HTTP Listener Trigger

The HTTP Listener Trigger node enables you to expose API endpoints that external agents and systems can interact with. This powerful trigger combines the flexibility of custom HTTP endpoints with AI-assisted API contract design, making it easy to create professional, well-structured APIs for your workflows.

Why Use HTTP Listener Trigger?

The HTTP Listener Trigger is ideal when you need to:

Build production-grade APIs - Create professionally structured REST APIs with comprehensive request/response contracts
Leverage AI for API design - Use natural language to describe your API requirements and let AI generate the contract
Maintain API standards - Work with OpenAPI 3.0 specifications for industry-standard API documentation
Rapid prototyping - Quickly iterate on API designs with visual editing and AI assistance
Validate contracts - Catch errors early with real-time validation and intelligent fix suggestions

Use Cases

Common scenarios for using the HTTP Listener Trigger include:

Building REST APIs for mobile and web applications
Creating microservices endpoints with well-defined contracts
Exposing workflow automation as API services
Developing integration endpoints with third-party systems
Prototyping and testing API designs before implementation

Key Features

AI-Powered Contract Design

The HTTP Listener Trigger features an integrated AI Copilot that revolutionizes how you design APIs:

Natural language to API contract - Describe your API in plain English and get a complete OpenAPI specification
Intelligent error fixing - Automatically detect and fix validation errors in your API contract
Dual-mode editing - Switch seamlessly between visual editor and OpenAPI code view
Real-time validation - Get instant feedback with VS Code-like error highlighting
Quick Fix integration - Click on errors to automatically generate AI prompts for fixes

This makes API design accessible to everyone, from developers to business analysts.

Configuration Steps

Setting up the HTTP Listener Trigger involves 5 steps. The configuration panel guides you through each step, showing your progress at the top.

HTTP Listener configuration panel showing 5 steps

Step 1: Endpoint Configuration

Define how external systems will access your HTTP endpoint.

Endpoint configuration showing path and methods

Endpoint Path

Base path - Auto-generated based on your tenant and environment

Example: /http-listener/knowledgebase-uc1

This base path is read-only and automatically created by the system.

Path segment - The unique identifier for this endpoint

Enter a custom path segment that describes your endpoint's purpose. This will be appended to the base path.

Example: / default-trigger

Generated URL - The complete endpoint URL

The system automatically constructs your full endpoint URL by combining the base path and path segment.

Example: https://customer01-dev.api.flowgenx.ai/http-listener/knowledgebase-uc1/default-trigger

Click the copy icon to easily copy the URL for use in external systems.

HTTP Methods

Select which HTTP methods your endpoint will accept:

GET - Retrieve data
POST - Create new resources
PUT - Update entire resources
PATCH - Partially update resources
DELETE - Remove resources

You can select one or more HTTP methods this endpoint will accept. The interface shows which methods are currently enabled with highlighted buttons.

Tip: Choose methods that align with RESTful best practices for the operation your endpoint performs.

Timeout

Maximum time to wait for a response - Configure how long requests can run before timing out

Default: 30s

Accepted formats: 30s, 5m, 1h

This prevents long-running requests from consuming resources indefinitely.

Click Next to proceed to security configuration.

Step 2: Security Settings

Configure authentication and access control for your HTTP endpoint.

Security configuration showing authentication options

The security configuration for HTTP Listener follows the same pattern as other trigger nodes, allowing you to:

Enable or disable authentication requirements
Choose authentication methods (API Key, Bearer Token, OAuth 2.0)
Configure rate limiting to prevent abuse
Enable CORS for browser-based requests

For detailed information on each security option, see the Webhook Trigger security documentation.

Click Next to configure your API contract.

Step 3: API Contract

This is where the HTTP Listener Trigger truly shines. The Contract step provides a powerful, AI-assisted interface for designing your API's request and response structure.

API Contract visual editor showing request and response definition

Understanding the Contract Interface

The Contract step offers two powerful editing modes:

Visual Editor - Graphical interface for defining API structure

Add fields with drag-and-drop simplicity
Configure field types, requirements, and validations
Organize complex nested objects and arrays
Perfect for visual thinkers and rapid prototyping

OpenAPI Spec - Code-based OpenAPI 3.0 specification editor

Full OpenAPI 3.0 standard compliance
Syntax highlighting and code folding
Direct access to all OpenAPI features
Ideal for developers who prefer code-first approaches

Both modes stay in perfect sync - changes in one automatically update the other.

