n8n Workflow: OpenAI Chat Completion Automation

How This Blueprint Works

Supercharge your workflows with OpenAI’s GPT and DALL-E models. This pipeline accepts content generation requests via webhook, calls the OpenAI Chat Completion or Image Generation API, and delivers the result wherever you need it.

The Execution Sequence

1. Webhook Node — Accepts POST requests with prompt, model parameters (model, temperature, max_tokens), and optional system_prompt. Supports both JSON and form-data payloads.
2. Prompt Assembler Node — A Code node that structures the OpenAI messages array from the webhook input. Sets system role message, few-shot examples (optional), and the user’s prompt. Validates token count against model limits.
3. OpenAI Call Node — The OpenAI node configured for chat completion. Connects to GPT-4o, GPT-4o-mini, or GPT-4-turbo. Configurable temperature (0.0-2.0), max_tokens, top_p, frequency_penalty, and presence_penalty.
4. Result Handler Node — Sends the model’s response (content + token usage) back to the webhook caller as JSON. Can also store results in a database or pass to downstream workflow nodes.
5. Token Tracker Node — A Code node that calculates cost per call using OpenAI’s per-model pricing. Logs each call’s prompt_tokens, completion_tokens, model, and estimated cost to a Google Sheet for billing.

FAQ

What OpenAI models does this workflow support?

All chat-compatible models: GPT-4o, GPT-4o-mini, GPT-4-turbo, GPT-4, GPT-3.5-turbo. For image generation, the workflow supports DALL-E 3 with configurable size (1024x1024, 1792x1024) and quality (standard, hd).

How can I manage OpenAI API costs?

The Token Tracker node logs every call to a Google Sheet. Set monthly budget alerts by adding a Code node that sums costs and sends a warning if a threshold is exceeded.

Can I chain multiple AI calls in one workflow?

Yes. Connect the output of one OpenAI node to another. A common pattern: first call generates a blog post outline, second call expands each section, third call generates an SEO meta description.

The JSON Blueprint Structure

{
  "name": "OpenAI Content Pipeline",
  "nodes": [
    { "name": "Webhook", "type": "n8n-nodes-base.webhook", "position": [250, 300] },
    { "name": "Prompt Builder", "type": "n8n-nodes-base.code", "position": [450, 300] },
    { "name": "OpenAI Chat", "type": "n8n-nodes-base.openAi", "position": [650, 300] },
    { "name": "Cost Logger", "type": "n8n-nodes-base.googleSheets", "position": [850, 300] }
  ]
}

What You Get Inside Your SynthOperator System

This workflow is one of 27,400+ blueprints included in the n8n Business Automation OS ($17, one-time). When you deploy the complete system, you get:

• 27,400+ pre-built workflow JSON files across every business domain
• 15 elite AI agents integrated into your automation pipelines
• Lifetime updates, offline operation, and zero recurring fees

**Deploy your complete automation infrastructure today.