Connecting n8n Workflows to OpenWebUI via MCP

This guide walks you through exposing n8n workflows as tools in OpenWebUI using the Model Context Protocol (MCP).

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Prerequisites

• Access to your n8n instance (version 1.123.18 or later)

• Admin rights in n8n

• Access to OpenWebUI with admin or tool management permissions

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Step 1: Enable MCP Access in n8n

1. In your n8n instance, click the three dots (...) next to your username in the bottom-left corner.

2. Select Settings from the popup menu.

3. In the Settings sidebar, scroll down and click MCP Access.

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Step 2: Configure the MCP Server

On the MCP Access settings page:

1. Enable the Enable MCP toggle to activate MCP access for your n8n instance.

2. Under How to connect, choose your preferred authentication method:

   • OAuth – recommended for user-delegated access

   • Access Token – simpler option for server-to-server connections

3. Copy the Server URL shown in the field (e.g. https://n8n.yourdomain.com/mcp-server/...). You will need this URL when configuring OpenWebUI.

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Step 3: Add n8n as an External Tool in OpenWebUI

1. In OpenWebUI, go to Settings (top navigation) and select the Functions or Instellingen tab.

2. Click External Tools in the left sidebar.

3. Click the + button to add a new tool server.

4. Enter a name for the connection (e.g. GLBNXT N8N) and paste the Server URL you copied from n8n.

5. Configure the authentication to match what you selected in Step 2 (OAuth or Access Token).

6. Save the configuration.

Once connected, your n8n server will appear in the External Tools list alongside any other configured tool servers.

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Step 4: Enable MCP Access on Individual Workflows

MCP access must be enabled per individual n8n workflow. For each workflow you want to expose as a tool:

1. Go to your Workflows overview in n8n.

2. Find the workflow you want to expose, click the three-dot menu (⋮) on the right.

3. Select Enable MCP access from the dropdown menu.

Only workflows with MCP access enabled will be available as tools in OpenWebUI.

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Step 5: Use n8n Workflows as Tools in Chat

After the connection is established, your enabled n8n workflows will be available as callable tools during chat sessions in OpenWebUI. The AI model can invoke these workflows automatically based on context, or you can trigger them explicitly through the tool interface.

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Tips

• If a workflow does not appear as a tool, verify that Enable MCP access has been toggled on for that specific workflow in n8n.

• Use descriptive workflow names in n8n so they are easy to identify and invoke in OpenWebUI.

• For production setups, OAuth is preferred over Access Token for better security and auditability.