How to use User-Agent
- 1. Paste a UA. From logs or DevTools.
- 2. Read browser/OS/device. Best-effort.
- 3. Don't block on UA. Client hints and feature detect are more honest.
- 4. Copy JSON. Local only.
About this tool
User-Agent is a messy, spoofable string. Parsing it is still useful for log analytics and reproducing a bug. It is a bad authorization signal.
Lies
Bots and privacy tools rewrite UA. Treat the parse as a hint.
Client Hints
This tool does not call UA-CH. It parses the classic header only.
Code examples
Header
User-Agent: Mozilla/5.0 ...