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Generate Random User Agent - Custom Script

Dec 19, 2024 3 min read

A small custom TypeScript utility for generating newer, randomized browser user agents instead of relying on stale package defaults.

TypeScriptAutomationNPMUser Agent

I tried different npm package but they gives me old user agent. Here how i create random user agent using my own function

// generateUserAgent.ts
export function generateUserAgents(count: number): string[] {
    const userAgents: string[] = [];
    const baseOS = [
        "X11; Linux i686",
        "X11; Linux x86_64",
        "X11; Ubuntu i686",
        "X11; Ubuntu x86_64",
        "X11; Fedora i686",
        "Macintosh; Intel Mac OS X 10_15_7",
        "Macintosh; Intel Mac OS X 13_5",
        "Macintosh; Intel Mac OS X 14_0",
        "Windows NT 10.0; Win64; x64",
        "Windows NT 11.0; Win64; x64"
    ];
    // const baseChromeVersion = 111;
    const subVersionMax = 500;
    const webkitVersion = "537.36";
    const safariVersion = "537.36";

    for (let i = 0; i < count; i++) {
        const os = baseOS[Math.floor(Math.random() * baseOS.length)];
        const chromeVersionMajor = Math.floor(Math.random() * (115 - 111 + 1)) + 111;
        const chromeVersion = `${chromeVersionMajor}.${Math.floor(
            Math.random() * subVersionMax
        )}.${Math.floor(Math.random() * 100)}`;
        const userAgent = `Mozilla/5.0 (${os}) AppleWebKit/${webkitVersion} (KHTML, like Gecko) Chrome/${chromeVersion} Safari/${safariVersion}`;
        userAgents.push(userAgent);
    }
    return userAgents;
}

generateUserAgents(1000);

Result:

Mozilla/5.0 (X11; Ubuntu x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.259.40 Safari/537.36
Mozilla/5.0 (X11; Fedora i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.357.58 Safari/537.36
Mozilla/5.0 (X11; Fedora i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.455.72 Safari/537.36
Mozilla/5.0 (X11; Fedora i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.480.49 Safari/537.36
Mozilla/5.0 (X11; Linux i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.443.60 Safari/537.36
Mozilla/5.0 (X11; Ubuntu i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.465.80 Safari/537.36
Mozilla/5.0 (X11; Ubuntu i686) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.295.6 Safari/537.36
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.269.50 Safari/537.36
Mozilla/5.0 (Macintosh; Intel Mac OS X 13_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.76.94 Safari/537.36
Mozilla/5.0 (X11; Ubuntu x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.299.94 Safari/537.36

Here is result of 10 thousand random user agents, you can see on my github gist - Click Here.

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Written by Rahul Vishwakarma — this is the first-party home for this article on rahulxf.com.