Custom Node Builder

Custom Nodes let you create your own reusable Gumloop nodes using AI. Describe what you want in plain language, and Gumloop generates the code for you. Once created, you can save, share, and reuse your custom node across any workflow.

Custom Nodes cost 3 credits per execution and run in an isolated virtual environment with a 5-minute runtime limit.

What Are Custom Nodes?

Custom Nodes allow you to build your own Gumloop nodes, define custom functionality, share with your team, deploy with one click, and integrate with any API or service.

Creating a Custom Node

You can find the custom node builder through the node library: Step 1: Open the Node Library Click the node library button or press Cmd/Ctrl + B, then select Your Custom Nodes.

Node library showing Your Custom Nodes section

Step 2: Describe Your Node Enter a clear description of what you want the node to do. Be specific about inputs, outputs, and the transformation logic.

Step 3: Generate and Test Click Generate and Gumloop’s AI will create the node for you. Test it with sample data before saving.

Node Structure

Custom nodes have three main components that you can configure:

Component	Description
Inputs	Dynamic data inputs with multiple fields, custom names, and various data types including files
Parameters	Configuration options like text fields, dropdowns, true/false toggles, and multiselect
Outputs	Define output format with multiple outputs, custom naming, and list or single values

When to Use Custom Nodes

Use Custom Nodes when you need to:

Use Case	Description
Create Integrations	Access internal APIs, company tools, or custom services not available as built-in nodes
Streamline Operations	Combine multiple steps and standardize processes into a single reusable node
Build Missing Features	New functionalities, specific use cases, or unique requirements for your workflows

Common Use Cases

API Integration

Purpose: Call internal endpoints
Features: Authentication, data cleaning
Share: Team can reuse

Data Processing

Purpose: Custom data transformations
Features: Specific formatting rules
Use-case: Processing complex or large files

Tool Connection

Purpose: Connect external services
Features: Custom API calls
Use-case: Accessing integrations not already available on Gumloop

Custom nodes can be shared with teammates and collaborators. By default, only the creator (Owner) can edit a custom node, but you can grant access to others with different roles. Step 1: Open the Share Dialog Hover over the custom node and click the Share button.

Step 2: Add Users by Email Enter the user’s email and choose their role from the Share dropdown:

Editor: Can view, edit, and manage the custom node
Viewer: Can view and use the custom node in their workflows, but cannot edit it

You can also set General Access to share the node with your entire team, organization, or anyone with the link.

Important Considerations

Consideration	Details
AI-Generated Code	The AI writes the code for you based on your description, no coding required
Secure Credentials	Use the secrets management system to handle API keys and tokens securely
Role-Based Access	Share as Editor (full access) or Viewer (use only). The creator is always the Owner.
Sharing Access	Share with any Gumloop user by email, or set General Access for broader reach
Iterative Development	The AI maintains context of your code, so you can refine it with follow-up prompts

Using Secrets in Custom Nodes

Custom nodes often need to access sensitive data like API keys, tokens, or credentials. Gumloop provides a secure secrets management system that lets you store encrypted secrets and use them in your custom nodes without exposing them in your code or logs.

Setting Up Secrets

Before using secrets in a custom node, you need to create them in your Personal Secrets settings: Step 1: Navigate to Personal Secrets Go to Settings > Profile > Secrets or visit gumloop.com/settings/profile/secrets.

Personal Secrets page showing empty state

Step 2: Add a New Secret Click + Add Secret to open the creation dialog. Enter a descriptive name for your secret (this is how you’ll reference it later) and the secret value. The value will be encrypted and stored securely.

Add Secret dialog with name and value fields

Step 3: Manage Your Secrets Your secrets appear in a list showing the name and last updated time. You can edit or delete secrets as needed. Note that secret values are never displayed after creation for security.

Personal Secrets list showing saved secrets

How Secrets Work in Custom Nodes

When you describe a custom node that needs API credentials or sensitive data, Gumloop’s AI automatically generates code that accesses these values through environment variables using os.getenv() or os.environ.get(). This keeps your secrets out of the code itself.

Example Prompts

Here are some example prompts that demonstrate how to request secrets in your custom nodes: Example 1: API Integration with Authentication

Create a node that makes a REST API call to any endpoint.
Accept parameters for: API endpoint URL, request method (GET/POST/PUT/DELETE), and request body.
Use an API key from an environment variable for authentication in the Authorization header.
Return the API response and status code.

Example 2: Database Connection

Create a node that connects to a PostgreSQL database and runs a query.
Use environment variables for the database connection string and credentials.
Accept a SQL query as input and return the results as a list.

Example 3: Third-Party Service Integration

Create a node that sends SMS messages using Twilio.
Use environment variables for the Twilio Account SID and Auth Token.
Accept phone number and message text as inputs.
Return the message SID on success.

Generated Code Example

When you use a prompt like Example 1 above, the AI generates code that retrieves secrets from environment variables. Here’s what the generated code looks like:

Custom node builder showing environment variables picker and generated code

The code uses os.getenv() to retrieve the secret value at runtime:

import os
import requests

# Retrieve API key from environment variable
api_key: str | None = os.getenv('TEST_SECRET_API_KEY')
if not api_key:
    return _error('Missing TEST_SECRET_API_KEY environment variable', 401)

# Use the API key in the Authorization header
headers: dict[str, str] = {'Authorization': f'Bearer {api_key}'}

# Make the API request
response = requests.get(endpoint_url, headers=headers)

Mapping Secrets to Environment Variables

After creating a custom node that requires environment variables, you’ll see an Environment Variables section in the node’s configuration panel. This is where you map your stored secrets to the variables the code expects.

