SubWorkflow sub-workflow

When to Use

• Modular workflow design: Break a 50-node monolithic workflow into reusable sub-workflows — for example, extract a "Send Invoice" sub-workflow that is called from both the "New Order" and "Subscription Renewal" parent workflows without duplicating any steps.
• Shared processing logic: Multiple parent workflows invoke the same "Validate Customer" sub-workflow rather than embedding identical validation logic in each parent. A fix in the child propagates everywhere automatically.
• Multi-stage onboarding: A parent "Employee Onboarding" workflow sequentially calls sub-workflows for IT provisioning, HR paperwork, and Slack workspace setup — each sub-workflow is independently testable and replaceable.
• Conditional delegation: Route to different sub-workflows based on a runtime condition — invoke "Standard Approval" or "Expedited Approval" sub-workflow based on the request amount, keeping the decision logic in the parent and the execution logic in the children.
• Error isolation: Wrap risky external-API calls in a dedicated sub-workflow so the parent can handle success and failure cleanly via ports, without embedding try/catch logic at the top level.

Configuration

Sample Configuration

Static child workflow ID

{
  "sub_workflow_id": 42,
  "sub_workflow_version_id": 3
}

Dynamic child workflow ID from a workflow variable

{
  "sub_workflow_id": "{{ $var.approval_workflow_id }}",
  "sub_workflow_version_id": 1
}

Child workflow ID resolved from InputData (no static config needed)

{
  "sub_workflow_version_id": 1
}
// sub_workflow_id provided in InputData by the preceding node

Validation Errors

Output / Execution Ports

success Port — Output Fields

error Port — Output Fields

Sample Output

success port output (available via $output.launchSetup)

{
  "subworkflow": {
    "result": {
      "userId": "u_88142",
      "email": "jane.doe@acme.com",
      "provisionedAt": "2026-05-26T09:14:02Z"
    },
    "provisioning": {
      "adAccountCreated": true,
      "adAccountId": "AD-88142"
    },
    "slackInvite": {
      "channelId": "C04XYZABC",
      "inviteSent": true
    }
  }
}

error port output (available via $output.launchSetup)

{
  "error": {
    "code": "CHILD_WORKFLOW_FAILED",
    "message": "Child workflow 42 failed at node 'validateLicense' with: License key is expired."
  }
}

Expression Reference

Node Policies & GuardRails

Examples

Example 1 — Reusable Customer Validation Sub-Workflow

An order processing parent workflow calls a shared "Validate Customer" child workflow before proceeding. The child checks account status, credit limit, and region eligibility. The parent branches on success or failure without duplicating any validation logic.

WebhookTrigger  [key: "orderReceived"]
  (POST /orders/new)
  └─► SubWorkflow  [key: "validateCustomer"]
        sub_workflow_id: 18        // "Validate Customer" workflow
        sub_workflow_version_id: 2
        ├─► success ──► IfCondition  [key: "checkCreditLimit"]
        │                 Condition: {{ $output.validateCustomer.subworkflow.result.creditApproved == true }}
        │                 ├─► true  ──► [proceed to fulfillment]
        │                 └─► false ──► StopWorkflow (status: cancelled, message: "Credit limit exceeded")
        └─► error ──► StopWorkflow (status: failed, message: {{ $output.validateCustomer.error.message }})

Example 2 — Sequential Onboarding Sub-Workflows

A parent "Employee Onboarding" workflow calls three sub-workflows in sequence: IT provisioning, HR paperwork, and Slack setup. Each sub-workflow is independently owned by a different team. The parent orchestrates the sequence and handles failures at each stage.

FormTrigger  [key: "hrFormSubmitted"]
  └─► SubWorkflow  [key: "itProvisioning"]
        sub_workflow_id: {{ $var.it_provisioning_workflow_id }}
        ├─► success ──► SubWorkflow  [key: "hrPaperwork"]
        │                 sub_workflow_id: {{ $var.hr_paperwork_workflow_id }}
        │                 ├─► success ──► SubWorkflow  [key: "slackSetup"]
        │                 │                 sub_workflow_id: {{ $var.slack_setup_workflow_id }}
        │                 │                 ├─► success ──► EmailSmtp  (welcome email to new employee)
        │                 │                 └─► error   ──► Slack  (alert: Slack setup failed for {{ $json.employeeName }})
        │                 └─► error ──► Slack  (alert: HR paperwork failed)
        └─► error ──► Slack  (alert: IT provisioning failed — manual intervention required)

Example 3 — Dynamic Sub-Workflow Dispatch

An approval routing workflow selects which approval sub-workflow to call based on the request amount. Small requests go to a fast-track single-approver workflow; large requests go to a multi-stage committee approval workflow. The parent does not embed any approval logic itself.

WebhookTrigger  [key: "approvalRequest"]
  └─► IfCondition  [key: "routeByAmount"]
        Condition: {{ $json.amount > 10000 }}
        ├─► true ──► VariableAssignment  [key: "setCommitteeId"]
        │              approval_workflow_id = 77   // Committee Approval workflow
        │              └─► SubWorkflow  [key: "runApproval"]
        │                    sub_workflow_id: {{ $var.approval_workflow_id }}
        │                    ├─► success ──► HttpRequest  (POST /orders/{{ $json.orderId }}/approve)
        │                    └─► error   ──► StopWorkflow (status: failed, message: "Approval process failed")
        └─► false ──► VariableAssignment  [key: "setFastTrackId"]
                       approval_workflow_id = 31  // Fast-Track Approval workflow
                       └─► SubWorkflow  [key: "runApproval"]
                             (same wiring as above)