n8n Aggregate nodeConfigure Aggregate in n8n.
The n8n Aggregate node turns many items into a single one. It reads a field across every item that reaches it and writes the values back as one list. Six parameters decide which fields travel, how lists and files behave, and what happens to empty values.
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What does the n8n Aggregate node do to your items?
Most nodes in n8n run once per item, and that is usually what you want. It stops being what you want the moment you need a summary. The Aggregate node takes the separate items reaching it and groups them, or portions of them, into individual items. Its own description says it plainly: combine a field from many items into a list in a single item.
Think of a workflow that reads a batch of rows from Google Sheets. Without Aggregate, the node after it fires once per row, and forty rows mean forty runs. Put Aggregate in between, gather the field you care about, and the rest of the workflow runs once on one item holding one list.
Three results come up again and again. The first is the single message: pull {{ $json.email }} out of every row, aggregate it, and send one digest through Gmail instead of one message per row. The second is the clean payload: aggregate all item data into a field you name with Put Output in Field, keep only the columns you want with Include, and hand a tidy list to whatever comes next. The third is the file bundle: switch Include Binaries on so attachments carried by the incoming items land in the aggregated item too, with Keep Only Unique Binaries to drop the copies.
Pick a different node when the shape of the problem is different. Merge joins two branches of a workflow; Aggregate works on one stream of items arriving at one input. Edit Fields (Set) renames or builds fields item by item and leaves the count alone. Aggregate is the one that changes how many items leave.
The limits are worth knowing before you build on it. The node is at version 1, so what the panel shows is what it does: two aggregation modes and the options listed below, nothing else. Three of those options, Disable Dot Notation, Merge Lists and Keep Missing And Null Values, only appear once you select Individual Fields. And Aggregate does not start anything: like every core node it needs a trigger in front of it, a Schedule Trigger, a Webhook, or the trigger of a tool. If you want the wider picture on the platform, the n8n review covers it.
Which Aggregate parameters matter, and when?
The Aggregate node has 6 parameters. For each one: the node as you configure it in n8n, what the parameter changes, and our field notes.
Aggregate
aggregateWhat you see in n8n
Notes & use cases
This is the choice that shapes the whole panel. Pick aggregateIndividualFields to carry named fields across as lists, or aggregateAllItemData to drop every incoming item whole into one list under a field name you choose.
Key parameters
- Fields To Aggregate: one row per input field you want gathered, added with Add Field To Aggregate.
- Put Output in Field: the name of the output field the data goes into when you aggregate all item data.
- Include:
allFields, orspecifiedFieldswith Fields To Include, orallFieldsExceptwith Fields To Exclude, both written as a comma separated list such asemail, name.
{{ $json.email }} from a search result into one list before a single send.Disable Dot Notation
options.disableDotNotationWhat you see in n8n
Notes & use cases
A dot in a field name is ambiguous. By default n8n reads parent.child as a path into a nested object, which breaks the day a field is literally called that. This toggle removes the ambiguity, and it shows up once Individual Fields is selected.
Key parameters
- Disable Dot Notation: on, referencing child fields with
parent.childin the field name is disallowed and the name is matched as written.
Merge Lists
options.mergeListsWhat you see in n8n
Notes & use cases
Aggregating a field that already holds a list gives you a list of lists, one entry per incoming item. Rarely what the next node expects. Turn this on and the output collapses into a single flat list instead.
Key parameters
- Merge Lists: on, the output is merged into a single flat list rather than a list of lists, when the field to aggregate is itself a list.
Include Binaries
options.includeBinariesWhat you see in n8n
Notes & use cases
Files ride along with items as binary data, separately from the JSON fields. Aggregate leaves them behind unless you ask for them, so a PDF attached upstream disappears at this step. Switch the toggle on and the files travel into the new item.
Key parameters
- Include Binaries: on, the binary data of the incoming items is included in the new item.
Keep Only Unique Binaries
options.keepOnlyUniqueWhat you see in n8n
Notes & use cases
Duplicate files pile up fast when several items happen to carry the same document. This toggle filters them, comparing mime types, file types, file sizes and file extensions to decide what counts as the same file.
Key parameters
- Keep Only Unique Binaries: on, only unique binaries are kept, compared on mime types, file types, file sizes and file extensions.
Keep Missing And Null Values
options.keepMissingWhat you see in n8n
Notes & use cases
Empty values simply vanish from the aggregated list by default, which quietly changes its length. That matters whenever position is meaningful, for instance when two aggregated lists are read side by side. Turning this on preserves the gaps.
Key parameters
- Keep Missing And Null Values: on, a null entry is added to the aggregated list whenever the input value is missing or null.
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Aggregate in n8n: the questions that come next
01Is the n8n Aggregate node free to use?
02What credentials does the Aggregate node need?
03What are the limits of the Aggregate node?
04Aggregate or Merge: which one should you pick?
05n8n or Make for this kind of batching?
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