Endpoint Path Configuration

At the top of the contract editor, you can refine your endpoint path:

Base path - Your auto-generated base path Path segment - Customize the endpoint identifier

Use {paramName} syntax for path parameters (no leading /).

Example: default-trigger or users/{userId}/orders

The Generated URL displays your complete endpoint with all path segments.

Request Definition

Define what data your API expects to receive from callers.

The Request Definition section includes four tabs:

Body - Define the JSON request body schema

Add fields with the + Add Field button
Specify field names, types, and requirements
Create nested objects with + Child Field
Support for all JSON data types: String, Number, Boolean, Object, Array

Query - Define URL query parameters

Configure optional and required query params
Specify data types and validation rules

Path - Define path parameters

Extract variables from the URL path
Type validation for path segments

Headers - Define expected HTTP headers

Custom header requirements
Standard headers (Authorization, Content-Type, etc.)

Example: Adding Body Fields

In the visual editor, you can see fields like:

field1 (String)
field2 (Object) with nested properties:
- property1 (String)
- property2 (String)

Each field shows:

Validation status (green checkmark)
Field type icon (T for text, for object)
Type dropdown (String, Object, Number, etc.)
Required checkbox
Delete button

Response Definition

Define what your API will return to callers.

The Response Definition section includes:

Success (200) - Define successful response structure

HTTP Status Code: 200 OK (default)
Response Fields with types and structure

Error (500) - Define error response structure

HTTP Status Code: 500 (or customize)
Error message format and fields

Response Fields

Add fields for successful responses
Define error response formats
Specify field types and requirements

The interface shows "No response fields defined" when you haven't added any fields yet. Click + Add Field to start building your response contract.

OpenAPI Spec Mode

Switch to OpenAPI Spec tab to see the complete OpenAPI 3.0 specification in code format.

Features:

Syntax highlighting - Color-coded JSON for easy reading
Code folding - Collapse/expand sections with chevron icons
Line numbers - Easy reference and navigation
Real-time sync - Changes sync automatically with Visual Editor
Copy button - Export the complete specification
Minimap - Visual overview of the entire document (shown on right side)

OpenAPI 3.0 Specification Structure:

{
  "openapi": "3.0.3",
  "paths": {
    "/http-listener/knowledgebase-uc1/default-trigger": {
      "post": {
        "summary": "POST /http-listener/knowledgebase-uc1/default-trigger",
        "operationId": "posthttplistenerknowledgebaseuc1defaulttrigger",
        "parameters": [],
        "responses": {
          "200": {
            "description": "Successful response",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {}
                }
              }
            }
          }
        }
      }
    }
  }
}

Note: Edit the OpenAPI spec - changes sync back to visual editor. This bidirectional synchronization ensures consistency between both editing modes.

AI Copilot: Your API Design Assistant

The AI Copilot is the standout feature of the HTTP Listener Trigger, making API design accessible and efficient.

AI Copilot panel for natural language API design

Opening the AI Copilot

Click the AI Copilot button in the top-right corner of the Contract section. A panel slides in from the left, giving you access to AI-powered contract generation.

How to Use AI Copilot

1. Describe your API in natural language

The AI Copilot provides example prompts to get you started:

"User registration"
"Create order"
"Search API"
"File upload"

Simply type what you want your API to do in plain English.

Example prompt:

Create an API for user registration that accepts email, password,
and optional phone number, and returns a user ID and success message

2. Get AI-generated contract

The AI analyzes your description and generates:

Complete request body schema
Response structure
Appropriate field types and validations
Nested objects where needed
Required vs optional field designations

3. Review the generated contract

The AI Copilot displays the generated contract in a collapsible preview:

Generated Contract (3 fields)
Request Body
  field1: string
  field2: object
    property1: string
    property2: string
  pages: array (NEW)
    items: string

New fields are marked with a NEW badge for easy identification.

