AutomationFlowsGeneral › Parallel Sub-Workflow Execution Pattern

Parallel Sub-Workflow Execution Pattern

Original n8n title: Pattern for Parallel Sub Workflow Execution Followed by Wait for All Loop

Pattern For Parallel Sub Workflow Execution Followed By Wait For All Loop. Uses manualTrigger, splitInBatches, httpRequest, respondToWebhook. Event-driven trigger; 18 nodes.

Event trigger★★★★☆ complexity18 nodesHTTP Request
General Trigger: Event Nodes: 18 Complexity: ★★★★☆ Added:

The workflow JSON

Copy or download the full n8n JSON below. Paste it into a new n8n workflow, add your credentials, activate. Full import guide →

Download .json
{
  "nodes": [
    {
      "id": "0d911b91-bb9a-4177-8cd5-12ddddf1bc61",
      "name": "When clicking \u2018Test workflow\u2019",
      "type": "n8n-nodes-base.manualTrigger",
      "position": [
        580,
        405
      ],
      "parameters": {},
      "typeVersion": 1
    },
    {
      "id": "d13f78f7-4093-435f-8b38-722f4a5c7a1f",
      "name": "Loop Over Items",
      "type": "n8n-nodes-base.splitInBatches",
      "position": [
        1020,
        405
      ],
      "parameters": {
        "options": {}
      },
      "typeVersion": 3
    },
    {
      "id": "97d26220-a85f-4c40-b97c-b36f2d235776",
      "name": "Webhook Callback Wait",
      "type": "n8n-nodes-base.wait",
      "position": [
        1720,
        445
      ],
      "parameters": {
        "resume": "webhook",
        "options": {},
        "httpMethod": "POST",
        "responseMode": "responseNode"
      },
      "typeVersion": 1.1
    },
    {
      "id": "ee02d5cb-8151-4b24-a630-77a677b1434a",
      "name": "Update finishedSet",
      "type": "n8n-nodes-base.code",
      "position": [
        1940,
        445
      ],
      "parameters": {
        "jsCode": "let json = $('If All Finished').first().json;\nif (!json.finishedSet) json.finishedSet = [];\nlet finishedItemId = $('Webhook Callback Wait').item.json.body.finishedItemId;\nif (!json.finishedSet[finishedItemId]) json.finishedSet.push(finishedItemId);\nreturn [json];"
      },
      "typeVersion": 2
    },
    {
      "id": "09f1cf3f-9e32-43f2-9e57-d7a33970dac4",
      "name": "Initialize finishedSet",
      "type": "n8n-nodes-base.set",
      "position": [
        1240,
        285
      ],
      "parameters": {
        "options": {},
        "assignments": {
          "assignments": [
            {
              "id": "193ab8f1-0e23-491c-914e-b8b26b0160f7",
              "name": "finishedSet",
              "type": "array",
              "value": "[]"
            }
          ]
        }
      },
      "executeOnce": true,
      "typeVersion": 3.4
    },
    {
      "id": "105d8f64-8ade-4e02-8722-587a35f2b046",
      "name": "Simulate Multi-Item for Parallel Processing",
      "type": "n8n-nodes-base.code",
      "position": [
        780,
        405
      ],
      "parameters": {
        "jsCode": "return [\n  {requestId: 'req4567'},\n  {requestId: 'req8765'},\n  {requestId: 'req1234'}\n];"
      },
      "typeVersion": 2
    },
    {
      "id": "c5f72fa0-693e-4134-910f-8fd0767861d1",
      "name": "If All Finished",
      "type": "n8n-nodes-base.if",
      "position": [
        1460,
        285
      ],
      "parameters": {
        "options": {},
        "conditions": {
          "options": {
            "version": 1,
            "leftValue": "",
            "caseSensitive": true,
            "typeValidation": "strict"
          },
          "combinator": "and",
          "conditions": [
            {
              "id": "385c3149-3623-4dd2-9022-770c32f82421",
              "operator": {
                "type": "number",
                "operation": "gte"
              },
              "leftValue": "={{ $json.finishedSet.length }}",
              "rightValue": "={{ $('Simulate Multi-Item for Parallel Processing').all().length }}"
            }
          ]
        }
      },
      "typeVersion": 2
    },
    {
      "id": "20d16393-8573-4cc1-adc0-034f0f1def70",
      "name": "Start Sub-Workflow via Webhook",
      "type": "n8n-nodes-base.httpRequest",
      "position": [
        1180,
        645
      ],
      "parameters": {
        "url": "={{ $env.WEBHOOK_URL }}/webhook/parallel-subworkflow-target",
        "method": "POST",
        "options": {},
        "sendBody": true,
        "sendHeaders": true,
        "bodyParameters": {
          "parameters": [
            {
              "name": "requestItemId",
              "value": "={{ $json.requestId }}"
            }
          ]
        },
        "headerParameters": {
          "parameters": [
            {
              "name": "callbackurl",
              "value": "={{ $execution.resumeUrl }}"
            }
          ]
        }
      },
      "typeVersion": 4.2
    },
    {
      "id": "4ad48520-39b3-4016-a6a9-dd789c079e08",
      "name": "Acknowledge Finished",
      "type": "n8n-nodes-base.respondToWebhook",
      "position": [
        1780,
        665
      ],
      "parameters": {
        "options": {}
      },
      "typeVersion": 1.1
    },
    {
      "id": "ad1018a1-3b9d-4613-b23f-136763a514ba",
      "name": "Sticky Note",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        720,
        605
      ],
      "parameters": {
        "color": 3,
        "width": 390,
        "height": 109,
        "content": "### Start Multiple Sub-Workflows Asynchronously\n* Note: Callback/Webhook \"internal\" Base-URL should be configured in the n8n instance to reference the k8s service name and internal port."
      },
      "typeVersion": 1
    },
    {
      "id": "f4171d39-8bfe-4e3a-9b94-87d969abda2d",
      "name": "Sticky Note1",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        1740,
