## Describe the problem/error/question
I need to trigger a dynamic number of sub-workflows in parallel (around 100)
and wait for ALL of them to complete before continuing the main workflow.
I’ve implemented a solution but I’m wondering if there’s a better or more elegant approach.
**My Current Implementation:**
**Main Workflow:**
1. Triggers N sub-workflows via HTTP Request node with `Execute Once: false`
2. Passes the total count of sub-workflows (e.g., 100) to each sub-workflow
3. Uses a Wait node (Wait for Webhook Resume) to pause execution
**Each Sub-Workflow:**
1. Performs its work (calls external LLM via MCP, takes 2-5 minutes)
2. When complete, sends an HTTP callback to a “Collector Workflow”
**Collector Workflow:**
1. Receives callbacks from completed sub-workflows
2. Maintains a counter of completed tasks
3. When counter reaches N/N (all sub-workflows finished), it resumes the main workflow via webhook
**My Questions:**
- Is this a good pattern for handling 100+ parallel sub-workflows?
- Is there a built-in n8n feature or node that can handle this more elegantly?
- Should I be using the Merge node differently, or is the callback + counter approach appropriate?
- Are there any performance considerations or limitations I should be aware of?
**Key Requirements:**
- Dynamic number of sub-workflows (not fixed)
- Each sub-workflow is long-running (2-5 minutes) use callback solution
- Main workflow must wait for ALL sub-workflows to complete
- Need to collect and process all results together
I’m open to completely different approaches if there’s a better way to architect this!
**Main Workflow Structure:**
**Sub-Workflow Structure:**
when callback return from the long process → call to the Collector workflow
**Collector Workflow Structure:**
The final output is a collection of all sub-workflow results that need to be merged and processed together in the main workflow.
