user_agent

A pure Dart user-agent string parser with browser, OS, device type, and bot detection.

Features

• Pure Dart — no native dependencies
• Browser detection with version extraction
• Operating system detection with version parsing
• Device type classification (desktop, mobile, tablet, bot)
• Extensive bot detection (search engines, AI crawlers, testing frameworks, HTTP clients)

Installation

dependencies:
  user_agent: ^1.0.0

Usage

Parsing a User-Agent String

import 'package:user_agent/user_agent.dart';

final ua = UserAgent.parse(
  'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) ...',
);

print(ua.browser);        // Browser.chrome
print(ua.browserVersion); // "120.0.0.0"
print(ua.os);             // OperatingSystem.macOS
print(ua.osVersion);      // "10.15.7"
print(ua.deviceType);     // DeviceType.desktop

Convenience Checks

if (ua.isBot) {
  return Response.forbidden('Bots not allowed');
}

if (ua.isMobile) {
  // Serve mobile layout
}

if (ua.isDesktop) {
  // Serve desktop layout
}

With Shelf Requests

Response handleRequest(Request request) {
  final ua = UserAgent.parse(
    request.headers['user-agent'] ?? '',
  );
  print('${ua.browser.displayName} on ${ua.os.displayName}');
  return Response.ok('Hello');
}

Bot Detection

The parser detects a wide range of bots:

• Search engines — Googlebot, Bingbot, DuckDuckBot, YandexBot
• Social media — facebookexternalhit, Twitterbot, LinkedInBot
• AI crawlers — GPTBot, ClaudeBot, PerplexityBot
• Testing frameworks — Puppeteer, Selenium, Playwright
• HTTP clients — curl, wget, python-requests, axios

Enums

Browser — chrome, firefox, safari, edge, opera, samsungInternet, ie, vivaldi, brave, ucBrowser, yandex, wechat, twitter, unknown

OperatingSystem — windows, macOS, linux, android, iOS, chromeOS, windowsPhone, unknown

DeviceType — desktop, mobile, tablet, bot, unknown

All enums have a displayName property for human-readable output.