dictate how a browser interprets HTML, CSS, and JavaScript. This online user agent parser extracts the engine name (Gecko, Blink, WebKit, or others), the engine type, and its version. Knowing the engine version lets you check compatibility with specific web standards and diagnose rendering bugs tied to a particular engine build.
Operating System Details
The OS section shows the operating system name (Windows, macOS, Ubuntu, Android, iOS), its type (Desktop, Mobile, or Cloud), the version number, and the build identifier where available. Fields that cannot be determined from the string are marked with '??' so you always know exactly which data points are present and which are missing.
JSON Output
In addition to the visual breakdown, this user agent decoder provides the full parsed result as a JSON object. You can copy this output directly into your scripts, log analysis pipelines, or testing frameworks without any manual reformatting.
How to Use This Tool?
- Step 1 - Get the user agent string you want to decode: Copy it from your server access logs, a support ticket, an analytics report, or an HTTP request header. To check your own browser instead, click “Check My User Agent”: the tool detects the user agent your browser sent with the request, fills it in, and parses it in one step, so you can jump straight to the results.
- Step 2 - Enter the User Agent String: Paste any valid UA string into the input field. For example: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:149.0) Gecko/20100101 Firefox/149.0
- Step 3 - Click "User Agent Lookup": This user agent checker processes the string and returns the parsed output instantly.
- Review the Results: Browse the Browser, Device, Engine, and Operating System sections to find the details you need.
- Copy the JSON Output (optional): Use the JSON view for programmatic access or to paste the structured data into your development environment.
Why use a Browser User Agent Lookup?
Cross-Browser Debugging
When a website behaves differently on certain browsers, paste the reported user agent into this tool to confirm the exact browser name, version, and rendering engine. This eliminates guesswork and helps you reproduce and fix issues faster.
Server Log Analysis
Web server access logs record the user agent of every visitor. Use this tool to decode UA strings from your logs and understand the mix of browsers, operating systems, and devices accessing your site.
Bot and Crawler Identification
Search engines, scrapers, and automated tools send their own user agent strings. Parsing these strings helps you distinguish legitimate crawlers like Googlebot from suspicious or malicious bots trying to access your resources.
QA and Testing Validation
During cross-device testing, verify that your test environment is sending the correct user agent. This is especially useful when you are spoofing user agents to simulate mobile devices or older browser versions.
Analytics Verification
Analytics platforms rely on user agent data to segment traffic by browser and device. Use this tool to double-check how specific UA strings are classified, ensuring your analytics reports are accurate.
Content Negotiation Debugging
If your application serves different content or layouts based on the user agent, parse the incoming UA string to verify that the correct content variant is being delivered.
Security Auditing
Malformed or unusual user agent strings can indicate injection attempts or automated attacks. Parsing these strings helps security teams identify anomalies and take appropriate action.
Mobile Optimization
Identify whether a visitor is on a phone, tablet, or desktop, along with the exact device brand and OS version. This information helps you optimize layouts, media queries, and resource loading for specific audiences.
What is a User Agent String?
A user agent string is a piece of text that every web browser, mobile app, and automated bot includes in the HTTP headers of their requests to web servers. This string serves as a digital introduction, telling the server what software is making the request, which operating system it runs on, and what type of device it is being sent from.
A typical user agent string looks like this:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36This string may appear confusing because it references multiple browser names - Mozilla, Chrome, and Safari - in a single line. This is a historical quirk dating back to the early browser wars of the 1990s, when websites served different content based on the browser name. To ensure compatibility, newer browsers began including older browser tokens in their UA strings. Today, nearly every browser includes "Mozilla/5.0" as a prefix, which is why manual interpretation of these strings is so unreliable.
Web servers use user agent strings to determine which version of a page to serve (desktop vs. mobile), to collect analytics about visitor demographics, and to identify automated bots. The APIFreaks User Agent Lookup tool decodes this complex string into its real, meaningful components so you can focus on the data that matters.
User Agent Strings and Client Hints
Sec-CH-UA, Sec-CH-UA-Platform, and Sec-CH-UA-Model, which servers must explicitly request. A user agent parser remains the right tool for the UA strings that dominate today's traffic and historical server logs, but if you control the server, pairing UA parsing with Client Hints gives you the most complete picture on Chromium traffic.Why Choose APIFreaks for User Agent Parsing?
Comprehensive Four-Section Breakdown
Unlike many competitors that return only browser and OS information, this tool provides a full four-section output covering browser details, device information, rendering engine data, and operating system specifics - all in one lookup.
JSON Output Included
Every result includes a ready-to-use JSON object, making it easy to integrate parsed data into scripts, applications, or analytical workflows without manual reformatting.
Bot and Threat Detection
This online user agent parser identifies known crawlers and bots and can flag malformed user agent strings that may indicate injection attacks - a level of anomaly flagging most free user agent checkers do not offer.
No Sign-Up Required
Get instant results without creating an account, entering an email address, or dealing with usage limits for casual lookups.
Backed by a Full API
When you need to parse user agents at scale, the APIFreaks User Agent Parser API delivers the same structured data via a simple GET request. A Bulk User Agent Parser API is also available for processing multiple strings in a single call.
Accurate and Up-To-Date
The underlying parsing engine is regularly updated to recognize new browser versions, device models, and crawler signatures, ensuring reliable results for modern user agent strings.
Frequently Asked Questions
The fastest way is to click the “Check My User Agent” button on this page: it reads the User-Agent header your browser sent with the request, fills it into the input, and parses it in one step.
You can also type navigator.userAgent into your browser's developer console (F12 → Console), or read the User-Agent header on any request in the Network tab. Whichever way you get the string, paste it into this user agent string parser to see exactly how servers classify your browser, device, and operating system.
This tool is a free, web-based interface designed for quick, one-off lookups. The User Agent Parser API is built for developers who need to parse user agent strings programmatically, in bulk, or as part of an automated workflow. The API returns the same structured data and supports integration into any application. For processing up to 100 strings per request, use the Bulk User Agent Parser API.
This tool parses the classic User-Agent header string, which is still sent by every browser and recorded in virtually all server logs. User-Agent Client Hints (Sec-CH-UA headers) are separate request headers that Chromium browsers send only when a server requests them, so they do not appear inside the UA string itself. If your logs capture Client Hints headers, use them alongside the parsed UA data for the most precise picture of Chromium traffic.
Process hundreds of user agent strings in a single request with the Bulk User Agent Parser API. Sign up for your free API key today.
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