Auto-Caption & Multi-Platform Video Posting with Submagic, Postiz & AI - n8n Workflow

Content creators and marketers who manage high volumes of short-form video (Reels, TikToks).
Agencies looking to streamline client video production and posting.
Technical users seeking an advanced example of a production-ready n8n workflow.
Anyone interested in leveraging AI (OpenAI) and specialized video tools (Submagic, Postiz) within an n8n workflow.

Managing short-form video content across multiple platforms requires speed, consistency, and efficient captioning. This comprehensive n8n workflow solves the tedious manual process of downloading, captioning, writing social copy, and uploading. It uses the Google Drive n8n trigger to initiate the sequence automatically when a new video file is added to a designated folder.

The core value provided by this n8n template lies in its multi-stage automation: it leverages Submagic for high-quality, professional video captions (like the popular 'Hormozi 2' style) and then employs an OpenAI LangChain Agent within the n8n workflow to craft highly optimized, brand-specific social media captions. The final step ensures the content is posted instantly to platforms like Instagram using the Postiz API. This robust n8n workflow guarantees hands-off publishing and provides a centralized log in Google Sheets, making this one of the most effective n8n templates for video distribution.

This automation begins immediately upon a new video file being created in a specific Google Drive folder, thanks to the Google Drive Trigger n8n node.

1. Video Submission and Captioning: The n8n workflow immediately sends the video's public link to the Submagic API (Post to Submagic n8n node) to initiate the automated captioning process, applying the 'Hormozi 2' template.


2. Polling for Completion: Because captioning takes time, the n8n workflow uses a delay (Wait 15 Secs1) followed by polling (Get Captioned Video from Submagic) and an If n8n node to check the processing status. If the status is 'completed', the workflow proceeds; otherwise, it waits again (Wait 15 Secs) and polls again.


3. Downloading & Uploading: Once ready, the captioned video is downloaded (Download Captioned Video) and then uploaded to the Postiz service (Upload to Postiz), preparing it for multi-platform distribution. This sequence is crucial for ensuring the social posting service has the final, captioned asset.


4. Logging and Preparation: The workflow logs the transaction status into Google Sheets using the Update Log n8n node.


5. AI Caption Generation: The n8n workflow retrieves the necessary details from the sheet and feeds the 'Image Prompt' into the Caption Agent. This specialized n8n node, utilizing the OpenAI Chat Model (GPT-5 is specified), follows precise guidelines to generate short, engaging social media copy tailored for the specified brand (Larrydoodle).


6. Final Posting: The last step uses the Post to Instagram n8n node (an HTTP Request to Postiz) to publish the video immediately, combining the uploaded video ID from Postiz and the AI-generated caption from the Caption Agent n8n node.

To deploy this comprehensive n8n workflow template, follow these steps:

1. Import: Copy the provided JSON data and paste it into your n8n canvas using the 'New' -> 'Import from JSON' option.


2. Credentials: Set up the required credentials for each service:

1. Configuration: Update placeholder values in the Google Drive Trigger (folder ID) and Google Sheets n8n nodes (Sheet ID/Name) to match your setup.


2. Activation: Once all credentials and parameters are set, activate the n8n trigger to enable the automatic execution of this robust n8n workflow.

Google Drive Trigger: This n8n trigger node starts the entire n8n workflow. It is configured to monitor a specific Google Drive folder for the 'fileCreated' event.
Post to Submagic (HTTP Request): Sends the video URL received from the Google Drive n8n trigger to the Submagic API for automatic caption generation. Key configurations include setting the method to POST, and specifying the videoUrl and templateName ('Hormozi 2').
Wait 15 Secs1 / Wait 15 Secs (Wait): Essential flow control n8n node used to pause execution, allowing Submagic time to process the video before the n8n workflow attempts to check the status.
If (If): A core logic n8n node that checks the status returned by the Submagic API. It branches the n8n workflow, continuing only if the status equals 'completed'.
Download Captioned Video (HTTP Request): Retrieves the final, captioned video file from Submagic using the generated downloadUrl.
Upload to Postiz (HTTP Request): Sends the downloaded video binary data to Postiz using a multipart-form-data POST request. This step provides the necessary file IDs for the final posting n8n node.
Update Log (Google Sheets): Logs the initial video details (Prompt, URL) into the specified Google Sheets document. This is a crucial data tracking n8n node.
Get row(s) in sheet (Google Sheets): Reads data from the logging sheet, typically to retrieve the prompt or description needed for the AI.
Caption Agent (LangChain Agent): This advanced n8n node uses the OpenAI Chat Model to generate the final, high-quality social media caption. It is configured with a detailed system prompt defining tone, output rules, and CTAs, ensuring brand consistency across the n8n workflow.
Post to Instagram (HTTP Request): The final action n8n node. It sends a structured JSON payload to the Postiz API, containing the video file ID and the AI-generated caption, triggering the immediate publication of the content to Instagram. This effectively completes the automated n8n workflow.