4. Apply changes

You have multiple options for applying AI-generated contracts based on the new changes generated by ai copilot:

Apply All
Apply Body
Apply Response
Apply Params
Apply Header

Click your preferred option, and the changes instantly appear in both the Visual Editor and OpenAPI Spec views.

AI-Powered Error Detection and Fixing

The HTTP Listener Trigger includes sophisticated error detection that rivals professional IDEs.

Real-time Validation

As you edit in OpenAPI Spec mode, the system continuously validates your specification:

Error indicators:

Red underlines - Just like VS Code, errors are underlined in red
Error count badge - "1 error to fix" badge shows total issues
Hover tooltips - Hover over errors to see detailed descriptions
Minimap markers - Errors show as red marks in the minimap

Example error:

Array field "requestBody.pages" must define items.type

Quick Fix Feature

When errors are detected, you can click Quick Fix to automatically generate an AI prompt for resolution.

What happens when you click Quick Fix:

The AI Copilot panel automatically opens (if not already open)
A context-aware prompt is auto-generated and populated in the input field
The prompt includes the specific error context

Example auto-generated prompt:

Fix this error in the OpenAPI specification:

Code/Error context:
`json
Array field 'requestBody.pages' must define items.type
...

Please suggest the corrected version.

The AI understands the error and generates a precise fix.

Applying AI-Generated Fixes

AI Copilot showing generated fix with Apply options

After the AI processes the error:

1. Review the fix

The AI Copilot displays:

Clear explanation of the issue
The corrected contract structure
What was added or changed

Example AI response:

Added 'items' definition to the 'pages' array field to specify
the type of items it contains.

Generated Contract (3 fields)
Request Body
  field1: string
  field2: object
    property1: string
    property2: string
  pages: array
    items: string

2. Apply the fix

Click Apply All to apply the corrected contract. The fix is instantly applied to both:

Visual Editor (fields update visually)
OpenAPI Spec (code is corrected automatically)

3. Verification

After applying:

Red error underlines disappear
Error count badge is removed
The contract passes validation
Both editing modes show the corrected structure

AI Copilot Best Practices

Be specific in descriptions

Include field names and types you want
Specify which fields are required vs optional
Mention any validation requirements
Describe nested structures clearly

Iterate with AI

Start with a basic description
Review the generated contract
Refine with follow-up prompts
Build complex APIs incrementally

Leverage Quick Fix

Don't manually debug OpenAPI errors
Click Quick Fix for intelligent error resolution
Let AI explain what's wrong and how to fix it
Learn OpenAPI best practices through AI suggestions

Combine manual and AI editing

Use AI for initial contract generation
Fine-tune details in Visual Editor
Verify in OpenAPI Spec mode
Add AI-generated improvements as needed

Contract Validation

The system performs comprehensive validation on your API contract:

Visual Editor validation:

Field type consistency
Required field completeness
Nested structure validity
Data type compatibility

OpenAPI Spec validation:

Schema compliance with OpenAPI 3.0
Required property definitions
Format and structure correctness
Referenced component validity

Common validation errors:

Missing required properties
Invalid data type definitions
Incomplete array item specifications
Malformed nested objects
Invalid OpenAPI syntax

All errors are highlighted in real-time, allowing you to fix issues before deploying.

Preview and Export

Preview - Click the Preview button to see how your API documentation will appear

Export OpenAPI - Click Export OpenAPI to download the complete OpenAPI 3.0 specification file

This exported file can be:

Imported into API documentation tools (Swagger UI, Redoc)
Shared with API consumers
Used for API testing tools (Postman, Insomnia)
Stored in version control

The field count (e.g., "4 fields") helps you track contract complexity at a glance.

Click Next to configure response mode.

Step 4: Response Mode

Configure how your HTTP endpoint responds to incoming requests. The response mode determines the interaction pattern between the caller and your workflow.

Response mode options include:

Synchronous Response - Wait for workflow completion before responding

Returns final workflow results to the caller
Best for quick operations under timeout limit
Provides immediate feedback with results

Asynchronous Response - Acknowledge immediately, process in background

Returns 202 Accepted status immediately
Workflow continues processing after response
Ideal for long-running operations

Custom Response Handling - Use ResponseToWebhook nodes in your workflow

Full control over when and what to respond
Support complex response scenarios
Advanced use cases with conditional responses

Choose the response mode that best fits your API's requirements and expected execution time.

