How it works
User-Agent detection is heuristic and can be spoofed. Prefer feature detection and client hints for application behavior.
Apply ordered browser, OS and device signatures to the input string.
Debugging scenario
Paste a synthetic or public test User-Agent that reproduces a display issue. Compare the heuristic browser, operating-system and device labels with feature detection, responsive layout behavior and server logs before changing application logic.
How to interpret the result
The parser recognizes a short ordered list of common signatures. User-Agent strings are legacy hints, can be frozen or spoofed and often contain compatibility tokens for other browsers. The result does not report exact versions and should not gate authentication, authorization or security controls.
Input reference
- User-Agent
- Example default: Sample input included
Common mistakes
- Pasting secrets, credentials, customer records or other production data into a browser tool or shareable URL.
- Blocking users or changing security behavior solely from a heuristic User-Agent classification.
- Treating a convenient preview as validation by the target runtime, parser, database or security control.
Before using the result
- Reduce the input to a synthetic example that still reproduces the behavior.
- Prefer capability detection and test responsive behavior on actual supported browser versions.
- Add the accepted input and expected output to the project regression tests before release.
Questions to check before production use
Is parsing exact?
No. User-Agent strings vary and can be spoofed; treat output as a hint.
Is my User-Agent uploaded?
No. The sample is parsed locally.
Independent developer utility. Review output before using it in production.