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How to Modify the n8n Tool

Automation has become an essential part of how businesses and individuals manage their workflows. The ability to connect apps, services, and data without manual intervention saves time and reduces errors. Among the many tools available today, n8n stands out as a flexible, open-source workflow automation platform. It allows users to create complex automation “workflows” by visually connecting “nodes” that represent different apps or functions.

However, no tool is perfect out-of-the-box. Sometimes, you might need to extend n8n beyond its default capabilities — adding support for internal APIs, custom business logic, or personalized UI tweaks. This is where modifying n8n comes into play.

This blog post will walk you through the essentials of customizing n8n — from understanding its architecture, setting up your development environment, to modifying backend nodes, tweaking the frontend UI, testing, and deploying your customized version. Whether you are a developer looking to build new nodes or an automation enthusiast eager to tweak the interface, this guide is designed to help you take full control of n8n’s potential.

Understanding n8n’s Architecture

Before jumping into code, it’s crucial to understand how n8n is built. This foundational knowledge helps you make modifications safely and effectively.

n8n’s architecture consists primarily of two parts:

Backend — The Engine of Automation

  • Written in Node.js, the backend executes workflows, manages nodes, stores credentials, and handles communication with external services.
  • Nodes — the building blocks of workflows — contain the logic for individual tasks (like sending an email or fetching data).
  • Credentials securely store sensitive data such as API keys, OAuth tokens, or passwords.
  • The backend exposes a REST API that the frontend uses to interact with workflows and nodes.

Frontend — The Visual Editor

  • Built using Vue.js, the frontend provides a graphical interface where users design workflows by dragging and dropping nodes.
  • It manages user interaction, node configuration, and visual representation of workflows.
  • The UI calls backend endpoints to fetch node data, execute workflows, and save changes.

Workflows, Nodes, and Credentials: How They Interact

  • Workflows are sets of connected nodes that run in sequence or based on triggers.
  • Each node performs a specific function — like transforming data, connecting to an API, or sending a notification.
  • Credentials are tied to nodes but managed separately for security reasons.

Understanding this separation clarifies what parts you need to modify when customizing n8n — for example, writing new nodes means working mostly with the backend, while changing how the editor looks involves frontend work.

Setting Up Your Development Environment

Before you can start modifying n8n, you’ll need to prepare a local development environment. This allows you to write code, run tests, and see your changes in real-time without affecting a live system.

Step 1: Clone the n8n GitHub Repository

Start by cloning the official n8n repository from GitHub to your local machine:

Bash
git clone https://github.com/n8n-io/n8n.git

This will download all the source code you need to build and modify the tool.

Step 2: Install Dependencies

Next, navigate into the n8n folder and install all required dependencies with:

Bash
cd n8n
npm install

n8n’s codebase uses a monorepo structure, meaning it contains multiple packages within one repository — for example, backend, frontend, and nodes. npm install will install dependencies for all parts.

If you prefer faster installs, you can use pnpm:

Bash
pnpm install

Step 3: Running n8n Locally

To start n8n in development mode, run:

Bash
npm run dev

This command builds and runs both backend and frontend servers, enabling you to access the editor in your browser at http://localhost:5678.

You’ll be able to create and test workflows, and any changes you make to the code will reload automatically.

Helpful Tools and Tips

  • Docker: For containerized environments, you can build a Docker image from your modified code and test it in isolation.
  • Visual Studio Code (VSCode): A powerful editor with built-in debugging tools, perfect for Node.js and Vue.js.
  • Debugging: Use Chrome DevTools or VSCode breakpoints to step through your code during execution.
  • Git: Maintain branches for your customizations to keep track of your work and easily merge upstream updates.

Modifying the Backend

Most customizations to n8n’s behavior happen on the backend side. This is where nodes live, workflows run, and the core logic operates.

a. Adding a Custom Node

One of the most common modifications is creating a new node to connect to a service or perform custom logic not supported by default.

Step 1: Locate the nodes folder

Node code lives in the packages/nodes-base/nodes directory. Each node typically has its own .ts file.

Step 2: Create a new node file

Create a file called HelloWorld.node.ts to keep things simple.

Step 3: Write your node logic

At a minimum, a node needs:

  • A description describing the node’s name, inputs, outputs, and parameters.
  • An execute() method containing the code to run when the node executes.

Example code for a “Hello World” node:

TypeScript
import { INodeExecutionData, INodeType, INodeTypeDescription } 
from 'n8n-workflow';

export class HelloWorld implements INodeType {
    description: INodeTypeDescription = {
        displayName: 'Hello World',
        name: 'helloWorld',
        icon: 'file:helloworld.svg',
        group: ['transform'],
        version: 1,
        description: 'Returns a greeting message',
        defaults: {
            name: 'Hello World',
        },
        inputs: ['main'],
        outputs: ['main'],
        properties: [],
    };

    async execute(this: INodeType): Promise<INodeExecutionData[][]> {
        const returnData = [{ json: { message: 'Hello, World!' } }];
        return [returnData];
    }
}

Step 4: Add your node to the index

Add your new node class to the export list in packages/nodes-base/nodes/index.ts so it gets recognized by n8n.

Step 5: Test your node

Restart your local n8n server (npm run dev), open the editor, and find your “Hello World” node under the transform category. Run it and check the output.

