Flatten Nested JSON Arrays in n8n with Code Node

Turn nested JSON into clean lead items in n8n

If your API response includes a nested leads array, this n8n workflow helps you flatten it into one item per lead—while keeping parent metadata and converting each lead’s interests into a ready-to-use CSV string.

What this workflow does

• Manual start: The workflow begins when you run it manually.
• Creates sample nested JSON: It generates a sample payload that includes a source field and a leads array of lead objects.
• Splits leads into individual items: Using the flattening logic, it breaks the nested payload.leads array into separate n8n items—one per lead.
• Adds parent context: Each resulting item is enriched with parent metadata (such as the payload’s source) and the lead’s `array index`.
• Formats interests as CSV: It also builds an interests CSV string for easier downstream processing (for example, for mapping, exporting, or storage).
• Summarizes output: At the end, it reports how many lead items were produced and returns an example output item.

Use cases

• Prepare flattened lead data for database upserts or CRM ingestion.
• Normalize API responses so you can reliably export leads to CSV or feed them into reporting steps.
• Make automation nodes downstream simpler by converting nested arrays into one-item-per-record structures.
• Test and iterate on array-path changes (for example, if your nested array isn’t at payload.leads).

Technical details

• Nodes used: Code node (core flattening/formatting), Sticky Note (workflow documentation), Manual Trigger.
• Setup: Replace the sample data step with your real JSON source (e.g., Webhook or HTTP Request), update the array path (currently payload.leads), and adjust carried-over fields to match your payload structure.

Best for: n8n users, automation engineers, and SaaS operators who need reliable nested JSON array flattening in the Code node.