BunchTool — User Agent Lookup
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🕵️ Raw User Agent String
📋 Decoded Agent Parameters
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User Agent Lookup —
Comprehensive User-Agent Header Parser

Inspect and decode your browser's User-Agent string with our free User Agent Lookup tool. Extract browser name, operating system platform, rendering engine, and architecture tokens with 100% offline privacy.

Raw navigator.userAgent string extraction & 1-click clipboard copy
Browser vendor detection (Chrome, Firefox, Safari, Edge)
Operating system platform identification (Windows, macOS, Linux, Android, iOS)
100% client-side execution — zero UA strings transmitted to external servers
🕵️
HTTPHeader
FreeAlways
0 LogsPrivate
How It Works

Inspect User-Agent in three easy steps

Step 1
🕵️
View Raw UA Header

The tool extracts navigator.userAgent automatically on page load.

Step 2
📋
Inspect Decoded Cards

Review extracted tokens categorizing Browser, OS, Rendering Engine, and Platform.

Step 3
📋
Copy to Clipboard

Click Copy User Agent to copy your complete raw UA string for debugging.

Why BunchTool

Why use our free User Agent Lookup tool?

🕵️
Raw User-Agent Header Extraction

Extracts exact navigator.userAgent strings for HTTP request debugging and cross-browser testing.

⚙️
Tokenized Browser & OS Parsing

Parses layout engines (Gecko, WebKit/Blink), operating systems, and vendor tokens without server calls.

🔒
100% Offline, Zero Telemetry

User-Agent inspection runs entirely inside browser memory. No device signatures are sent to external analytics.

FAQ

Frequently asked questions

Are there any usage limits, premium tiers, or hidden fees for the User Agent Lookup?
Yes. All analysis metrics and utility functions for the User Agent Lookup process data locally inside your web browser. Zero user inputs or URLs are stored or tracked.
What is a User-Agent string?
A User-Agent string is a text header transmitted by web browsers to HTTP servers that identifies browser version, operating system, rendering engine, and device architecture.
Why do user agents contain 'Mozilla/5.0'?
For legacy compatibility. Historical browsers appended 'Mozilla/5.0' to prevent web servers from serving degraded content intended for non-Netscape browsers.
Does this tool transmit my User-Agent string to external servers?
No. The tool reads navigator.userAgent and parses all tokens strictly inside local browser memory.
Detailed Guide

Understanding User-Agent Headers, Client Hints Migration & UA Token Structure

The User-Agent request header follows RFC 7231 syntax: Mozilla/5.0 (Platform; OS) Engine/Version Browser/Version. Tokens reveal operating system build types, rendering engine numbers, and browser vendor release cycles.

To combat passive browser fingerprinting, modern standards bodies are phasing out detailed User-Agent strings in favor of User-Agent Client Hints (UA-CH) (navigator.userAgentData), which require explicit opt-in headers to access fine-grained device data.

Understanding UA strings remains vital for web developers diagnosing cross-browser compatibility issues, polyfill loading strategies, and server-side device routing rules.

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