Decoding a User-Agent String
Overview
Every browser sends a user-agent string with each request — a dense line of text that names the browser, its version, the operating system, and the device. It's useful for debugging and analytics but hard to read at a glance. This parser breaks a user-agent string into clear parts (browser, OS, device type, engine) instantly in your browser, with nothing uploaded.
How to Use (Step by Step)
- 1
Paste the user-agent string
Copy the string from your browser, a log, or a request header and paste it in.
- 2
Read the parsed breakdown
See the browser, version, operating system, rendering engine, and device type.
- 3
Use the details
Apply the parsed fields to your debugging, analytics, or detection work.
How It Works
You paste a user-agent string and the tool matches its patterns against known browsers, rendering engines, operating systems, and device signatures. It extracts fields like browser name and version, OS and version, and whether the device is a phone, tablet, or desktop. The parsing runs locally in JavaScript, so the string — which can reveal details about a user's setup — never leaves your device.
When to Use This
Debugging why a site behaves differently for one visitor. Checking what browser and OS a support ticket came from. Understanding analytics or server-log entries. Testing how your own browser identifies itself. Verifying that a bot or crawler is what it claims to be. Building or checking device-detection logic.
Frequently Asked Questions
Your browser sends it automatically; you can see it in developer tools under the network tab, via a 'what is my user agent' page, or by pasting navigator.userAgent in the console.
Important Notes
User-agent strings are messy and increasingly reduced for privacy (client hints are replacing some detail). Parsing is best-effort, and unusual or new browsers may be misidentified.