Automate GPT-4o fine-tuning with Google Sheets or Airtable data

Who is this for? Anyone curating before/after text examples in a spreadsheet and wanting a push-button path to a fine-tuned GPT model—without touching curl. Works with Google Sheets or Airtable. --- What problem does it solve? Manually downloading CSVs, converting to JSONL, uploading, and polling OpenAI is a slog. This flow automates the whole loop: grab examples flagged Ready, build the JSONL file, start the fine-tune, then log the resulting model ID back to a registry sheet/table for reuse. --- How it works | # | Node | Purpose | |---|------|---------| | 1 | Schedule Trigger | Runs weekly by default (change as needed). | | 2a | Get Examples from Sheet | Pulls rows where Ready = TRUE from your Google Sheet. Uses the JSONL-Template Sheet as the expected column layout. | | 2b | Get Examples from Airtable (disabled) | Alternate source for Airtable users. | | 3 | Create JSONL File (Code) | Converts each example to chat-format JSONL and splits into train.jsonl / val.jsonl (80/20). | | 4 | Upload JSONL | Uploads the training file to OpenAI (purpose: fine-tune). | | 5 | Begin Fine-Tune | Starts a fine-tune job on gpt-4o (editable). | | 6 | Wait → Check Job → IF | Polls every minute until status = succeeded. | | 7a | Write Model to Sheet | Appends the new model ID + meta to your Model Registry sheet. | | 7b | Write Model to Airtable (disabled) | Equivalent logging step for Airtable. | --- Setup steps 1. Import & connect credentials Import the JSON flow into n8n. Add your OpenAI API key. Google Sheets: create an OAuth2 credential and link it to both Sheets nodes. Airtable (optional): create a Personal Access Token and attach it to the Airtable nodes. 2. Copy the template sheet Duplicate the JSONL-Template Sheet linked above into your own Drive. Required columns (exact names): | systemPrompt | userPrompt | assistantResponse | Ready | Tick Ready = TRUE for rows you want to include. 3. Create the registry sheet/table Google Sheet (or Airtable table) named Model Registry with columns: Model ID, Training Examples, Epochs, Batch Size, Learning Rate, Finished At. 4. Tweak model & schedule Change the base model in Begin Fine-Tune if desired. Adjust the Schedule Trigger for daily / on-demand runs. 5. Test it Mark a few examples Ready = TRUE. Run the flow manually. Check OpenAI for the new fine-tune job and confirm the model ID is logged in your registry. --- Resources n8n Docs – < OpenAI Fine-Tuning – < Google Sheets API – < Airtable API – < --- Extending the flow Webhook trigger – swap the schedule for a webhook to train on demand. Multi-source merge – enable both Sheets and Airtable nodes to combine datasets. Auto-deploy – save the new model name to an env-var or Secrets Manager for downstream generation workflows.