# N8n Code Python > Write Python code in n8n Code nodes. Use when writing Python for n8n, using Python libraries, pandas data processing, or preferring Python over JavaScript in workflows. Use when this capability is needed. - Skill: `tomevault-io/n8n-code-python` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/n8n-code-python` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/n8n-code-python/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Data & Analytics - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/n8n-code-python --- # n8n Code Python Expert guidance for writing Python in n8n Code nodes. > Based on [n8n-skills](https://github.com/czlonkowski/n8n-skills) by Romuald Członkowski ## Python Code Node Basics n8n supports Python in Code nodes with some differences from JavaScript. ### Run Once for All Items ```python # Access all input items items = _input.all() # Process and return return [{"json": {**item.json, "processed": True}} for item in items] ``` ### Run Once for Each Item ```python # Access current item data = _input.item.json # Return single item return {"json": {**data, "processed": True}} ``` ## Accessing Data ### Current Node Input ```python # All items items = _input.all() # First item first = _input.first() # Current item (in "each item" mode) current = _input.item # JSON data data = _input.first().json ``` ### Execution Context ```python # Note: Limited compared to JavaScript # Access via items or hardcoded values ``` ## Common Patterns ### Transform All Items ```python items = _input.all() return [ { "json": { "id": item.json["id"], "name": item.json["name"].upper(), "processed": True } } for item in items ] ``` ### Filter Items ```python items = _input.all() return [ {"json": item.json} for item in items if item.json.get("status") == "active" ] ``` ### Aggregate Data ```python items = _input.all() total = sum(item.json.get("amount", 0) for item in items) count = len(items) return [{ "json": { "total": total, "count": count, "average": total / count if count > 0 else 0 } }] ``` ### Group By ```python from collections import defaultdict items = _input.all() grouped = defaultdict(list) for item in items: key = item.json.get("category", "unknown") grouped[key].append(item.json) return [ {"json": {"category": k, "items": v, "count": len(v)}} for k, v in grouped.items() ] ``` ### JSON Parsing ```python import json items = _input.all() return [ { "json": { "parsed": json.loads(item.json.get("rawData", "{}")) } } for item in items ] ``` ### Error Handling ```python import json items = _input.all() results = [] for item in items: try: parsed = json.loads(item.json.get("rawData", "{}")) results.append({"json": {"success": True, "data": parsed}}) except Exception as e: results.append({"json": {"success": False, "error": str(e)}}) return results ``` ## Date/Time Handling ```python from datetime import datetime, timedelta # Current time now = datetime.now() # Parse ISO date date = datetime.fromisoformat("2024-01-15T10:30:00") # Format formatted = now.strftime("%Y-%m-%d %H:%M:%S") # Add/subtract next_week = now + timedelta(days=7) yesterday = now - timedelta(days=1) # Return with dates return [{ "json": { "now": now.isoformat(), "formatted": formatted, "nextWeek": next_week.isoformat() } }] ``` ## Working with Pandas ⚠️ **Note**: pandas may not be available in all n8n installations. Check your environment. ```python import pandas as pd items = _input.all() # Convert to DataFrame data = [item.json for item in items] df = pd.DataFrame(data) # Process with pandas df["total"] = df["price"] * df["quantity"] df_grouped = df.groupby("category").agg({"total": "sum"}).reset_index() # Convert back to n8n format return [{"json": row} for row in df_grouped.to_dict(orient="records")] ``` ## Webhook Data Access **CRITICAL**: Webhook data is under `.body`: ```python # ❌ Wrong message = _input.first().json.get("message") # ✅ Correct - webhook data is in body body = _input.first().json.get("body", {}) message = body.get("message") headers = _input.first().json.get("headers", {}) query = _input.first().json.get("query", {}) ``` ## Available Libraries Standard Python libraries typically available: - `json` - JSON parsing - `datetime` - Date/time handling - `re` - Regular expressions - `collections` - Data structures - `math` - Mathematical functions - `base64` - Encoding - `hashlib` - Hashing ```python import json import re import hashlib from datetime import datetime from collections import defaultdict # Use hashlib hash_value = hashlib.sha256(data.encode()).hexdigest() # Use regex matches = re.findall(r"\d+", text) ``` ## Common Mistakes ### 1. Wrong Return Format ```python # ❌ Wrong - must return list of dicts with "json" key return {"name": "John"} # ✅ Correct return [{"json": {"name": "John"}}] ``` ### 2. Using dot notation for dict access ```python # ❌ Wrong - Python dicts use brackets name = item.json.name # ✅ Correct name = item.json["name"] # or safer: name = item.json.get("name", "default") ``` ### 3. Not Handling Missing Keys ```python # ❌ Wrong - KeyError if missing value = item.json["optional_field"] # ✅ Correct value = item.json.get("optional_field", "default") ``` ### 4. Returning dict instead of list ```python # ❌ Wrong in "all items" mode return {"json": {"result": "data"}} # ✅ Correct - always return list return [{"json": {"result": "data"}}] ``` ## Python vs JavaScript in n8n | Feature | Python | JavaScript | |---------|--------|------------| | Input access | `_input` | `$input` | | Node access | Limited | `$node["Name"]` | | Env vars | Limited | `$env.VAR` | | Async/await | No | Yes | | Libraries | Standard + limited | Luxon, Lodash | ## Best Practices 1. **Always return list** of `{"json": {...}}` dicts 2. **Use `.get()`** for safe dict access 3. **Handle exceptions** with try/except 4. **Import at top** of code block 5. **Test with simple data** first 6. **Access webhook data** via `.body` ## Quick Reference | Need | Code | |------|------| | All items | `_input.all()` | | First item | `_input.first()` | | Current item | `_input.item` (each mode) | | Item JSON | `item.json` | | Dict value | `item.json.get("key", default)` | | Webhook body | `item.json.get("body", {})` | | Return item | `{"json": {...}}` | | Return many | `[{"json": {...}}, ...]` | --- Based on [n8n-skills](https://github.com/czlonkowski/n8n-skills) by Romuald Członkowski • Adapted for Moltbot by fazer.ai --- > Source: [fazer-ai/moltbot-skill-n8n](https://github.com/fazer-ai/moltbot-skill-n8n) — distributed by [TomeVault](https://tomevault.io).