Auto-Caption & Post Videos to Instagram & TikTok with Submagic, Postiz & OpenAI

🎥 Auto-Caption & Autopost Videos to Instagram & TikTok

Description Automate your short-form content pipeline! This workflow takes any video uploaded to a specific Google Drive folder, generates engaging captions with Submagic, and then auto-posts the finished video (with AI-generated captions) directly to Instagram or TikTok via Postiz. Captions are further refined with OpenAI for brand-ready social text. Finally, each published video is logged into a Google Sheet for tracking.

👉 Watch step-by-step build of this workflow on: www.youtube.com/@automatewithmarc

How It Works

Google Drive Trigger – Detects new video uploads.

Submagic API – Adds styled captions automatically.

Wait + Poll – Monitors job status until the captioned video is ready.

Download Video – Retrieves the finished captioned video.

Upload to Postiz – Sends the file to Postiz for multi-platform posting.

Caption Agent (OpenAI) – Generates optimized Instagram/TikTok captions.

Post to Instagram/TikTok – Publishes the video with caption.

Update Log – Saves video details, captions, and status into Google Sheets.

Why You’ll Love It

⚡ Hands-off publishing — videos go from raw to posted automatically.

📝 AI captions + Submagic styling — engaging text and visual consistency.

📊 Content tracking — every post logged in Google Sheets.

🎯 Perfect for Reels & TikToks — optimized for fast workflows and social reach.

Requirements

Google Drive account Submagic API key Postiz account (for IG/TikTok posting) OpenAI API key (for caption generation) Google Sheets account