How to read JSON data in Python script file using n8n node

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1

I’m building an n8n workflow and need help in how to read json data of previous node in python file using n8nnode. Here’s what I’m trying to achieve:

  1. Receive JSON input from a previous node
  2. Process the data in a Python script file
  3. Return modified data as JSON to the next node

Could someone explain:

  • How to properly access incoming JSON data in python file using n8n node?
  • The correct way to return JSON output for downstream nodes?
  • Any best practices or common pitfalls to avoid?

A simple code example showing this data handoff would be extremely helpful!
thanks!

2

Access incoming JSON data in Python

n8n passes data to the Python node through the items variable. Each item is a dictionary with a .json key that holds the actual payload.

for item in items:
data = item[‘json’] # this is your input JSON

  1. Process the data

You can modify the JSON however you want using standard Python syntax.

  1. Return modified JSON

You must return a list of dictionaries with a json key, like so:

return [
{
“json”: modified_data
}
for modified_data in processed_list
]

Simple code
output =

for item in items:
data = item[‘json’]

# Add a new field based on score
data['passed'] = data['score'] >= 50

output.append({"json": data})

return output