Back to Catalog

Beginner AI dataset generator using OpenAI + LangChain in n8n

Robert BreenRobert Breen
1614 views
2/3/2026
Official Page

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

    • Visit: https://platform.openai.com/account/api-keys
    • Create a new key
    • In n8n: Credentials → New → OpenAI API, paste key, name it “OpenAi account”
  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?

📧 robert@ynteractive.com
🔗 LinkedIn

n8n Beginner AI Dataset Generator using OpenAI and Langchain

This n8n workflow demonstrates a foundational setup for generating structured AI datasets using OpenAI's chat models and Langchain's capabilities within n8n. It provides a starting point for creating diverse data points based on a user-defined prompt.

What it does

This workflow takes a user-defined prompt, processes it through an AI agent powered by OpenAI, and then structures the output into a usable dataset format.

  1. Manual Trigger: Initiates the workflow when manually executed.
  2. Edit Fields (Set): Defines the initial prompt that will be fed to the AI model. This is where you specify what kind of data you want to generate.
  3. AI Agent (Langchain): Acts as the orchestrator, taking the prompt and deciding which tools to use to fulfill the request. In this workflow, it uses an internal "Think" tool.
  4. Think Tool (Langchain): A placeholder tool within the Langchain agent that can be expanded to perform specific actions or reasoning steps.
  5. OpenAI Chat Model (Langchain): The core AI model that generates responses based on the prompt and the agent's reasoning.
  6. Structured Output Parser (Langchain): Takes the raw AI output and attempts to parse it into a structured format (e.g., JSON), making it easier to consume and use as a dataset.
  7. Split Out: If the structured output contains an array of items, this node splits them into individual items, allowing for further processing of each data point.
  8. Merge: Combines data from different branches of the workflow, though in this basic setup, it primarily serves to consolidate the final output.
  9. Code: A custom JavaScript code block that can be used for advanced data manipulation or logging if needed. (Currently empty, ready for customization).

Prerequisites/Requirements

  • n8n Instance: A running n8n instance (cloud or self-hosted).
  • OpenAI API Key: An API key for OpenAI to use their chat models. This will need to be configured as a credential in n8n for the "OpenAI Chat Model" node.
  • Langchain Nodes: Ensure the @n8n/n8n-nodes-langchain package is installed in your n8n instance.

Setup/Usage

  1. Import the workflow: Download the JSON provided and import it into your n8n instance.
  2. Configure Credentials:
    • Locate the "OpenAI Chat Model" node.
    • Click on the "Credentials" field and select or create a new "OpenAI API" credential.
    • Enter your OpenAI API Key when prompted.
  3. Define your prompt:
    • Locate the "Edit Fields (Set)" node.
    • Modify the prompt field to define the type of dataset you want to generate (e.g., "Generate 5 examples of product descriptions for a new line of eco-friendly water bottles, including product name, features, and a short marketing slogan, in JSON format.").
  4. Execute the workflow: Click the "Execute Workflow" button in the "Manual Trigger" node or activate the workflow to run it.
  5. Review Output: Inspect the output of the "Structured Output Parser" and "Split Out" nodes to see your generated dataset. The "Merge" and "Code" nodes will contain the final processed data.

This workflow provides a flexible foundation for generating various AI-powered datasets. You can extend it by adding more tools to the AI agent, integrating with databases or storage services, or refining the output parsing logic.

Related Templates

Automate Dutch Public Procurement Data Collection with TenderNed

TenderNed Public Procurement What This Workflow Does This workflow automates the collection of public procurement data from TenderNed (the official Dutch tender platform). It: Fetches the latest tender publications from the TenderNed API Retrieves detailed information in both XML and JSON formats for each tender Parses and extracts key information like organization names, titles, descriptions, and reference numbers Filters results based on your custom criteria Stores the data in a database for easy querying and analysis Setup Instructions This template comes with sticky notes providing step-by-step instructions in Dutch and various query options you can customize. Prerequisites TenderNed API Access - Register at TenderNed for API credentials Configuration Steps Set up TenderNed credentials: Add HTTP Basic Auth credentials with your TenderNed API username and password Apply these credentials to the three HTTP Request nodes: "Tenderned Publicaties" "Haal XML Details" "Haal JSON Details" Customize filters: Modify the "Filter op ..." node to match your specific requirements Examples: specific organizations, contract values, regions, etc. How It Works Step 1: Trigger The workflow can be triggered either manually for testing or automatically on a daily schedule. Step 2: Fetch Publications Makes an API call to TenderNed to retrieve a list of recent publications (up to 100 per request). Step 3: Process & Split Extracts the tender array from the response and splits it into individual items for processing. Step 4: Fetch Details For each tender, the workflow makes two parallel API calls: XML endpoint - Retrieves the complete tender documentation in XML format JSON endpoint - Fetches metadata including reference numbers and keywords Step 5: Parse & Merge Parses the XML data and merges it with the JSON metadata and batch information into a single data structure. Step 6: Extract Fields Maps the raw API data to clean, structured fields including: Publication ID and date Organization name Tender title and description Reference numbers (kenmerk, TED number) Step 7: Filter Applies your custom filter criteria to focus on relevant tenders only. Step 8: Store Inserts the processed data into your database for storage and future analysis. Customization Tips Modify API Parameters In the "Tenderned Publicaties" node, you can adjust: offset: Starting position for pagination size: Number of results per request (max 100) Add query parameters for date ranges, status filters, etc. Add More Fields Extend the "Splits Alle Velden" node to extract additional fields from the XML/JSON data, such as: Contract value estimates Deadline dates CPV codes (procurement classification) Contact information Integrate Notifications Add a Slack, Email, or Discord node after the filter to get notified about new matching tenders. Incremental Updates Modify the workflow to only fetch new tenders by: Storing the last execution timestamp Adding date filters to the API query Only processing publications newer than the last run Troubleshooting No data returned? Verify your TenderNed API credentials are correct Check that you have setup youre filter proper Need help setting this up or interested in a complete tender analysis solution? Get in touch 🔗 LinkedIn – Wessel Bulte