        365
      ],
      "parameters": {
        "color": 3,
        "width": 283,
        "height": 80,
        "content": "### Pseudo-Synchronously Wait for All Sub-Workflows to finish"
      },
      "typeVersion": 1
    },
    {
      "id": "98657cd3-968c-4d66-aea0-4e3180f8508f",
      "name": "Continue Workflow (noop)",
      "type": "n8n-nodes-base.noOp",
      "position": [
        1780,
        205
      ],
      "parameters": {},
      "typeVersion": 1
    },
    {
      "id": "5a9518ea-456e-4975-bf6f-71bf9ed0a6e1",
      "name": "Sticky Note3",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        540,
        180
      ],
      "parameters": {
        "width": 1577.931818181817,
        "height": 684.1818181818179,
        "content": "## Main/Parent Workflow\n* This starts multiple executions of the sub-workflow in parallel and then loops until they all report back."
      },
      "typeVersion": 1
    },
    {
      "id": "13ad3423-c3bf-4144-b76d-03daa8877bed",
      "name": "Sticky Note2",
      "type": "n8n-nodes-base.stickyNote",
      "position": [
        560,
        900
      ],
      "parameters": {
        "width": 1477.331211260329,
        "height": 189.2194473140495,
        "content": "### Sub-Workflow\n**Cut/Paste this into a separate workflow, and activate it!!!**"
      },
      "typeVersion": 1
    },
    {
      "id": "e92865b0-b3e9-4195-ae16-5c199875a04b",
      "name": "Wait",
      "type": "n8n-nodes-base.wait",
      "position": [
        1440,
        940
      ],
      "parameters": {},
      "typeVersion": 1.1
    },
    {
      "id": "710456c8-394d-4c45-8d8e-16e0a4095dc3",
      "name": "Call Resume on Parent Workflow",
      "type": "n8n-nodes-base.httpRequest",
      "notes": "The callback resumes the parent workflow and reports which item finished.  There could be a race condition if the parent workflow was just resumed by a different sub-workflow but hasn't entered a webhook-wait again yet.  The delay and retry mitigates for the possibility that multiple subtasks complete and call back at once.",
      "position": [
        1660,
        940
      ],
      "parameters": {
        "url": "={{ $('Webhook').item.json.headers.callbackurl }}",
        "method": "POST",
        "options": {},
        "sendBody": true,
        "bodyParameters": {
          "parameters": [
            {
              "name": "finishedItemId",
              "value": "={{ $('Webhook').item.json.body.requestItemId }}"
            }
          ]
        }
      },
      "retryOnFail": true,
      "typeVersion": 4.2,
      "waitBetweenTries": 3000
    },
    {
      "id": "2ee41b1a-89f0-4d2f-b2ff-74aef5baaa70",
      "name": "Respond to Webhook",
      "type": "n8n-nodes-base.respondToWebhook",
      "position": [
        1220,
        940
      ],
      "parameters": {
        "options": {},
        "respondWith": "json",
        "responseBody": "={{ \n{\n  \"finishedItemId\": $json.body.requestItemId\n}\n}}"
      },
      "typeVersion": 1.1
    },
    {
      "id": "04445a9a-61f9-468e-8589-3eeb403f2553",
      "name": "Webhook",
      "type": "n8n-nodes-base.webhook",
      "position": [
        1000,
        940
      ],
      "parameters": {
        "path": "parallel-subworkflow-target",
        "options": {},
        "httpMethod": "POST",
        "responseMode": "responseNode"
      },
      "typeVersion": 2
    }
  ],
  "connections": {
    "Wait": {
      "main": [
        [
          {
            "node": "Call Resume on Parent Workflow",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Webhook": {
      "main": [
        [
          {
            "node": "Respond to Webhook",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "If All Finished": {
      "main": [
        [
          {
            "node": "Continue Workflow (noop)",
            "type": "main",
            "index": 0
          }
        ],
        [
          {
            "node": "Webhook Callback Wait",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Loop Over Items": {
      "main": [
        [
          {
            "node": "Initialize finishedSet",
            "type": "main",
            "index": 0
          }
        ],
        [
          {
            "node": "Start Sub-Workflow via Webhook",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Respond to Webhook": {
      "main": [
        [
          {
            "node": "Wait",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Update finishedSet": {
      "main": [
        [
          {
            "node": "Acknowledge Finished",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Acknowledge Finished": {
      "main": [
        [
          {
            "node": "If All Finished",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Webhook Callback Wait": {
      "main": [
        [
          {
            "node": "Update finishedSet",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Initialize finishedSet": {
      "main": [
        [
          {
            "node": "If All Finished",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Start Sub-Workflow via Webhook": {
      "main": [
        [
          {
            "node": "Loop Over Items",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "When clicking \u2018Test workflow\u2019": {
      "main": [
        [
          {
            "node": "Simulate Multi-Item for Parallel Processing",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "Simulate Multi-Item for Parallel Processing": {
      "main": [
        [
          {
            "node": "Loop Over Items",
            "type": "main",
            "index": 0
          }
        ]
      ]
    }
  }
}
Pro