Tips for Building Custom Nodes

  • Use existing nodes as references.
  • Keep your logic simple and focused.
  • Handle errors gracefully — returning informative messages to the user.
  • Add configuration parameters if your node needs input.
  • Document your node’s purpose and usage clearly.

b. Extending Credentials or Adding a New Credential Type

If your workflows need to connect to private APIs or services that require authentication, you may need to create custom credentials.

Step 1: Locate credentials folder

Credentials live in packages/nodes-base/credentials.

Step 2: Create a new credential file

Example: MyApiCredential.
credentials.ts.

Step 3: Define credential properties

You specify what data is needed — such as API keys, usernames, passwords, OAuth2 info — and add validation rules.

Example snippet:

TypeScript
import { ICredentialType, INodeProperties } from 'n8n-workflow';

export class MyApiCredential implements ICredentialType {
    name = 'myApiCredential';
    displayName = 'My API Credential';
    properties: INodeProperties[] = [
        {
            displayName: 'API Key',
            name: 'apiKey',
            type: 'string',
            default: '',
        },
    ];
}

Step 4: Use your credential

In your custom node, you can reference this credential to authenticate API requests.

c. Modifying Existing Node Behavior

If you want to change how an existing node works (for example, to fix a bug or add new features), you can edit the source code of that node.

  • Find the node file inside packages/nodes-base/nodes.
  • Make your changes carefully.
  • Test thoroughly to ensure nothing breaks.

Modifying the Frontend (UI)

While backend changes control functionality, frontend modifications control how users interact with n8n.

Step 1: Locate the UI code

Frontend source lives in the packages/editor-ui directory. It’s built with Vue.js.

Step 2: Run the UI separately (optional)

If you want to work only on the UI without running the backend:

Bash
cd packages/editor-ui
npm install
npm run serve

The UI will run at http://localhost:8080.

Step 3: Common areas to customize

  • Themes and Styles:

    Change colors, fonts, or layout by editing CSS or Vue component styles. You can add your own theme files or modify existing ones.

  • Node Appearance:

    Nodes have Vue components that control their display inside the workflow editor. You can add extra info, change icons, or adjust how parameters are shown.

  • Workflow Editor Features:

    Add new buttons, modify toolbar options, or change drag-and-drop behavior by editing Vue components and their logic.

Example: Changing Node Icons

Node icons are stored in the resources folder. You can replace an icon or add a new one for your custom node by updating the icon path in the node’s description.

Common Use Cases for Customization

Many organizations customize n8n for their specific needs. Some common reasons include:

  • Branding:

    Make the UI match your company’s colors and logos for a seamless user experience.

  • Connecting Private APIs:

    Add nodes that connect to internal or proprietary APIs that are not publicly available.

  • Advanced Business Logic:

    Create complex nodes that perform calculations, data transformations, or trigger external processes specific to your workflows.

  • User Permissions and Access Control:

    Modify UI or backend logic to restrict access based on roles or departments.

  • Integrations with Legacy Systems:

    Build nodes that connect to older systems without modern APIs.

Testing Your Modifications

Testing is essential to ensure your modifications work correctly and don’t break existing functionality.

Automated Tests

  • n8n includes unit tests and integration tests for many nodes and UI components.
  • Write your own tests to cover new nodes or credential types using Jest or similar frameworks.
  • Run all tests with:
Bash
npm test

Manual Testing in the Editor

  • Build sample workflows using your custom nodes.
  • Check input and output data carefully.
  • Monitor logs for errors or warnings.
  • Use breakpoints or console.log() statements for debugging.

Deploying Your Custom Version

Once your customizations are tested and ready, you need to deploy your version of n8n so others can use it.

Deployment Options

  • Docker:

    Build a Docker image from your modified code and deploy it to any container environment.

  • Local Server:

    Run n8n on your own server or cloud VM using Node.js.

  • Managed Cloud:

    Deploy on platforms like AWS, Azure, or DigitalOcean with your custom build.

Keeping Your Custom Version Up to Date

n8n is actively maintained, so new versions come with improvements and security fixes. To stay current:

  • Regularly pull changes from the official repo.
  • Test updates against your custom features.
  • Merge upstream changes carefully to avoid conflicts.

Using Git branches and feature flags can help manage your customizations alongside official updates.

Contributing Back to n8n

If you believe your modifications can benefit others, contributing to the official project is a great idea.

How to Contribute

  • Fork the official n8n GitHub repo.
  • Create a branch for your feature or fix.
  • Follow the contribution guidelines.
  • Write clean, well-documented code.
  • Add tests if applicable.
  • Open a pull request describing your changes.

When to Contribute vs. Maintain a Fork

  • Contribute if your changes are useful for the general community.
  • Maintain a fork if your changes are very specific to your company or involve proprietary logic.

Conclusion

Modifying n8n unlocks endless possibilities to automate workflows tailored exactly to your needs. This flexibility is what sets n8n apart as a powerful, open-source automation platform.

In this guide, you’ve learned about:

  • The basic architecture of n8n.
  • Setting up a development environment.
  • How to build custom backend nodes and credentials.
  • Tweaking the frontend user interface.
  • Testing your changes.
  • Deploying your customized n8n.
  • Contributing your work back to the community.

With these insights and practical steps, you’re well-equipped to take full control of n8n and create automation solutions that truly fit your requirements. So, go ahead—explore, experiment, and build the next generation of workflow automations with n8n!