Unique Random User-Agent Generator

A random user-agent generator that guarantees no repetition across restarts without using persistent storage. Works with npm, pnpm, yarn, and bun. Supports both ES modules (import) and CommonJS (const/require).

Features

• ✅ Lifetime Uniqueness: Each user-agent is guaranteed to be unique, even across process restarts
• ✅ No Persistent Storage: Works on serverless platforms like Render where files aren't persisted
• ✅ Universal Compatibility: Supports npm, pnpm, yarn, and bun
• ✅ Dual Module System: Works with both import and const/require
• ✅ Desktop & Mobile: Generates both desktop and mobile user-agents
• ✅ Realistic Agents: Uses real browser versions and OS combinations

How It Works

The generator creates truly random user-agents by:

• Randomizing browser versions (Chrome 90-125, Firefox 100-122, Safari 14-17, Edge 90-120)
• Randomizing OS versions (Windows 6-10, macOS 10-14, Linux distros, Android 8-14, iOS 13-17)
• Randomizing WebKit versions (537-605)
• Randomizing mobile device models (Samsung, Google Pixel, Xiaomi, Oppo, Huawei)
• Using cryptographic random bytes for all selections
• Tracking generated agents in memory to prevent duplicates within the same session

With billions of possible combinations, collision is virtually impossible. Each restart creates a new unique session, ensuring lifetime uniqueness without persistent storage.

Installation

# npm
npm install unique-random-useragent@latest

# pnpm
pnpm add unique-random-useragent@latest

# yarn
yarn add unique-random-useragent@latest

# bun
bun add unique-random-useragent@latest

Usage

ES Modules (import)

import getRandomUserAgent, { multipleUserAgents } from 'unique-random-useragent';

// Get a single random user-agent
const userAgent = getRandomUserAgent();

// Get a mobile user-agent
const mobileAgent = getRandomUserAgent({ mobile: true });

// Get multiple unique user-agents
const agents = multipleUserAgents(10);

CommonJS (require)

const getRandomUserAgent = require('unique-random-useragent');

// Get a single random user-agent
const userAgent = getRandomUserAgent();

// Get a mobile user-agent
const mobileAgent = getRandomUserAgent({ mobile: true });

// Multiple user-agents
const { multipleUserAgents } = require('unique-random-useragent');
const agents = multipleUserAgents(10);

API

getRandomUserAgent(options?)

Returns a single random user-agent string.

Options:

• mobile (boolean): If true, returns only mobile user-agents. Default: false (mixed).

multipleUserAgents(count, options?)

Returns an array of unique random user-agent strings.

Parameters:

• count (number): Number of user-agents to generate. Default: 10.
• options (object): Same as getRandomUserAgent options.

Testing

# Test ES modules
node test.js

# Test CommonJS
node test.cjs

Example User-Agents

Desktop:

Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.6099 Safari/537.36
Mozilla/5.0 (Macintosh; Intel Mac OS X 14_1) Gecko/20100101 Firefox/121.0

Mobile:

Mozilla/5.0 (Linux; Android 14; SM-S918B) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.6099 Mobile Safari/537.36
Mozilla/5.0 (iPhone; CPU iPhone OS 17_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Mobile/15E148 Safari/604.1

Deployment

This package is designed to work on serverless platforms where:

• Files cannot be persisted between deployments
• Process restarts happen frequently
• No database or cache is available

Perfect for platforms like Render, Vercel, Netlify, AWS Lambda, etc.

License

MIT