User-Agent Parser Guide
Reference for parsing User-Agent strings into browser, OS, device, engine, and bot-style signals for debugging.
Quick answer
Use the User-Agent Parser to summarize browser, operating system, device class, rendering engine, and possible bot signals from a pasted User-Agent string.
What this tool does
The parser helps interpret logs, bug reports, analytics samples, and crawler checks. It does not identify a real person.
Step-by-step use
- Paste the User-Agent string.
- Review browser and version hints.
- Review OS and device hints.
- Check whether the string looks like a bot or automation client.
- Compare with headers, route, and timestamp context before drawing conclusions.
Data handling and processing behavior
Processing is handled in the browser for this tool based on the current public implementation. Avoid pasting logs that include personal data unless you have reviewed your own privacy requirements.
Examples
Bug report
Check whether an issue came from mobile Safari, desktop Chrome, or an embedded browser.
Crawler review
Inspect whether a request claims to be a search bot before comparing server logs.
Analytics review
Use parsed browser family and device class as broad signals. Avoid treating the User-Agent as a stable user ID, because strings can be spoofed, shortened, or changed by browser updates.
Assumptions and limits
- User-Agent strings can be spoofed.
- Parsing does not prove identity or intent.
- Bot detection needs multiple signals, not only one header.
- Full logs may include personal data and should be handled carefully.
Common errors
Trusting the string completely
A User-Agent is a claim from the client, not a verified identity.
Ignoring surrounding context
Route, timestamp, IP range, and request pattern matter for analysis.
Next steps
- User-Agent Parser — inspect browser and device hints
- HTTP Header Parser — review related headers
- URL Parser — inspect requested URLs