Build a Social Media Caption Generator with ChatGPT

Build a Social Media Caption Generator with ChatGPT

Ever wish you could whip up a batch of catchy social media captions without staring at a blinking cursor? In this guide, you’ll learn how to build a simple (but powerful) automation that creates marketing-ready captions—based on your topics, tone, or products—using ChatGPT, Google Sheets, and n8n. No technical background necessary!

Why Automate This

Writing effective social media captions is time-consuming, and it’s easy to run out of ideas—especially if you need to post often or for multiple products. AI can help you brainstorm quickly and consistently, but doing this by hand is repetitive. That’s where automation comes in: set up your workflow once, and let AI handle the rest, so you can focus on running your business (or just save hours each week).

  • Batch create captions instantly for lots of topics or products.
  • Stay on brand by customizing tone and prompts.
  • Organize ideas in one spot—your trusty Google Sheet.
  • Cut out copy-pasting and manual repetitive tasks.

Step-by-Step Setup

Step 1: Collect Your Topics or Product Info in Google Sheets

Think of Google Sheets as your central hub. Each row is a new caption idea you need—like product names, campaign topics, or even customer testimonials. You don’t need fancy formatting, just a simple spreadsheet:

{
  "Product name": "Eco-Friendly Water Bottle",
  "Description": "Reusable, BPA-free, keeps drinks cool for 24 hours.",
  "Tone": "Playful"
}

Tip: Add columns like Image URL or Target Platform if you want even more context for ChatGPT later!

Step 2: Set Up the n8n Workflow to Watch Your Sheet

n8n is a free workflow tool that connects all your apps without code. We’ll tell n8n to keep an eye on your Google Sheet. Whenever you add a new row (caption request), n8n will notice and spring into action.

If you drew it as a flowchart, it might look like:

  • Google Sheets (trigger) → ChatGPT (generate) → Google Sheets (update with caption)
{
  "event": "new_row",
  "row": {
    "Product name": "Self-Cleaning Litter Box",
    "Description": "Automatic, odor-free, WiFi connected",
    "Tone": "Witty"
  }
}

Tip: You can filter out old rows or only trigger on blank caption cells so you don’t overwrite anything accidentally.

Step 3: Send Data to ChatGPT for Caption Generation

This is where the AI magic happens. In your workflow, add the OpenAI (ChatGPT) node and craft a prompt that works for your business. You want to give enough info—like product name, description, and the desired tone (fun, bold, cheeky, etc.).

{
  "prompt": "Write a playful social media caption for this product: Reusable, BPA-free water bottle that keeps drinks cool for 24 hours. Keep it under 20 words."
}

Tip: Try out prompts in the ChatGPT interface first, then use your favorite one in n8n. Want a list of options? Ask ChatGPT for 3 variations!

Step 4: Update Your Google Sheet with the AI-Generated Caption

Once ChatGPT replies, n8n grabs that answer and pastes it back into your sheet (in a new “Caption” column). This means your spreadsheet will fill up with fresh, AI-powered captions automatically—one for each product or campaign.

{
  "row_id": 7,
  "caption": "Sip sustainably and stay cool all day! 🧊💧 #EcoFriendly #HydrationGoals"
}

Tip: If you want, set up n8n to email you when a batch is ready, or automatically send the captions to your social media scheduler (like Buffer or Hootsuite).

Step 5 (Optional): Add Trend Data or Media Triggers

If you want even catchier captions, fetch trending topics or keywords with tools like Dumpling AI or Google’s autocomplete, then feed them into your sheet for more timely posts. Or monitor a folder in Google Drive or Dropbox for new images/videos and automatically generate relevant captions as soon as you upload new media.

{
  "media_url": "https://drive.google.com/waterbottle-pic.jpg",
  "trend": "stay hydrated this summer"
}

Tip: Captions that use seasonal or trending themes tend to get more engagement!

Real Example: Social Captions for New Product Launches

Let’s say you’re launching a new range of eco-friendly water bottles and want to announce them on Instagram and Facebook. Here’s how the workflow could go, step by step:

  1. You enter product details in your Google Sheet (names, colors, key features, desired tone).
  2. n8n notices each new row and grabs the relevant info.
  3. For each product, n8n sends a prompt like: “Give me a cheeky Instagram caption to promote our new blue water bottle. Emphasize eco-friendliness and summer vibes in under 20 words.”
  4. ChatGPT comes back with something like:

    Blue bottle, green planet! 🌍💙 Sip in style & save the earth. #EcoChic

  5. n8n adds this back to the “Caption” cell of your spreadsheet, ready for review or direct posting.

With this setup, you can add new products anytime—and within minutes, you’ll have AI-written posts ready to go.

Tools You’ll Need

  • ChatGPT account (or any OpenAI API-compatible AI)
  • Google Sheets (free and easy for lists)
  • n8n.io (workflow automation tool, free self-hosted or cloud)
  • Optional: Dumpling AI for trend suggestions, or access to the Google Trends/Autocomplete APIs

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Final Thoughts

You don’t need a background in tech or marketing to start automating your social media captions. Using tools like Google Sheets, n8n, and ChatGPT, you can keep your feed fresh—without burning out on creativity. Start small: one product, one platform, one automation. As you get comfortable, tweak your prompts and try out new triggers for trend or media-based posts. The best part? This system always works while you focus on things computers can’t do (yet): building real relationships with your customers.

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