Automate Instagram Content Creation with n8n and Google Gemini

Opening Problem Statement

Meet Onur, a social media manager juggling multiple brands and struggling to keep up with the demand for fresh, engaging Instagram content. Every week, Onur spends hours brainstorming post ideas, crafting captions, sourcing or creating images, and scheduling them manually. This tedious process not only drains time but also increases the risk of missing deadlines, inconsistent messaging, and lost engagement opportunities.

For Onur, failing to post regularly means losing audience attention and reducing brand visibility, which directly impacts campaigns and sales. The challenge: how to automate creative content generation tailored specifically for Instagram that fits his brand voice and audience — without losing the human touch?

What This Automation Does

This n8n workflow revolutionizes Instagram content creation by combining AI-driven creativity with automated publishing. When triggered on a scheduled interval, it:

• Fetches the next post idea from a Google Sheet marked as ready to process (Status=0)
• Prepares essential input variables like topic, audience, brand voice, and target platform
• Uses Google Gemini AI to generate a unique, platform-specific content concept with a “Single Image” format focus
• Elaborates two detailed, visually distinct AI image generation prompts optimized for Instagram style
• Generates a concise, engaging caption tailored for Instagram’s audience and post style, including relevant hashtags
• Sends the chosen image prompt to the Replicate Flux AI model to create a striking, custom social media image
• Uploads the generated image and caption to Instagram via Facebook Graph API, handling media container creation, processing wait time, and post publishing
• Marks the processed post idea as completed in Google Sheets to avoid duplicate posts

With this workflow, Onur saves roughly 4-6 hours per post cycle and eliminates repetitive manual tasks while maintaining high-quality, brand-aligned posts.

Prerequisites ⚙️

• n8n automation platform account with access to create workflows
• Google Sheets account with a prepared spreadsheet tracking post ideas, including columns: Topic, Audience, Voice, Platform, and Status 📊
• Google Sheets OAuth2 credentials connected to n8n
• Google Gemini API access for AI-driven content concept and caption generation 🔑
• Replicate API account and token for AI image generation model (‘Flux 1.1 Pro Ultra’) 🔐
• Facebook Graph API credentials connected to the Instagram Business account for media upload and publishing 📧
• Basic Instagram Business account with necessary permissions for the Graph API
• Optional: Self-hosting n8n instance for full control and scale (consider services like Hostinger)

Step-by-Step Guide

Step 1: Set up Scheduled Trigger to Check for New Posts

In n8n, click + Create → Trigger Nodes → Schedule Trigger. Configure it to run at your preferred interval (e.g., daily or hourly). This node initiates the workflow each time based on the schedule, automatically checking for new posts to process.

Common mistake: Forgetting to enable or start the workflow after setup, causing no automation to run.

Step 2: Retrieve Next Post Idea from Google Sheets

Add the Google Sheets node labeled “1. Get Next Post Idea from Sheet.” Connect your Google Sheets OAuth2 credentials and select the target spreadsheet and sheet by name or ID. Configure the node to filter rows where Status=0, meaning new ideas that haven’t been processed yet.

You should see one row returned with columns like Topic, Audience, Voice, and Platform.

Tip: Ensure your sheet is shared with the Google OAuth account used in n8n and that data ranges are correct.

Step 3: Prepare Input Variables

Use a Set node called “2. Prepare Input Variables (Topic, Audience, etc.)”. Map the Google Sheets columns from the previous node to variables you’ll use downstream:

• Topic
• TargetAudience
• BrandVoice
• Platform (Instagram or LinkedIn)

This standardizes inputs for the AI nodes.

Step 4a: Generate Unique Content Concept Using Google Gemini

Insert the Chain LLM node “3a. Generate Content Concept (Gemini)” using the Langchain integration for Google Gemini. Paste the detailed prompt designed to generate one creative, platform-tailored “Single Image” content concept focused on engagement and originality.

The prompt specifically asks Gemini to consider the Topic, Audience, Brand Voice, and Platform for Instagram or LinkedIn, and to avoid clichés like typical quotes.

The output is a JSON object containing exactly one content concept string for the post.

Step 4b: Generate AI Image Prompt Options

Next, the “3b. Generate Image Prompt Options (Gemini)” Chain LLM produces two detailed, distinct prompts for AI image generation. It expands on the concept from 4a, tailoring visuals to the Instagram style (ethereal or bold options in this example) including composition, mood, color schemes, and lighting.

This node’s output is a JSON with an elaborated post concept and an array of two prompt options detailing image generation instructions suitable for Replicate’s Flux model.

