Modular & Lambda Workflows

In Agentic Workflow Studio you can have one workflow call another workflow—creating modular, reusable components of automation.
This helps you break large automations into smaller pieces, reuse logic, and keep workflows easier to manage.
(This aligns with the sub-workflow concept from n8n docs)

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Why use modular (lambda) workflows

• Reuse logic across different workflows: for example, a “Normalize Data” or “Send Report” module.
• Keep individual workflows smaller, faster, and easier to maintain.
• Update a sub-workflow once and have multiple parent workflows benefit automatically.

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How it works

Step 1: Create the sub-workflow

• Create a new workflow to act as a reusable piece.
• At the start of it, include an Execute Sub-workflow Trigger node (also called “When executed by another workflow”).
• Define its input fields or structure in the trigger configuration.
• Build the internal logic, test and save the sub-workflow.

Step 2: Call the sub-workflow from a parent workflow

• In the parent workflow, use the Execute Workflow (or “Execute Sub-workflow”) node.
• Select the workflow to call (or reference it via an ID or URL).
• Map input data from the parent into the sub-workflow’s input format.
• Configure whether the parent waits for a result or continues asynchronously.

How data passes between workflows

sequenceDiagram
  participant Parent as Parent Workflow
  participant Execute as ExecuteWorkflow Node
  participant SubTrigger as Sub-workflow Trigger
  participant SubLogic as Sub-workflow Logic
  participant ParentResume as Parent Workflow

  Parent->>Execute: Send input data
  Execute->>SubTrigger: Trigger sub-workflow
  SubTrigger->>SubLogic: Process data
  SubLogic-->>SubTrigger: Return processed results
  SubTrigger-->>Execute: Output back to parent
  Execute-->>ParentResume: Parent continues with results

In this sequence:

• The parent workflow sends data into the sub-workflow trigger.
• The sub-workflow processes data and returns output.
• The parent workflow resumes with the returned output. This ensures you can define clear input and output formats via the “Lambda Input” (trigger) and “Lambda Output” (last step) nodes, making modules predictable and reusable.

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Best practices

• Name sub-workflows descriptively (e.g., Normalize Data, Send Monthly Report).
• Document inputs and outputs: use Sticky Notes (see Sticky Notes) on your workflows.
• After import or copy of workflows, test parent workflows to confirm integration.
• Avoid circular calls (Workflow A calls B, and B calls A) unless intentionally designed.
• Keep sub-workflows focused on one task only: modular and reusable logic is easier to track and maintain.

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When not to use modular workflows

• The logic is very simple and used only once—modularizing may add unnecessary overhead.
• Interdependencies between actions are tightly coupled and harder to break out.
• Latency is a concern: if the parent must wait for a sub workflow that takes long, reconsider splitting. In such cases, you may prefer simpler patterns like Splitting workflows or Looping & Iteration.