browser_headers

Generates randomized but response-stable "browser-like" HTTP headers for Dart applications. Perfect for extracting data from the web.

Features

• Always includes a random, realistic User-Agent - Uses realistic browser user agents
• Randomly includes coherent optional header groups - Groups like Sec-Fetch-* appear together naturally
• Avoids changing response semantics - Fixed Accept-Language, safe encodings
• Supports search referrers - Generate search engine referrer URLs with properly encoded queries
• Allows caller overrides - Override any generated header via baseHeaders

Usage

Basic usage

import 'package:browser_headers/browser_headers.dart';
import 'package:http/http.dart' as http;

void main() async {
  // Generate browser-like headers
  final headers = BrowserHeaders.generate();

  final response = await http.get(
    Uri.parse('https://example.com'),
    headers: headers,
  );

  print('Status: ${response.statusCode}');
}

With search referrer

Generate headers with a referrer that looks like it came from a search engine:

final headers = BrowserHeaders.generate(
  refererQuery: 'zillow 11222 Dilling Street',
);

// The Referer header will be one of:
// - https://www.google.com/search?q=zillow%2011222%20Dilling%20Street
// - https://www.bing.com/search?q=zillow%2011222%20Dilling%20Street
// - https://duckduckgo.com/?q=zillow%2011222%20Dilling%20Street
// - https://search.yahoo.com/search?p=zillow%2011222%20Dilling%20Street

The query string is properly URL encoded and uses the correct query parameter for each search engine (q for most, p for Yahoo).

With custom overrides

Override any generated header:

final headers = BrowserHeaders.generate(
  refererQuery: 'my search',
  baseHeaders: {
    'User-Agent': 'MyCustomUA/1.0',
    'Accept-Language': 'en-GB,en;q=0.9',
  },
);

How it works

The package generates headers in coherent groups:

Core headers (always included):

• User-Agent - Random realistic browser UA
• Accept - Standard browser accept string
• Accept-Language - Fixed to en-US,en;q=0.9

Optional groups (randomly included together):

• Encoding group: Accept-Encoding, Connection
• Security group: Cache-Control, Upgrade-Insecure-Requests, Sec-Fetch-Mode, Sec-Fetch-Site, Sec-Fetch-User, Sec-Fetch-Dest
• Referrer: Either a search engine homepage or search URL (if refererQuery provided)

This ensures headers appear natural and coherent, like they came from a real browser.