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Beginner AI Dataset Generator using OpenAI + LangChain in n8n

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Created by: Robert Breen || rbreen

Robert Breen

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Last update a day ago

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This n8n workflow dynamically generates a realistic sample dataset based on a single topic you provide. It uses OpenAI (via LangChain) and n8n’s built-in nodes to:

  1. Generate structured JSON data for 5 columns with 3–5 values each
  2. Flatten that data into a single text blob
  3. Infer meaningful column names via a second AI call
  4. Pivot, split, merge, and rename columns automatically
  5. Output a clean, labeled dataset ready for export or further processing

⚙️ Prerequisites

  1. OpenAI API Key

  2. LangChain nodes enabled in your n8n instance

🥇 Step 1: Set Up OpenAI Credential

  1. Go to OpenAI API Keys
  2. Create and copy your key
  3. In n8n: Credentials → New → OpenAI API → paste key as “OpenAi account”

🥈 Step 2: Manual Trigger

  • Add Manual Trigger to start the workflow

🥉 Step 3: Set Topic

  • Add a Set node named Set Topic to Search
  • Field: Topic = n8n use cases (or any topic you choose)

✨ Step 4: Generate Structured Data

  • LangChain Agent node Generate Random Data
  • Connect to OpenAI Chat Model1 and Tool: Inject Creativity1
  • System prompt: instruct AI to output 5 columns of realistic values in JSON

🔧 Step 5: Parse AI Output

  • Structured Output Parser to validate JSON

🔄 Step 6: Flatten Data

  • Code node Outpt all Data to One Field
  • Joins all values into a comma-separated string for column naming

🧠 Step 7: Generate Column Names

  • LangChain Agent Generate Column Names
  • Connect to OpenAI Chat Model2
  • Prompt: infer 5 column names from the string

🔢 Step 8: Pivot Names Row

  • Code node Pivot Column Names transforms array into { column1: name1, … }

🪓 Step 9: Split Columns

  • 5 SplitOut nodes to break each array back into rows per column

🔗 Step 10: Merge Rows

  • Merge node Merge Columns together using combineByPosition

🏷️ Step 11: Rename Columns

  • Set node Rename Columns assigns the AI-generated names to each column

🔗 Step 12: Final Output

  • Merge Append Column Names combines data and header row

🏁 Done! You now have a fully AI-driven, labeled dataset generated from a single topic—no external services needed. Easily extend by adding a Google Sheets or HTTP node to export.

📬 Need Help or Want to Customize This?

📧 [email protected]
🔗 LinkedIn