JSON Data Utility: Extract Key-Value Pairs by Index

Extract a key–value pair by index from JSON to fields in n8n

This template takes a JSON object and a row index and returns exactly one key–value pair at that index. It's a handy helper when you only need a single entry from a structured JSON payload (eg, picking one form field for downstream logic).

Who's it for

• Makers who want a quick JSON picker without writing full parsing logic.
• Developers testing API payloads or building proofs of concept .
• Ops/analysts who need to pluck a single field for emails, documents or notifications.

How it works

1. Manual Trigger ( When clicking 'Test workflow' ) starts the flow.
2. Set → Input JSON Node holds your sample payload with:
   • myData : an object of key → value pairs.
   • rowIndex : a 0‑based index indicating which pair to extract.
3. Code (Python) → Find Key‑Value Pair iterates myData and returns [key, value] at rowIndex as result .
4. Set → Key maps result[0] to a field named result .
5. Set → Value maps result[1] to a field named result[1] .
6. The selected key and value are then available to any downstream nodes.

How to set up

1. Open the workflow and select Input JSON Node .
2. Replace the sample with your own JSON:

    {
    "myData": { "name": "Alice", "age": "30", "city": "Paris" },
    "rowIndex": "1"
    }
   

3. Click Execute Workflow . Check the Key and Value nodes for the outputs.

Requirements

• n8n running (cloud or self-hosted).
• Code node (Python) enabled in your n8n version.
• Input payload structure:
  • myData : object with keys/values
  • rowIndex : integer (0‑based)

How to customize

• Pick by key name (instead of index): adjust the Python code to look up a specific key.
• Handle nested objects/arrays : walk or flatten the structure before selecting.
• Change output shape : return { "key": ..., "value": ... } or write directly to next‑node fields.
• Validate inputs : add checks for out‑of‑range rowIndex , non‑object myData , or empty objects.

Add-ons

• Webhook intake : Replace Manual Trigger with a Webhook to accept live JSON.
• Schema guard : Add an If/Function step to ensure myData is an object and rowIndex is numeric.
• Audit log : Append the selected key/value to Google Sheets or a database.

Use Case Examples

• Pull one field from a large API response to include in an email .
• Extract a specific answer from a submission form for conditional routing.
• Read a configuration pair from a settings object to control a downstream step.

Common troubleshooting

Need Help?

If you'd like this to pick by key , handle nested JSON , accept data via Webhook or fully customized to your needs, write to us and we'll adapt the template to your exact use case.