Social Media Auto-Poster (Google Sheets → Twitter & Instagram)

This workflow automatically:

1. Pulls rows marked as Pending from a Google Sheet.
2. Generates a formatted Instagram caption and HTML preview.
3. Converts the HTML into an image via HCTI.io.
4. Posts the content:
   • As a tweet (text only) to Twitter (X).
   • As a post (image + caption) to Instagram via the Facebook Graph API.
5. Marks the row in Google Sheets as Posted with a timestamp.

It runs every 5 hours (configurable via the Schedule Trigger).

Requirements

• Google Sheets API Credentials connected in n8n.
• HCTI.io account (HTML → Image API).
• Twitter (X) OAuth1 credentials.
• Facebook/Instagram Graph API access token (for the business account/page).
• A Google Sheet with at least these columns:
  • RowID
  • Caption
  • Desc
  • Hashtags
  • Status

Set Status to Pending for any row you want posted.

Setup

1. Import the JSON workflow (My_workflow.json) into your n8n instance.
2. Link all credentials (replace placeholders with your own API keys and tokens).
3. Update the Google Sheet ID and Sheet Name inside the Get row(s) in sheet and Update Status Posted nodes.
4. (Optional) Adjust the posting interval in the Schedule Trigger node.

How It Works

1. Trigger: Runs every 5 hours.
2. Fetch Rows: Reads Google Sheets for rows with Status = Pending.
3. Caption Generation: Combines Desc + Hashtags into final_caption.
4. HTML → Image: Converts caption to a styled 1080x1080 post.
5. Social Posting:
   • Posts the caption to Twitter (text only).
   • Uploads the image + caption to Instagram.
6. Update Status: Marks the row as Posted on [timestamp].

Notes

• Facebook/Instagram tokens expire; refresh or use long-lived tokens.
• HCTI.io may require a paid plan for high volumes.
• Works best with a business Instagram account linked to a Facebook Page.

License

This workflow can be reused and adapted freely under the MIT license.