Click Next to proceed to testing.

Step 5: Test & Deploy

Verify your HTTP Listener configuration and deploy your API endpoint.

Ready to Deploy

Deploy to make your endpoint accessible

Click the Deploy API button to:

Register the endpoint with the API gateway
Activate authentication and security rules
Make the endpoint accessible to external systems
Enable request routing to your workflow

The deployment process configures all the settings you defined in previous steps.

Test Request

Send a test payload to verify your configuration

The Test Request section allows you to:

Customize Test Request Body

Click to expand the test request panel
Edit the JSON payload for httplistener testing
Ensure the payload matches your contract definition
Include all required fields from your request schema

Send test requests to verify:

Request validation works correctly
Response structure matches your contract
Authentication is properly configured
Workflow execution completes as expected

Live Event Stream

Monitor incoming requests in real-time

The Live Event Stream provides real-time monitoring:

HttpListener Event Stream

Shows connection status (Disconnected/Connected)
Displays the listening endpoint path
Real-time event notifications

Connection controls:

Trash icon - Clear event log
Connection toggle - Start/stop listening
Audio notifications toggle

When disconnected:

Message: "Disconnected. Click the connect button in the top right to start receiving httplistener events."
Shows the HttpListener path being monitored
Displays connection status

Waiting for events:

Loading indicator appears
Message: "Waiting for httplistener events..."
Instructions to connect to the event stream
Current path: knowledgebase-uc1/default-trigger
Connection status: disconnected

Start listening:

Click Start Listening for Events button to:

Establish SSE (Server-Sent Events) connection
Begin receiving real-time event notifications
Monitor incoming HTTP requests
View request and response data

What you'll see when events arrive:

Event type (request, response, error)
Timestamp for each event
Expandable event details
Request payload data
Response status and data

This live monitoring helps you:

Verify requests are reaching your endpoint
Debug request/response issues
Monitor API usage in real-time
Validate contract compliance
Test end-to-end integration

Click Complete to finish configuration.

Using the HTTP Listener in Your Workflow

After configuration is complete:

The HTTP Listener Trigger node appears at the start of your workflow
Deploy your workflow and the API endpoint
External systems can send HTTP requests to your endpoint
Each valid request triggers workflow execution
Request data is validated against your contract
Response is returned according to your contract definition

Accessing Request Data

The HTTP Listener makes request data available to downstream nodes:

Available data includes:

Body - Parsed JSON request body (validated against contract)
Query parameters - URL query string values
Path parameters - Variables extracted from URL path
Headers - HTTP request headers
Metadata - Request timestamp, correlation ID, etc.

All data is typed and validated according to your API contract, ensuring data quality throughout your workflow.

Best Practices

API Contract Design

Start with AI - Use AI Copilot to generate initial contract structure
Validate early - Fix errors as they appear using Quick Fix
Be explicit - Define all required fields clearly in your contract
Use meaningful names - Choose descriptive field names that indicate purpose
Document your API - Use the OpenAPI description fields for documentation
Version your contracts - Consider versioning strategy for API evolution

AI Copilot Usage

Be specific - Provide detailed descriptions for better AI-generated contracts
Iterate - Refine AI suggestions with follow-up prompts
Review before applying - Always review AI-generated contracts before applying
Learn from AI - Study AI-generated OpenAPI specs to learn best practices
Use Quick Fix liberally - Let AI help you resolve validation errors
Combine approaches - Mix AI generation with manual refinement

Contract Validation

Test both modes - Verify your contract in both Visual Editor and OpenAPI Spec
Use Preview - Check how your API documentation will appear
Export and review - Export OpenAPI spec for external validation
Validate data types - Ensure field types match your workflow needs
Define error responses - Don't forget to specify error response schemas

Security and Performance

Always use authentication - Never deploy public APIs without authentication
Set appropriate timeouts - Match timeout to expected execution time
Rate limit - Protect your endpoint from abuse with rate limiting
Validate input - Rely on your contract validation to ensure data quality
Monitor usage - Use Live Event Stream to watch for unusual patterns