For the full experience including quality scoring and batch install features for each workflow upgrade to Pro

How this works

This pattern enables you to process multiple items simultaneously through sub-workflows, drastically reducing overall execution time for tasks like batch data updates or parallel API calls. It's ideal for users handling high-volume operations who need efficient, scalable automation without sequential bottlenecks. The key step involves triggering sub-workflows via HTTP requests in parallel using splitInBatches, then employing a wait mechanism to synchronise results until all complete, ensuring reliable aggregation of outcomes.

Use this when dealing with independent tasks that benefit from concurrency, such as syncing contacts across multiple services or generating reports from diverse sources. Avoid it for sequential dependencies where order matters, or low-volume jobs that don't justify the setup complexity. Common variations include adapting the wait loop for partial failures or integrating with specific APIs like Google Sheets for data collection.

About this workflow

Pattern For Parallel Sub Workflow Execution Followed By Wait For All Loop. Uses manualTrigger, splitInBatches, httpRequest, respondToWebhook. Event-driven trigger; 18 nodes.

Source: https://github.com/Zie619/n8n-workflows — original creator credit. Request a take-down →

More General workflows → · Browse all categories →

Related workflows

Workflows that share integrations, category, or trigger type with this one. All free to copy and import.

General

Kv Cloudflare Key Value Database Full Api Integration Workflow. Uses stickyNote, httpRequest, manualTrigger. Event-driven trigger; 47 nodes.

HTTP Request
General

Reputation Engine — Site Refresh. Uses httpRequest, executeWorkflowTrigger. Event-driven trigger; 35 nodes.

HTTP Request, Execute Workflow Trigger
General

Reputation Engine — Content Generator. Uses httpRequest. Event-driven trigger; 30 nodes.

HTTP Request
General

PRECALL. Uses executeWorkflowTrigger, httpRequest. Event-driven trigger; 23 nodes.

Execute Workflow Trigger, HTTP Request
General

Blog Post → Social Media. Uses rssFeedTrigger, httpRequest. Event-driven trigger; 22 nodes.

Rss Feed Trigger, HTTP Request