If you’re exploring n8n integrations for AI automation inside your workflows, especially for tasks like content generation, CRM enrichment, or HubSpot workflow automation, you’ll eventually need to connect OpenAI. But many users get stuck on one simple issue: how to add OpenAI API key to n8n node without running into authentication errors.
This guide gives you a clear, practical, real-world explanation based on years of implementing automation solutions for businesses.
Why Adding the OpenAI API Key Correctly Matters
Most errors people face when working with OpenAI in n8n come from a very small part of the setup—the credential configuration.
If this step isn’t correct, you’ll face issues like:
Let’s walk through the right way to set it up.
How n8n Connects to OpenAI
Before adding the key, it helps to understand how n8n handles integration:
-
n8n stores API keys securely inside Credentials
-
Every OpenAI node pulls from these credentials
-
If the credential fails, the entire workflow fails
-
You only need to add the key once and use it in multiple nodes
How to Add OpenAI API Key to n8n Node (Step-by-Step)
1. Get Your OpenAI API Key
Log in to the OpenAI platform and generate your API key under your account settings.
The most common mistake here is using a key from an account that does not have billing enabled. Even with correct credentials, OpenAI may reject requests if billing isn’t active.
2. Open n8n and Navigate to Credentials
In your n8n dashboard:
3. Paste Your API Key
Add the key exactly as provided by OpenAI.
Small formatting issues (like invisible spaces) can cause the node to reject the key.
4. Save and Assign the Credential to Your OpenAI Node
In your automation:
At this point, n8n and OpenAI are successfully connected.
Real-World Problems Users Face (With Solutions)
Scenario 1: “My API key is correct, but n8n says it’s invalid.”
A marketing manager was trying to generate product descriptions automatically, but kept receiving an authentication error. The issue wasn’t the key—it was that their OpenAI billing setup wasn’t active. Once updated, everything worked instantly.
Scenario 2: “The credential doesn’t appear in the dropdown list.”
A business owner added the key correctly but couldn’t find it inside the node.
The cause? An outdated n8n version. After upgrading, the credential appeared.
Scenario 3: “The workflow works once and then breaks.”
A sales operations team used OpenAI to clean up notes and send summaries to HubSpot.
Their setup failed during busy hours due to exceeding rate limits.
Adding pauses and spreading automation tasks across intervals fixed the issue.
How to Add OpenAI API Key to n8n Node API
If you are using the HTTP Request node instead of the OpenAI node, you can still use your credential by selecting it under the authentication settings.
This is helpful when you want more control over:
How to Add OpenAI API Key to n8n Node for Free
You can connect the API key to n8n for free. What determines cost is your OpenAI usage.
You can use OpenAI for free if:
-
You still have free trial credits
-
You use lower-cost models
-
You run automations at low frequency
There is no n8n-specific charge for adding the API key.
How to Add OpenAI API Key to n8n Node Using Python
Many advanced users extend n8n power using Python inside the Code node. While we removed the Python examples, the key takeaway is:
You can reference your stored OpenAI credential inside Python-based steps without exposing your API key.
How to Add OpenAI API Key to n8n Node in Python
Inside Python code within n8n, you simply call your saved credential instead of typing the key directly. This keeps your automations secure and prevents accidental exposure.
Relevant Guide
What Is n8n and How to Use It: A Complete Beginner’s Guide
Does Wix Connect to Hubspot – Find 5 Easy Methods
Can You Pull in HubSpot Standard Object in Automated Email – Beginners Guide
How Can You Associate Products with Companies in HubSpot – Guide for Marketers
HubSpot Sales Hub Implementation
HubSpot Marketing Hub Implementation
HubSpot WooCommerce Integration
Conclusion
Understanding how to add OpenAI API key to n8n node sets the foundation for powerful automations across customer service, sales operations, marketing content, CRM enrichment, and internal workflow enhancements.
When the key is added correctly, n8n can interact with OpenAI consistently, helping teams build smarter, automated processes that save time and reduce manual work.
If you want help building intelligent workflows or integrating n8n with HubSpot and other business systems, Mpire Solutions offers expert guidance and implementation support.
FAQs
Go to the Credentials section, add OpenAI, paste your key, and select it in your OpenAI node.
It may be expired, incorrectly formatted, disabled due to billing, or pasted with extra spaces.
Install the official OpenAI SDK or use axios/fetch to call the API, then configure your API key via environment variables and send requests to OpenAI’s endpoints from your Node.js application.
Sign in to your OpenAI account, go to the API keys section, generate a new secret key, then copy and store it securely in your app or tool (for example, as an environment variable).
In n8n, use HTTP Request or specific integration nodes, configure the endpoint, method, headers (including API key or auth), test the call, and then plug that node into your workflow.
HubSpot Consulting Needs
