n8n-code-python

Python Code Node (Beta)

Expert guidance for writing Python code in n8n Code nodes.

⚠️ Important: JavaScript First

Recommendation: Use JavaScript for 95% of use cases. Only use Python when:

• You need specific Python standard library functions
• You're significantly more comfortable with Python syntax
• You're doing data transformations better suited to Python

Why JavaScript is preferred:

• Full n8n helper functions (this.helpers.httpRequest, etc.)
• Luxon DateTime library for advanced date/time operations
• No external library limitations
• Better n8n documentation and community support

Quick Start

# Basic template for Python Code nodes
items = _input.all()

# Process data
processed = []
for item in items:
    processed.append({
        "json": {
            **item["json"],
            "processed": True,
            "timestamp": datetime.now().isoformat()
        }
    })

return processed

Essential Rules

1. Consider JavaScript first - Use Python only when necessary
2. Access data: _input.all(), _input.first(), or _input.item
3. CRITICAL: Must return [{"json": {...}}] format
4. CRITICAL: Webhook data is under _json["body"] (not _json directly)
5. CRITICAL LIMITATION: No external libraries (no requests, pandas, numpy)
6. Standard library only: json, datetime, re, base64, hashlib, urllib.parse, math, random, statistics

Mode Selection Guide

Same as JavaScript - choose based on your use case:

Run Once for All Items (Recommended - Default)

Use this mode for: 95% of use cases

• How it works: Code executes once regardless of input count
• Data access: _input.all() or _items array (Native mode)
• Best for: Aggregation, filtering, batch processing, transformations
• Performance: Faster for multiple items (single execution)

# Example: Calculate total from all items
all_items = _input.all()
total = sum(item["json"].get("amount", 0) for item in all_items)

return [{
    "json": {
        "total": total,
        "count": len(all_items),
        "average": total / len(all_items) if all_items else 0
    }
}]