Core Concepts¶

This guide explains the fundamental concepts in m9m workflow automation.

Workflows¶

A workflow is a directed graph of nodes that defines an automated process. Workflows consist of:

Nodes - Individual processing steps
Connections - Data flow paths between nodes
Settings - Workflow-level configuration

Workflow Structure¶

{
  "name": "Example Workflow",
  "nodes": [...],
  "connections": {...},
  "settings": {...},
  "active": true
}

Workflow States¶

State	Description
`active`	Workflow is enabled and can be triggered
`inactive`	Workflow is disabled

Nodes¶

Nodes are the building blocks of workflows. Each node performs a specific operation.

Node Structure¶

{
  "id": "unique-id",
  "name": "Display Name",
  "type": "n8n-nodes-base.httpRequest",
  "position": [x, y],
  "parameters": {...},
  "disabled": false
}

Node Categories¶

Category	Description	Examples
Core	Workflow control	Start
Trigger	Start workflows	Webhook, Cron
Transform	Data manipulation	Set, Filter, Code
HTTP	Web requests	HTTP Request
Database	Data storage	PostgreSQL, MySQL
Messaging	Communication	Slack, Discord
AI	AI/ML operations	OpenAI, Anthropic
Cloud	Cloud services	AWS S3, Azure Blob
VCS	Version control	GitHub, GitLab

Node Parameters¶

Parameters configure node behavior. They support:

Static values: "url": "https://api.example.com"
Expressions: "url": "={{ $json.endpoint }}"

Data Items¶

Data flows through workflows as items. Each item is a JSON object.

Item Structure¶

{
  "json": {
    "field1": "value1",
    "field2": 123
  },
  "binary": {
    "data": "base64-encoded..."
  }
}

Data Flow¶

┌─────────┐     ┌─────────┐     ┌─────────┐
│  Node A │────▶│  Node B │────▶│  Node C │
│         │     │         │     │         │
│ Output: │     │ Input:  │     │ Input:  │
│ [item1] │     │ [item1] │     │ [item2] │
│ [item2] │     │ [item2] │     │         │
└─────────┘     │ Output: │     └─────────┘
                │ [item2] │
                └─────────┘

Nodes receive all items from connected upstream nodes
Nodes can output zero, one, or many items
Data is passed by reference (not copied)

Connections¶

Connections define how data flows between nodes.

Connection Structure¶

{
  "Source Node Name": {
    "main": [
      [
        {"node": "Target Node", "type": "main", "index": 0}
      ]
    ]
  }
}

Connection Types¶

Type	Description
`main`	Primary data flow

Multiple Outputs¶

Some nodes have multiple outputs (e.g., Switch node):

{
  "Switch": {
    "main": [
      [{"node": "Path A", "type": "main", "index": 0}],
      [{"node": "Path B", "type": "main", "index": 0}]
    ]
  }
}

Expressions¶

Expressions allow dynamic values based on input data.

Syntax¶

// Full expression
={{ $json.fieldName }}

// Template string
Hello {{ $json.name }}!

// With operations
={{ $json.price * 1.1 }}

Available Variables¶

Variable	Description
`$json`	Current item's JSON data
`$item`	Current item index
`$now`	Current timestamp
`$env`	Environment variables
`$input`	All input items

See Expressions for complete documentation.

Executions¶

An execution is a single run of a workflow.

Execution States¶

State	Description
`pending`	Queued, waiting to run
`running`	Currently executing
`success`	Completed successfully
`failed`	Completed with errors
`cancelled`	Manually cancelled

Execution Data¶

Each execution stores:

Input data
Output data from each node
Error messages (if failed)
Timing information
Execution mode (manual, scheduled, webhook)

Credentials¶

Credentials securely store authentication data for external services.

Credential Structure¶

{
  "name": "My API Key",
  "type": "apiKey",
  "data": {
    "apiKey": "secret-value"
  }
}

Credential Types¶

Type	Used For
`apiKey`	API key authentication
`oauth2`	OAuth 2.0 flows
`basicAuth`	HTTP Basic Auth
`httpHeader`	Custom headers

Credentials are encrypted at rest and injected into node parameters at runtime.

Triggers¶

Triggers start workflow execution.

Trigger Types¶

Trigger	Description
Manual	Started via API or CLI
Webhook	HTTP request to endpoint
Schedule	Cron-based timing

Webhook Triggers¶

{
  "type": "n8n-nodes-base.webhook",
  "parameters": {
    "path": "/my-webhook",
    "httpMethod": "POST"
  }
}

Endpoint: http://localhost:8080/webhook/my-webhook

Scheduled Triggers¶

{
  "type": "n8n-nodes-base.cron",
  "parameters": {
    "cronExpression": "0 9 * * MON"
  }
}

Job Queue¶

m9m uses a job queue for workflow execution.

Queue Behavior¶

Workflow execution request → Job created
Job queued with status pending
Worker picks up job → status running
Execution completes → status success or failed

Queue Types¶

Type	Persistence	Use Case
`memory`	No	Development, testing
`sqlite`	Yes	Production (single node)

Summary¶

Concept	Description
Workflow	Directed graph of automated steps
Node	Single processing operation
Connection	Data flow path between nodes
Item	Unit of data (JSON object)
Expression	Dynamic value using input data
Execution	Single workflow run
Credential	Secure authentication storage
Trigger	Workflow start mechanism
Queue	Execution job management