User-Agent Parser

Parse a User-Agent string into browser, version, operating system, device type, and bot status

Input

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Output

Output will appear here...

What is User-Agent Parser

Written by Giorgos Kostas. Last reviewed: April 18, 2026

User-Agent Parser inspects a User-Agent string and extracts the browser family and version, operating system, device type (desktop / mobile / tablet), and detects common bots and crawlers.

It's useful when auditing analytics, debugging feature-detection issues, or triaging abuse reports.

Why use it

Debug browser-specific UA bugs.
Audit bot traffic in server logs.
Verify feature detection fallbacks.
Triage abuse reports with known patterns.
Teach UA anatomy to new engineers.

Features

Browser + version detection
OS + version detection
Desktop / mobile / tablet
AI-crawler detection
All User-Agent Parser work stays on your device

How to use User-Agent Parser

Paste UA. Drop a User-Agent string.
Run. Get browser, OS, device, bot status.
Use in logs. Cross-check against analytics data.

Example (before/after)

User-Agent

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2 Safari/605.1.15

Parsed

Browser            Safari 17.2
Operating system   macOS 10.15.7
Device type        Desktop
Bot / crawler      No
Raw                Mozilla/5.0 …

Common errors

Spoofed UAs

UAs are user-controlled and can be faked.

Fix: Never use UA for security decisions — prefer capability detection.

Unknown browsers

Niche browsers may report as Unknown.

Fix: Extend the pattern list or use a full UA database.

FAQ

Which browsers are detected?

Chrome, Firefox, Safari, Edge, Opera, and bots / crawlers.

Is input uploaded?

No — parsing is client-side.

Does it detect AI crawlers?

Yes — GPTBot, Anthropic / Claude, Google-Extended, and Perplexity-Bot are flagged.

Can I rely on UA for auth?

No — UA is trivially spoofed. Use real auth signals.

Is this a full UA database?

No — it covers common patterns. Use ua-parser-js for an exhaustive match.

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