n8n-code-python

# Python Code Node (Beta)

Expert guidance for writing Python code in n8n Code nodes.

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## ⚠️ 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 ($helpers.httpRequest, etc.)
- Luxon DateTime library for advanced date/time operations
- No external library limitations
- Better n8n documentation and community support

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## Quick Start

```python
# 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)

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