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).

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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

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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 |

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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. |

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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.

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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.

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