Examples

Example 1: Order Notification — Aggregate Channel Results

Simultaneously send email, SMS, and Slack notifications. After the Join, check how many channels succeeded and route accordingly.

// Parallel Fork
{
  "node_type": "ParallelFork",
  "node_id": "NotifyChannels",
  "config": { "fail_fast": false },
  "connections": {
    "success": ["SendEmail", "SendSms", "PostSlack"]
  }
}

// Parallel Join (no config needed)
{
  "node_type": "ParallelJoin",
  "node_id": "WaitForNotifications"
}

// After Join success port fires:
// $var.lane_success_count  → 3 (if all succeeded)
// $var.lane_0_emailSent    → true
// $var.lane_1_smsSent      → true
// $var.lane_2_slackPosted  → true

// Downstream IfCondition:
// "$var.lane_success_count >= 1"  → at least one channel worked → proceed
// "$var.lane_success_count === 0" → all channels failed → escalate

Expected outcome: Even if one channel fails, the workflow proceeds if at least one notification was delivered. All channel statuses are available for the audit log.

Example 2: Customer Enrichment — Merge All API Results

Call three enrichment APIs concurrently, then merge their results into a unified customer risk profile. All three are required, so fail_fast is enabled.

// Parallel Fork
{
  "node_type": "ParallelFork",
  "node_id": "EnrichCustomer",
  "config": { "fail_fast": true },
  "connections": {
    "success": [
      "CallCreditAPI",     // lane 0: sets creditScore
      "CallFraudAPI",      // lane 1: sets riskLevel
      "CallLoyaltyAPI"     // lane 2: sets loyaltyTier
    ]
  }
}

// After Parallel Join fires success:
// $var.lane_0_creditScore  → 742
// $var.lane_1_riskLevel    → "low"
// $var.lane_2_loyaltyTier  → "gold"

// Downstream SetVariable node creates:
// customerProfile = {
//   creditScore: $var.lane_0_creditScore,
//   riskLevel:   $var.lane_1_riskLevel,
//   loyaltyTier: $var.lane_2_loyaltyTier
// }

Expected outcome: All three API results are merged into a single customerProfile object. If any API fails, the workflow routes to an error handler immediately (fail_fast), preventing a partial profile from being used.

Example 3: Parallel Validation — Loan Application Checks

Run four validation checks in parallel for a loan application. After the Join, confirm all four passed before approving.

// Parallel Fork
{
  "node_type": "ParallelFork",
  "node_id": "RunValidations",
  "config": { "fail_fast": false },
  "connections": {
    "success": [
      "CheckCreditHistory",    // lane 0: sets creditPassed
      "VerifyIdentity",        // lane 1: sets identityPassed
      "VerifyIncome",          // lane 2: sets incomePassed
      "VerifyAddress"          // lane 3: sets addressPassed
    ]
  }
}

// After Parallel Join fires:
// lane_success_count = 4 (if all pass)
// $var.lane_0_creditPassed   → true
// $var.lane_1_identityPassed → true
// $var.lane_2_incomePassed   → true
// $var.lane_3_addressPassed  → false  ← address check failed

// Downstream IfCondition:
// "$var.lane_0_creditPassed && $var.lane_1_identityPassed &&
//  $var.lane_2_incomePassed && $var.lane_3_addressPassed"
//   true:  → ApproveLoanApplication
//   false: → RouteToHumanReview (with specific failed checks identified)

Expected outcome: All four checks run concurrently. The Join provides individual pass/fail for each check. The downstream node identifies exactly which checks failed (address in this case) and routes the application to human review with the failure details populated.

Example 4: Document Generation — Collect All Document URLs

Generate four documents in parallel and collect all their storage URLs into a single array after the Join. The array is used to attach all documents to the outbound email.

// Parallel Fork
{
  "node_type": "ParallelFork",
  "node_id": "GenerateDocuments",
  "config": { "fail_fast": false },
  "connections": {
    "success": [
      "GenerateInvoice",        // lane 0: sets documentUrl
      "GenerateShippingLabel",  // lane 1: sets documentUrl
      "GeneratePickList",       // lane 2: sets documentUrl
      "GenerateRemittance"      // lane 3: sets documentUrl
    ]
  }
}

// After Parallel Join fires:
// lane_outputs[0].documentUrl → "https://storage.../invoice-001.pdf"
// lane_outputs[1].documentUrl → "https://storage.../label-001.pdf"
// lane_outputs[2].documentUrl → "https://storage.../picklist-001.pdf"
// lane_outputs[3].documentUrl → "https://storage.../remittance-001.pdf"

// SetVariable:
// allDocumentUrls = lane_outputs.map(l => l.documentUrl)
// → ["https://.../invoice-001.pdf", "https://.../label-001.pdf", ...]

// SendDispatchEmail uses: $var.allDocumentUrls as attachment list

Expected outcome: All four documents are generated concurrently. The Join provides the lane_outputs array, from which all document URLs are extracted into a flat array. The dispatch email is sent with all four documents attached in a single operation.