Keep both lists after Aggregate.

See the output-name collision

Two different input paths can resolve to the same output name. In Aggregate v1, customer.name and supplier.name can both become name. A green execution status alone does not tell you whether both lists survived.

[
  { "customer": { "name": "Alice" }, "supplier": { "name": "Acme" } },
  { "customer": { "name": "Bob" }, "supplier": { "name": "Beta" } }
]

{ "name": ["Acme", "Beta"] }

This is a dated, controlled result for that release and configuration. Other versions or settings may behave differently. Explicitly assigning the same alias twice produced an error in the same tests; a duplicate does not always mean a silent overwrite.

Check saved exports locally

The free audit scans saved workflow JSON for static duplicate output names. It reads the files on your computer and prints a JSON report. It does not upload, edit or execute workflows, evaluate expressions, or need a Keptick account.

1. Export the workflows you are authorised to inspect. Keep the original files local.
2. Save the script from this page. Use Node.js 20 or later.
3. Run it against one workflow export, a batch export, or several files:

node n8n-aggregate-output-audit.mjs workflow.json
node n8n-aggregate-output-audit.mjs workflow.json another-workflow.json

The report identifies the file, workflow, node and field indexes, node name, input fields and resolved output name. Indexes start at zero. Review the report before sharing it; names in your export may be confidential.

Read the result and its coverage

An exit of zero does not certify the workflow. The audit covers Aggregate typeVersion: 1 in Individual Fields mode. Disabled nodes and All Item Data nodes are counted separately and skipped.

Active expressions, unknown versions, invalid configurations and nested output-path interactions require manual review. Runtime input shape, missing values, execution paths and other node types are outside this check.

Give the outputs distinct names

On a copy of a flagged workflow, enable Rename Field and choose distinct output names such as customers and suppliers. Run known fictional inputs and inspect both output lists and every downstream reference that uses the old names.

{
  "customers": ["Alice", "Bob"],
  "suppliers": ["Acme", "Beta"]
}

A stored alias with Rename Field off is inactive; the audit ignores it, as the tested runtime did. An empty active alias can fall back to the input path's final segment.

Do not switch on Disable Dot Notation merely to silence a warning. It reads literal dotted keys and changes the meaning of nested input paths. Choose the configuration that matches your actual data.

Separate an export check from live monitoring

This audit examines saved configuration. It does not repair n8n or add a live monitor.

For recurring work, separately check what the workflow actually produced. Keptick can evaluate outcome receipts against an expected count and flag missing runs. Your workflow must send those receipts. A count alone does not prove that the correct customer records survived an Aggregate step.

Use the record-reconciliation example when you need to compare expected and completed IDs. The monitoring setup guide explains the separate live-monitor workflow and free allowance.