Testing Strategy

Test with contract-compliant data - Ensure test payloads match your schema
Test validation - Send invalid data to verify contract enforcement
Test all HTTP methods - Verify each enabled method works correctly
Monitor event stream - Watch requests in real-time during testing
Test error scenarios - Verify error responses match your contract

Advanced Features

Complex Data Structures

The Visual Editor and AI Copilot support sophisticated data structures:

Nested Objects

Create hierarchical data models
Define object properties at any depth
Use "+ Child Field" for nested properties

Arrays

Define array fields with item types
Support arrays of primitives or objects
Specify array item schemas

Mixed Types

Combine strings, numbers, booleans, objects, and arrays
Create complex request/response contracts
Model real-world data structures

OpenAPI 3.0 Compliance

The HTTP Listener generates fully compliant OpenAPI 3.0 specifications:

Standard format - Compatible with all OpenAPI tools
Complete documentation - Includes descriptions, examples, schemas
Extensible - Add custom OpenAPI extensions
Portable - Export and use in any OpenAPI-compatible system

Bidirectional Synchronization

The Visual Editor and OpenAPI Spec stay perfectly synchronized:

Edit visually - Changes appear instantly in OpenAPI Spec
Edit code - Changes reflect immediately in Visual Editor
No conflicts - Synchronization is automatic and seamless
Choose your preference - Work in the mode that suits you best

Troubleshooting

Contract Validation Errors

Problem: Red underlines in OpenAPI Spec

Solutions:

Hover over the error to see the description
Click Quick Fix to auto-generate an AI prompt
Let AI Copilot suggest the correction
Apply the fix with Apply All

Problem: Fields not showing in Visual Editor

Solutions:

Check OpenAPI Spec for syntax errors
Ensure proper JSON structure
Verify field definitions are complete
Switch to OpenAPI Spec to identify issues

AI Copilot Issues

Problem: AI generates incorrect contract

Solutions:

Provide more specific description
Include field names and types explicitly
Use follow-up prompts to refine
Manually adjust in Visual Editor after applying

Problem: Quick Fix doesn't work

Solutions:

Ensure error is selected correctly
Check that AI Copilot panel opened
Manually copy error context if needed
Review generated prompt before sending

Deployment Issues

Problem: API not accessible after deployment

Solutions:

Verify workflow is published
Check "Deploy API" was clicked
Confirm endpoint URL is correct
Review security settings for authentication

Problem: Requests fail validation

Solutions:

Compare request payload to contract schema
Check required fields are present
Verify data types match contract
Review error messages for specifics

Testing Issues

Problem: Test request fails

Solutions:

Ensure test payload matches contract
Check required fields are included
Verify authentication credentials
Review Live Event Stream for errors

Problem: Event stream not showing events

Solutions:

Click "Start Listening for Events" button
Verify endpoint is deployed
Check workflow is published
Ensure requests are reaching the endpoint

Monitoring and Debugging

Contract Validation

Visual indicators - Green checkmarks show valid fields
Error highlighting - Red underlines mark issues
Error count - Badge shows total errors to fix
Quick Fix - One-click error resolution

Request Monitoring

Live Event Stream - Real-time request/response monitoring
Event details - Expandable event information
Timestamps - Track when requests occur
Connection status - Know when monitoring is active

API Documentation

Preview - See formatted API documentation
Export OpenAPI - Generate complete specification file
Field count - Track contract complexity
Version tracking - Monitor contract changes

For comprehensive execution monitoring, see the Traceability documentation.

Next Steps

After setting up your HTTP Listener Trigger:

Design your API contract - Use AI Copilot to create a professional contract
Validate thoroughly - Fix any errors using Quick Fix and AI assistance
Add processing nodes - Build your workflow to handle requests
Test with real data - Send test requests and monitor the event stream
Export documentation - Generate OpenAPI spec for API consumers
Deploy to production - Publish workflow and deploy the API endpoint
Monitor usage - Track requests and optimize performance

The HTTP Listener Trigger combines the power of professional API design with the simplicity of AI-assisted development, enabling you to build production-grade APIs in minutes rather than hours.

HTTP Listener Trigger

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