Step 5: Generate a Post Caption Tailored to Instagram

Using the “3c. Generate Post Caption (Gemini)” Chain LLM node, n8n passes the image prompt, concept, and audience info to Gemini’s caption writer. It returns a platform-optimized caption with hashtag suggestions relevant to the content.

This text output is crucial for authentic engagement on Instagram.

Step 6: Create AI-Generated Image

Send the first image prompt option to the HTTP Request node “4. Generate Image using Prompt 1 (Replicate Flux).”

Configure it with a POST request to the Replicate API endpoint for the Flux model, using the detailed prompt from the earlier node. The response contains a URL to the processed image.

Common error: API key misconfiguration or duplicate requests without waiting can cause failures.

Step 7: Prepare Data for Instagram API Upload

Map the image URL and caption into a format suitable for Instagram’s Graph API using another Set node “5. Prepare Data for Instagram API.”

Step 8: Upload and Publish Image on Instagram

Use the Facebook Graph API node “6a. Create Instagram Media Container” to upload the image and caption. Upon success, it returns a container ID.

Then, the workflow waits briefly (Wait node “6b”) to allow Instagram to process the media.

Finally, the “6c. Publish Post to Instagram” node publishes the post using the container ID.

Step 9: Mark the Post Idea as Completed in Google Sheets

The last Google Sheets node “7. Update Post Status in Sheet” finds the corresponding row and sets the Status column to 1 to indicate the post was published.

This prevents reposting the same concept.

Customizations ✏️

• Switch Target Platform: Change the Platform field in the Google Sheet and ensure the AI prompt respects the new platform’s content norms (e.g., LinkedIn’s professional tone). Adjust or add prompts in the “3a. Generate Content Concept” node accordingly.
• Use the Second Image Prompt Option: Modify the HTTP request node “4. Generate Image using Prompt 1” to use the second prompt (prompt_options[1].prompts[0]) to experiment with different visual styles from the AI.
• Adjust Posting Schedule: Change the Schedule Trigger node’s interval for more frequent or less frequent post generation according to your content calendar needs.
• Change Caption Style: Customize the “3c. Generate Post Caption” prompt text to be more playful, formal, or promotional, depending on brand voice.
• Add Multiple Platforms: Extend the Google Sheets with additional platform options and branch the workflow to post images on LinkedIn or other social media using respective APIs.

Troubleshooting 🔧

Problem: “Google Sheets node returns no data or ‘Status=0’ rows missing.”
Cause: Incorrect filter or sheet permissions.
Solution: Verify filter condition in the Sheets node is exact and that the OAuth2 account has read access to the right sheet and range.

Problem: “Replicate API call fails or image not generated.”
Cause: Authentication issues or rate limits.
Solution: Check Replicate API key headers, ensure your account is active, and confirm the prompt text is well-formed JSON and within allowed parameters.

Problem: “Instagram media upload fails or post doesn’t appear.”
Cause: Facebook Graph API version mismatch or incorrect permissions.
Solution: Confirm API version compatibility and that Instagram Business account is linked to the Facebook app with media publishing rights.

Pre-Production Checklist ✅

• Confirm Google Sheets has valid, approved content ideas with Status=0
• Test Google Sheets OAuth2 node can read and update rows
• Validate Google Gemini API keys and test generation of content concepts and captions
• Test Replicate API request with sample prompt and confirm image output
• Verify Facebook Graph API tokens and Instagram Business account connectivity
• Run workflow manually for debugging before activating schedule
• Backup Google Sheet regularly to prevent data loss and allow rollback

Deployment Guide

Once tested, activate your workflow in n8n to run on schedule automatically. Monitor execution logs in n8n for errors or delays.

Enable notifications on failures and periodically review Google Sheets and social accounts to ensure continuous smooth operation.

Optionally, use n8n self-hosted on a cloud VPS for full control and scalability.

FAQs

Q: Can I use this workflow for LinkedIn posts instead of Instagram?
A: Absolutely. The workflow is designed to handle LinkedIn by changing the Platform field in your Google Sheet and ensuring AI prompts align with LinkedIn norms.

Q: Will this consume many AI API credits?
A: Each run will consume credits for each AI call (concept, prompt, caption, and image generation). Monitor your usage and set schedules accordingly.

Q: Is my content secure with cloud AI providers?
A: Data is sent securely via API to trusted providers, but review each service’s privacy policies to ensure compliance with your organizational needs.

Conclusion

You’ve just set up a sophisticated Instagram content automation that not only crafts unique, platform-tailored concepts but also generates compelling AI images and captions, then publishes directly to your account. This reduces the time spent creating posts by hours each week and keeps your social media feed fresh and engaging.

Next, consider expanding your workflow to automate multi-platform posting or add more interactive content formats like carousels or short videos. Happy automating!