Environment Variables dropdown showing available secrets

How to map secrets:

Locate the Environment Variables Section: When you add a custom node to your workflow that requires environment variables, you’ll see a picker for each required variable in the node’s settings panel on the left side.
Select Your Secret: Click the dropdown to see all secrets you’ve created in your Personal Secrets settings. Select the appropriate secret for each environment variable.
Add New Secrets Inline: If you haven’t created the required secret yet, click + Create new secret at the bottom of the dropdown to add a new secret without leaving the workflow builder.

Naming convention: Use descriptive, uppercase names with underscores for your secrets (e.g., OPENAI_API_KEY, STRIPE_SECRET_KEY, MY_SERVICE_TOKEN). This makes it clear what each secret is for and matches common environment variable conventions.

Security Features

Gumloop implements several security measures to protect your secrets:

Feature	Description
Encryption at rest	All secret values are encrypted before being stored in the database
Automatic redaction	Secret values are automatically redacted from logs, outputs, and error messages
No code exposure	Secrets are injected at runtime and never appear in your custom node’s code
Personal scope	Secrets are tied to your account and not shared with other users

Automatic Secret Redaction

If your custom node accidentally prints or returns a secret value, Gumloop automatically replaces it with ****SECRET_REDACTED**** in all logs and outputs. This prevents accidental exposure of sensitive data.

Secret redaction in action showing redacted output values

In the example above, you can see that even though the custom node outputs the secret value, it appears as ****SECRET_REDACTED**** in the run output. This redaction happens automatically for all secrets you’ve configured.

While automatic redaction protects against accidental exposure, it may make debugging harder. Avoid logging or printing sensitive values in your custom node code—instead, log descriptive messages about what your code is doing without including the actual secret values.

Best Practices for Secrets

When working with secrets in custom nodes, follow these guidelines:

✅ Do	❌ Don’t
Use descriptive names that indicate the secret’s purpose (e.g., `STRIPE_LIVE_KEY`, `OPENAI_API_KEY`)	Hardcode API keys or credentials directly in your prompts or code
Create separate secrets for different services—don’t reuse API keys across multiple integrations	Log or print secret values in your custom node code (they’ll be redacted, but it’s bad practice)
Update secrets promptly when you rotate credentials in the external service	Share workflows that require secrets without documenting which secrets are needed
Test your custom node with valid credentials before deploying to production workflows	Use generic names like `SECRET_1` or `API_KEY`—be specific about what each secret is for
Document which secrets are required when sharing workflows with teammates

Secrets vs. Node Credentials

Custom node secrets are different from the credential connections you see on integration nodes (like Gmail or Slack):

Aspect	Personal Secrets	Node Credentials
Purpose	API keys and tokens for custom code	OAuth connections to services
Setup	Manual entry in Settings	OAuth flow through Gumloop
Scope	Custom nodes and MCP nodes	Specific integration nodes
Management	Settings > Profile > Secrets	Per-node credential selector

Use Personal Secrets when you’re writing custom code that needs to authenticate with an API. Use Node Credentials when you’re using Gumloop’s built-in integration nodes.

Additional Resources

Custom Node Blog Post

Deep dive into custom node capabilities and use cases

Video Tutorial

Step-by-step walkthrough of building your first custom node

Custom Node Workshop

In-depth workshop covering advanced custom node techniques

Get Started

Core Concepts

Enterprise Features

Nodes

Common Errors

Custom Node Builder

What Are Custom Nodes?

Creating a Custom Node

Node Structure

When to Use Custom Nodes

Common Use Cases

Important Considerations

Using Secrets in Custom Nodes

Setting Up Secrets

How Secrets Work in Custom Nodes

Example Prompts

Generated Code Example

Mapping Secrets to Environment Variables

Security Features

Automatic Secret Redaction

Best Practices for Secrets

Secrets vs. Node Credentials

Additional Resources

Custom Node Blog Post

Video Tutorial

Custom Node Workshop

​What Are Custom Nodes?

​Creating a Custom Node

​Node Structure

​When to Use Custom Nodes

​Common Use Cases

​Sharing and Collaboration

​Sharing Your Custom Node

​Important Considerations

​Using Secrets in Custom Nodes

​Setting Up Secrets

​How Secrets Work in Custom Nodes

​Example Prompts

​Generated Code Example

​Mapping Secrets to Environment Variables

​Security Features

​Automatic Secret Redaction

​Best Practices for Secrets

​Secrets vs. Node Credentials

​Additional Resources

Custom Node Blog Post

Video Tutorial

Custom Node Workshop

What Are Custom Nodes?

Creating a Custom Node

Node Structure

When to Use Custom Nodes

Common Use Cases

Sharing and Collaboration

Sharing Your Custom Node

Important Considerations

Using Secrets in Custom Nodes

Setting Up Secrets

How Secrets Work in Custom Nodes

Example Prompts

Generated Code Example

Mapping Secrets to Environment Variables

Security Features

Automatic Secret Redaction

Best Practices for Secrets

Secrets vs. Node Credentials

Additional Resources