n8n OpenAI Assistant Node Setup: Step‑by‑Step Guide

Integrate OpenAI's Assistant API into n8n in five minutes with this exact walkthrough.

What You’ll Need

• n8n instance (self‑hosted or cloud)
• OpenAI API key with Assistant access
• Basic knowledge of JSON

Step 1: Add the OpenAI Node

Open the n8n editor, click + Add node and select OpenAI from the list.

Set the node type to Assistant in the dropdown.

Step 2: Configure Authentication

In the Credentials tab, click New Credentials → OpenAI API.

Paste your API key, enable Assistant Access, and save.

Step 3: Define the Assistant Prompt

In the node’s Prompt field, add the system instruction that will guide the assistant.

{
  "role": "system",
  "content": "You are a helpful assistant that formats responses as HTML for n8n users."
}

Step 4: Map Input Data

Use the Expression editor to feed incoming data into the messages array.

[
  {
    "role": "user",
    "content": {{ $json["question"] }}
  }
]

Step 5: Enable Streaming (Optional)

Toggle Stream to true for real‑time token delivery.

Connect the node’s output to a Set node to extract response.choices[0].message.content.

Quick Reference
Copy this minimal configuration for a functional Assistant node:

{
  "type": "n8n-nodes-base.openAi",
  "parameters": {
    "resource": "assistant",
    "operation": "run",
    "prompt": [{"role":"system","content":"You are a concise assistant."}],
    "messages": [{"role":"user","content":"{{ $json.question }}"}],
    "stream": false
  },
  "credentials": {"openAiApi": {"apiKey": "YOUR_KEY"}}
}

Testing the Workflow

Trigger the workflow with a Webhook node sending {"question":"What is n8n?"}.

The Assistant node returns a formatted HTML answer ready for downstream nodes.

FAQ

Can I use the same node for multiple assistants?

Yes, create separate nodes or dynamically set the assistant_id via an expression.

What limits apply to the Assistant API?

Rate limits follow your OpenAI plan; typical limits are 60 RPM for free tiers.

How do I handle token errors?

Enable the Error Trigger node and inspect error.message for “max tokens” warnings.

Bottom Line

Adding OpenAI’s Assistant to n8n requires only five clear steps: add node, set credentials, craft a system prompt, map input, and optionally enable streaming.

With the provided configuration snippet, you can spin up a production‑ready workflow in under ten minutes.

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