User Agent Checker: Browser Signature & Device Inspector

100% Free Developer 🔒 Client-Side Private
User Agent Checker: Browser Signature & Device Inspector
Interactive Client-Side Tool • 100% Free & Fast
Exact Age Breakdown
26 Years, 2 Months, 26 Days
Total Months
314
Total Days
9,584
Next Birthday in
96 Days

Every HTTP request sends a User-Agent header specifying the client browser version, rendering engine, and operating system architecture. 99tools User Agent Checker parses your browser telemetry in real time for QA testing, compatibility audits, and responsive design verification.

Quick Guide

How to Use User Agent Checker: Browser Signature & Device Inspector in 3-4 Simple Steps

1

Open User Agent Tool

Access the user agent inspector on 99tools in your target browser.

2

Review Detected Specs

Inspect browser name, rendering version, operating system architecture, and screen properties.

3

Copy UA String

Click Copy to export the exact User-Agent string for QA testing or bug reports.

Need Help?

Frequently Asked Questions

Everything you need to know about this tool, accuracy, formulas, and privacy.

What is a browser User-Agent string?
A User-Agent is an HTTP request header string that informs web servers about your browser vendor, rendering engine, and host operating system version.
Why do developers inspect User-Agent headers?
Developers check user-agent headers to test responsive CSS layouts, debug browser-specific compatibility bugs, and verify bot or crawler user-agents.

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