User-agent parser · Guide
The User-Agent String Explained
The UA string is famously strange. A little history explains why it lists so many things.
A pile of compatibility tokens
Modern UA strings include tokens like Mozilla and KHTML, like Gecko for historical compatibility, alongside the actual browser and engine. That is why they look redundant — the cruft is intentional.
What to extract
The parts that matter are the real browser and version, the OS, and the device. A parser ignores the compatibility noise and surfaces those.
Frequently asked questions
Can I use this for production work?
Yes, for inspection, formatting and quick generation. Still review the output before committing it to production code or configuration.
Ready to try it?
Open the free browser-based User-agent parser and apply what you just read — no sign-up, runs locally.
Open the User-agent parser tool