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

Is the User Agent Lookup tool free to use?
Yes — the BunchTool User Agent Lookup tool is completely free, runs offline, and requires no registration. Parse your full user-agent string to identify browser family, OS, and rendering engine.
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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