Modular & Lambda Workflows

Sometimes you’ll want to reuse the same set of steps in multiple workflows.

Modular (lambda) workflows let one workflow run another workflow.

This helps you:

• Keep workflows smaller and easier to understand
• Reuse the same “module” in multiple places
• Update the module once instead of updating many workflows

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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 reusable workflow

• Create a new workflow to act as a reusable piece.
• Set it up to accept input from another workflow.
• Build the internal logic, test and save the sub-workflow.

Step 2: Call it from a parent workflow

• In the parent workflow, add a node that calls the other workflow.
• Choose which workflow to run.
• Pass in the data you want the sub-workflow to process.
• Use the output as the input for the next step.

Node reference: Lambda Workflow.

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. To keep things predictable, decide what input fields the sub-workflow expects and what output it returns.

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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.