Aggregate

Combine many items into one

Overview

Aggregates many items into a single item for downstream output. Supports Individual Fields mode (collect chosen fields into arrays) and All Item Data mode (bundle whole items), with options for flattening lists, keeping null entries, carrying binary data and disabling dot notation.

Category: Core Nodes
Tool Name: aggregate
Version: 1

Appearance: Icon: aggregate | Color: #6366f1

Node Type

Action — processes input items and produces output

Input / Output

Direction	Port(s)
Input	Input
Output	Output, Error

Credentials

This tool does not require any credentials.

Parameters

Parameter	Type	Required	Default	Description
Mode	options	No	individualFields	How to aggregate incoming items.
				Options: individualFields, allItemData
Fields to Aggregate	fixedCollection	No	{ fields: [] }	A list of specific fields to collect from incoming items. Field names support dot notation unless disabled. Used in Individual Fields mode.
— Input Field Name	string	No	—	Field name to collect from each input item. Dot notation is supported unless disabled. Supports expressions.
— Rename Field	boolean	No	false	If enabled, the aggregated list is written to Output Field Name instead.
— Output Field Name	string	No	—	Name of the output field to store the aggregated list (used only if Rename Field is enabled).
Put Output in Field	string	No	data	The field name on the output item that will contain the final array of all items. Supports dot notation unless disabled. Used in All Item Data mode.
Include	options	No	allFields	Which fields from the input items should be included in the aggregated array. Used in All Item Data mode.
				Options: allFields, specifiedFields
Fields To Include	string	No	—	Comma-separated field names (or a JSON array string) to include when Include is Specified Fields. Dot notation is supported unless disabled.
Options	collection	No	{}	Additional settings to refine the output.
— Merge Lists	boolean	No	false	If the field being aggregated is already a list, flatten it into one list rather than a list of lists (Individual Fields mode).
— Keep Missing and Null Values	boolean	No	false	When enabled, missing or null entries are preserved as null. When disabled, they are ignored.
— Include Binaries	boolean	No	false	Include binary data (if present on items) in the aggregated output (All Item Data mode).
— Disable Dot Notation	boolean	No	false	Treat dots in field names as literal characters rather than paths to nested objects.
Max Concurrency	number	No	100	Maximum number of items to hydrate/process concurrently.

Output Data

Everything that reaches this node is collapsed into one output item — however many items arrive, exactly one leaves the main output port. The input JSON does not pass through, and binary data is not forwarded onto the output item itself.

What that item contains depends on Mode:

• Individual Fields — one array per entry in Fields to Aggregate, written under that entry’s Input Field Name, or under its Output Field Name when Rename Field is on. With Merge Lists on, values that are themselves lists are flattened into the collected array rather than nested inside it. Missing and null values are skipped unless Keep Missing and Null Values is on, in which case they are collected as null.
• All Item Data — a single array of item objects under Put Output in Field (data by default). With Include set to allFields each entry is a copy of that item’s JSON; with specifiedFields each entry contains only the fields named in Fields To Include. With Include Binaries on, each entry also carries the source item’s binary data under a binary key.

The shape in All Item Data mode with the default output field:

{
  "data": [
    { "id": 1, "name": "Alice" },
    { "id": 2, "name": "Bob" }
  ]
}

Items that arrive already carrying an upstream error are left out of the aggregate; in errorPort mode they are routed to the Error output port instead.

Reference the result downstream by expression, e.g. {{ $json.data }}.

Usage Examples

• combine all results into one
• merge everything together
• collect all items into a single output
• aggregate the data from all branches
• gather all the processed results

Example Configuration

Basic Individual Fields aggregation:

{
  "type": "aggregate",
  "parameters": {
    "mode": "individualFields",
    "fieldsToAggregate": {
      "fields": [
        {
          "inputFieldName": "name",
          "renameField": false,
          "outputFieldName": ""
        },
        {
          "inputFieldName": "email",
          "renameField": true,
          "outputFieldName": "emailAddresses"
        }
      ]
    },
    "putOutputInField": "aggregatedData"
  }
}

All Item Data with options:

{
  "type": "aggregate",
  "parameters": {
    "mode": "allItemData",
    "putOutputInField": "allItems",
    "include": "specifiedFields",
    "fieldsToInclude": "id,name,status",
    "options": {
      "keepMissingAndNullValues": true,
      "includeBinaries": false,
      "disableDotNotation": false
    }
  }
}

Field aggregation with nested paths:

{
  "type": "aggregate",
  "parameters": {
    "mode": "individualFields",
    "fieldsToAggregate": {
      "fields": [
        {
          "inputFieldName": "user.profile.name",
          "renameField": true,
          "outputFieldName": "userNames"
        },
        {
          "inputFieldName": "metrics.score",
          "renameField": false,
          "outputFieldName": ""
        }
      ]
    },
    "options": {
      "mergeLists": true,
      "keepMissingAndNullValues": false
    }
  }
}

When aggregating user information from multiple sources:

{
  "type": "aggregate",
  "parameters": {
    "mode": "individualFields",
    "fieldsToAggregate": {
      "fields": [
        {
          "inputFieldName": "firstName",
          "renameField": false,
          "outputFieldName": ""
        },
        {
          "inputFieldName": "lastName",
          "renameField": false,
          "outputFieldName": ""
        },
        {
          "inputFieldName": "contactInfo.email",
          "renameField": true,
          "outputFieldName": "emails"
        }
      ]
    },
    "putOutputInField": "userData",
    "options": {
      "keepMissingAndNullValues": false
    }
  }
}

When you need all data from each item preserved:

{
  "type": "aggregate",
  "parameters": {
    "mode": "allItemData",
    "putOutputInField": "completeDataset",
    "include": "allFields",
    "options": {
      "includeBinaries": true,
      "keepMissingAndNullValues": true
    },
    "maxConcurrency": 5
  }
}

When working with nested arrays that need flattening:

{
  "type": "aggregate",
  "parameters": {
    "mode": "individualFields",
    "fieldsToAggregate": {
      "fields": [
        {
          "inputFieldName": "tags",
          "renameField": true,
          "outputFieldName": "allTags"
        },
        {
          "inputFieldName": "categories",
          "renameField": false,
          "outputFieldName": ""
        }
      ]
    },
    "options": {
      "mergeLists": true,
      "keepMissingAndNullValues": false
    }
  }
}

Error Handling

Mode	Behavior
stop	Halts workflow on first error
continue	Skips failed items, passes successful ones through
errorPort	Routes failed items to Error output port

Tips

Collects multiple input items into a single output item, either by gathering specific fields into arrays or bundling all items together. Use when you need to consolidate results from a previous step before final output or further processing. Produces one item containing arrays or grouped data from all input items.