Wessel BulteBy Wessel Bulte
247

AI-powered code review with linting, red-marked corrections in Google Sheets & Slack

Advanced Code Review Automation (AI + Lint + Slack) Who’s it for For software engineers, QA teams, and tech leads who want to automate intelligent code reviews with both AI-driven suggestions and rule-based linting — all managed in Google Sheets with instant Slack summaries. How it works This workflow performs a two-layer review system: Lint Check: Runs a lightweight static analysis to find common issues (e.g., use of var, console.log, unbalanced braces). AI Review: Sends valid code to Gemini AI, which provides human-like review feedback with severity classification (Critical, Major, Minor) and visual highlights (red/orange tags). Formatter: Combines lint and AI results, calculating an overall score (0–10). Aggregator: Summarizes results for quick comparison. Google Sheets Writer: Appends results to your review log. Slack Notification: Posts a concise summary (e.g., number of issues and average score) to your team’s channel. How to set up Connect Google Sheets and Slack credentials in n8n. Replace placeholders (<YOURSPREADSHEETID>, <YOURSHEETGIDORNAME>, <YOURSLACKCHANNEL_ID>). Adjust the AI review prompt or lint rules as needed. Activate the workflow — reviews will start automatically whenever new code is added to the sheet. Requirements Google Sheets and Slack integrations enabled A configured AI node (Gemini, OpenAI, or compatible) Proper permissions to write to your target Google Sheet How to customize Add more linting rules (naming conventions, spacing, forbidden APIs) Extend the AI prompt for project-specific guidelines Customize the Slack message formatting Export analytics to a dashboard (e.g., Notion or Data Studio) Why it’s valuable This workflow brings realistic, team-oriented AI-assisted code review to n8n — combining the speed of automated linting with the nuance of human-style feedback. It saves time, improves code quality, and keeps your team’s review history transparent and centralized.

higashiyama By higashiyama
90

🎓 How to transform unstructured email data into structured format with AI agent

This workflow automates the process of extracting structured, usable information from unstructured email messages across multiple platforms. It connects directly to Gmail, Outlook, and IMAP accounts, retrieves incoming emails, and sends their content to an AI-powered parsing agent built on OpenAI GPT models. The AI agent analyzes each email, identifies relevant details, and returns a clean JSON structure containing key fields: From – sender’s email address To – recipient’s email address Subject – email subject line Summary – short AI-generated summary of the email body The extracted information is then automatically inserted into an n8n Data Table, creating a structured database of email metadata and summaries ready for indexing, reporting, or integration with other tools. --- Key Benefits ✅ Full Automation: Eliminates manual reading and data entry from incoming emails. ✅ Multi-Source Integration: Handles data from different email providers seamlessly. ✅ AI-Driven Accuracy: Uses advanced language models to interpret complex or unformatted content. ✅ Structured Storage: Creates a standardized, query-ready dataset from previously unstructured text. ✅ Time Efficiency: Processes emails in real time, improving productivity and response speed. *✅ Scalability: Easily extendable to handle additional sources or extract more data fields. --- How it works This workflow automates the transformation of unstructured email data into a structured, queryable format. It operates through a series of connected steps: Email Triggering: The workflow is initiated by one of three different email triggers (Gmail, Microsoft Outlook, or a generic IMAP account), which constantly monitor for new incoming emails. AI-Powered Parsing & Structuring: When a new email is detected, its raw, unstructured content is passed to a central "Parsing Agent." This agent uses a specified OpenAI language model to intelligently analyze the email text. Data Extraction & Standardization: Following a predefined system prompt, the AI agent extracts key information from the email, such as the sender, recipient, subject, and a generated summary. It then forces the output into a strict JSON structure using a "Structured Output Parser" node, ensuring data consistency. Data Storage: Finally, the clean, structured data (the from, to, subject, and summarize fields) is inserted as a new row into a specified n8n Data Table, creating a searchable and reportable database of email information. --- Set up steps To implement this workflow, follow these configuration steps: Prepare the Data Table: Create a new Data Table within n8n. Define the columns with the following names and string type: From, To, Subject, and Summary. Configure Email Credentials: Set up the credential connections for the email services you wish to use (Gmail OAuth2, Microsoft Outlook OAuth2, and/or IMAP). Ensure the accounts have the necessary permissions to read emails. Configure AI Model Credentials: Set up the OpenAI API credential with a valid API key. The workflow is configured to use the model, but this can be changed in the respective nodes if needed. Connect the Nodes: The workflow canvas is already correctly wired. Visually confirm that the email triggers are connected to the "Parsing Agent," which is connected to the "Insert row" (Data Table) node. Also, ensure the "OpenAI Chat Model" and "Structured Output Parser" are connected to the "Parsing Agent" as its AI model and output parser, respectively. Activate the Workflow: Save the workflow and toggle the "Active" switch to ON. The triggers will begin polling for new emails according to their schedule (e.g., every minute), and the automation will start processing incoming messages. --- Need help customizing? Contact me for consulting and support or add me on Linkedin.

DavideBy Davide
1616