Sending automated alerts is one of the best ways to keep a team informed, but there is a fine line between “staying updated” and “getting spammed.” If your workflow sends 40 individual emails for 40 pending orders, you aren’t helping your team—you’re clogging their inbox.
In this lesson by GenAI Unplugged, we learn how to use the Aggregate Node to combine multiple data entries into a single, clean summary [00:06].
The Problem: Multi-Item Iteration
In n8n, every node executes for every single item that enters it. If 41 pending orders come out of a Switch node, the “Send Email” node will run 41 times, sending 41 separate emails [08:21]. This is overwhelming for customer service and inefficient for your system.
The Solution: The Aggregate Node
The Aggregate Node acts as a funnel. It takes a list of multiple items and merges them into a single data entry [00:13].
How to Configure It:
- Select Fields to Aggregate: Choose the specific data point you want to collect. In this case, we select the
orderID[06:09]. - Merge into One Item: Instead of 41 items with one Order ID each, n8n creates one item containing a list of all 41 Order IDs [08:07].
- Summarize: You can now connect this single output to an email or Slack node.
Real-World Use Case: The Pending Order Summary
Instead of a service team receiving a notification for every line item, they receive one email that looks like this:
- Subject: Pending Orders from Today – [Current Date] [08:46]
- Body: “Please connect with customers for the following orders: OD001, OD002, OD003…” [09:27]
By grouping these items, you’ve turned 41 potential distractions into a single, actionable task for the team [10:02].
Beyond Basic Aggregation
While the tutorial focuses on collecting IDs, the Aggregate Node is also useful for:
- Summarizing Values: Totaling the price of all orders processed in a day.
- Grouping: Creating collections based on status (e.g., all “Refunded” orders in one list).
- Unique Lists: Combining email addresses into a single list to avoid sending duplicate marketing materials [00:21].
A Sneak Peek at the Next Step
Even with the Aggregate Node, you might still see duplicates in your list (e.g., “OD001” appearing three times because the customer ordered three products) [10:46]. To fix this, you’ll need to pair the Aggregate Node with the Remove Duplicates Node, which we cover in the next part of this series.
Watch the full video tutorial here: How to Use Aggregate Node in n8n
