n8n-code-python

Python Code Node (native)

Since n8n 2.0 the Code node's Python runs as native Python in a task runner (language: "pythonNative"). The old Pyodide "Python (Beta)" is gone, and with it every n8n helper it had: _input, _json, _node, _now, _today and _jmespath all raise NameError now. Code copied from old templates, forum posts or older docs usually breaks on this.

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JavaScript first — stronger than before

Native Python gives you two variables and plain Python, and by default no imports: no json, datetime or re. Everything n8n-specific ($('Node'), $jmespath, Luxon, this.helpers.httpRequest, static data) exists only in JavaScript. Use Python only when the user explicitly asks for it. Even then, first check whether an expression, Edit Fields, or a native node (Crypto, Date & Time, HTML, XML) does the job. See n8n-code-javascript and the transform gatekeeper in n8n-expression-syntax.

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Quick start

# Run Once for All Items (default mode)
return [
    {"json": {"name": it["json"]["name"], "revenue": it["json"]["revenue"]}}
    for it in _items
    if it["json"].get("active")
]

# Run Once for Each Item
row = _item["json"]
return {"json": {**row, "name_upper": (row.get("name") or "").upper()}}

Node config: {"language": "pythonNative", "mode": "runOnceForAllItems" | "runOnceForEachItem", "pythonCode": "..."} on n8n-nodes-base.code typeVersion 2.

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The only inputs: _items and _item

Mode	Variable	Shape
Run Once for All Items	_items	list of plain dicts {"json": {...}, "pairedItem": {...}}
Run Once for Each Item	_item	one plain dict {"json": {...}, "pairedItem": {...}}

• Each variable exists only in its own mode. _items in each-item mode (or _item in all-items mode) raises NameError.
• Dict access only. it["json"]["name"] or it["json"].get("name"). it.json.name raises AttributeError: 'dict' object has no attribute 'json'.
• No other nodes. There is no _node / $('Node') equivalent. If you need data from another branch, bring it in with Merge first, or read it in JavaScript.
• Webhook payloads are under ["body"]: _items[0]["json"].get("body", {}).get("email").
• Binary data isn't covered here. Read and write binary in JavaScript (see n8n-binary-and-data).
• pairedItem: returning _items / _item keeps it. When you build new dicts and downstream uses $('Node').item, add "pairedItem": {"item": i} to each returned item. That isn't verified on native Python yet, so test-run before relying on it.
• Missing keys: prefer .get(key, default). row["missing"] raises KeyError.