N8N for Beginners: Looping over Items

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Last update 9 months ago

N8N for Beginners: Looping Over Items

Description

This workflow is designed for n8n beginners to understand how n8n handles looping (iteration) over multiple items. It highlights two key behaviors:

Built-In Looping: By default, most n8n nodes iterate over each item in an input array.
Explicit Looping: The Loop Over Items node allows controlled iteration, enabling custom batch processing and multi-step workflows.

This workflow demonstrates the difference between processing an unsplit array of strings (single item) vs. a split array (multiple items).

Setup

1. Input Data

To begin, paste the following JSON into the Manual Trigger node:

{
  "urls": [
    "https://www.reddit.com",
    "https://www.n8n.io/",
    "https://n8n.io/",
    "https://supabase.com/",
    "https://duckduckgo.com/"
  ]
}

📌 Steps to Paste Data:

Double-click the "Manual Trigger" node.
Click "Edit Output" (top-right corner).
Paste the JSON and Save.
The node turns purple, indicating that test data is pinned.

1. Click "Test Workflow" button at the bottom of the canvas

Explanation of the n8n Nodes in the Workflow

Node Name	Purpose	Documentation Link
Manual Trigger	Starts the workflow manually and sends test data	Docs
Split Out	Converts an array of strings into separate JSON objects	Docs
Loop Over Items (Loop Over Items 1)	Demonstrates how an unsplit array is treated as one item	Docs
Loop Over Items (Loop Over Items 2)	Iterates over each item separately	Docs
Wait	Introduces a delay per iteration (set to 1 second)	Docs
Code	Adds a constant parameter (`param1`) to each item	Docs
NoOp (Result Nodes)	Displays output for inspection	Docs

Execution Details

1. How the Workflow Runs

Manual Trigger starts execution with the pasted JSON data.
The workflow follows two paths:
1. Unsplit Array Path → Loop Over Items 1
  - Processes the entire array as a single item.
  - Result1 & Result5: Show that the array was not split.
2. Split Array Path → Split Out → Loop Over Items 2
  - Splits the array into separate objects.
  - Result2, Result3, Result4: Show that each item is processed individually.
  - A Wait node (1 sec delay) demonstrates controlled execution.
  - Code nodes modify the JSON, adding a parameter (param1).

2. What You Will See

Node	Expected Output
Result1 & Result5	The entire array is processed as one item.
Result2, Result3, Result4	The array is split and processed as individual items.
Wait Node	Adds a 1-second delay per item in Loop Over Items 2.

Use Cases

This workflow is useful for:

✅ API Data Processing: Loop through API responses containing arrays.
✅ Web Scraping: Process multiple URLs individually.
✅ Task Automation: Execute a sequence of actions per item.
✅ Workflow Optimization: Control execution order, delays, and dependencies.

Notes

Sticky notes are included in the workflow for easy reference.
The Wait node is optional—remove it for faster execution.
This template is structured for beginners but serves as a building block for more advanced automations.