User Agent Parser
Instantly parse user agent strings to extract browser, OS, device, and bot details.
Parse User Agent String
What is a User Agent?
A User Agent (UA) string is a snippet of text that a web browser (or any other application) sends to the web server it connects to. This string contains information about the application type, operating system, software vendor, and software revision.
Web servers use this information to serve different versions of a web page based on the device, such as sending a mobile-optimized layout when a mobile phone is detected, or for analytical purposes to understand what browsers their users are running.
Why parse User Agent strings?
Parsing UA strings allows developers to extract meaningful data from the raw text. Common use cases include:
- Analytics & Logging: Determining the breakdown of operating systems (Windows, macOS, iOS, Android) and browsers (Chrome, Safari, Firefox) visiting a site.
- Feature Detection Support: While feature detection is generally preferred over browser sniffing, UA parsing is sometimes necessary to apply workarounds for specific legacy browser bugs.
- Bot Detection: Identifying automated crawlers (like Googlebot or Bingbot) and malicious scrapers to filter out non-human traffic from analytics or apply rate limiting.
Client-Side Security & Privacy
This User Agent Parser runs completely within your web browser. When you paste a user agent string to analyze it or click "Use My User Agent", the data is parsed locally using JavaScript. It is never transmitted to an external server or stored in a database. Because it is a zero-dependency vanilla JS tool, it also works completely offline after the initial page load.