I’m a heavy X user, and replying to posts was eating up my days. Chatting with followers or answering customer questions felt like a chore. So, I decided to build something to handle it: a Chrome extension that uses xAI’s Grok to auto-generate replies. Now, I get 50 free replies a month and save hours. Here’s how I made it—and what I learned along the way.

Why X and a Chrome Extension?

X is fast-paced—your replies need to be quick and on point to keep the conversation going. I wanted a tool that fits right into my browser and spits out natural responses. A Chrome extension was the obvious pick: lightweight, easy to share, and perfect for hooking into X’s interface. For the AI part, I went with Grok—it’s fast, clever, and churns out human-like text.

How It Works

Frontend: Plain JavaScript to watch X’s page. It spots when I’m about to reply by tracking DOM changes.

AI Magic: I tap into Grok’s API (assuming that’s how it’s delivered), sending the post text and getting a reply back in 1-2 seconds.

UI: Just a button next to the reply box—click it, see the AI’s suggestion, and tweak or send it.

A Peek at the Code

Here’s how I listen for reply boxes:

document.addEventListener('DOMNodeInserted', (e) => {
    if (e.target.classList.contains('reply-box')) {
        addReplyButton(e.target);
    }
});

And here’s the API call:

async function getReply(postText) {
    const res = await fetch('https://api.x.ai/grok', {
        method: 'POST',
        body: JSON.stringify({ text: postText })
    });
    return res.json().reply;
}

Making It Snappy

Speed matters, so I cache common reply patterns locally.

Privacy’s big too—all the heavy lifting happens on the user’s machine (or anonymized if it’s server-side).

Bumps in the Road

Generic Replies: Early on, Grok spat out stuff like “Cool post!”—way too basic. I tweaked the prompts with context like “match my vibe” or “keep it short” to get better fits.

Permissions: Getting the extension to play nice with X’s DOM took some trial and error. Here’s the slimmed-down manifest.json:

{
    "permissions": ["activeTab", "https://x.com/*"]
}

Why 50 Free Replies?

I wanted this to be useful for everyone, not just me. The free plan gives you 50 replies a month—plenty for casual users. Power users can upgrade if they want more (assuming there’s a paid tier). It’s also a great way to get feedback and keep improving.

Give It a Spin!

If you’re bogged down by X replies, check out my extension: intellireply.app. It’s live on the Chrome Web Store—install it and let Grok handle the typing. I’d love to hear what devs think—what’d you add? Multi-language support? Deeper context? Hit me up!

Wrap-Up

This little project showed me how automation can reclaim your time. Grok’s language chops paired with a Chrome extension solved a real pain point for me. Hopefully, it sparks some ideas for your next build. Got thoughts or questions? Drop them below—let’s chat!