n8n Workflow Support

Production-ready patterns for n8n workflow automation that work around platform limitations.

Quick Start Checklist

Before generating ANY n8n workflow:

1. Nested loops? → Use sub-workflows (ONLY reliable method)
2. Need state? → Use Data Tables (50MB limit per table)
3. Parallel processing? → Must have Merge node to converge
4. Status updates? → Keep HTTP callbacks inline, never parallel
5. Google Sheets? → Use Append in loops, not Update
6. Complex data flow? → Create multiple specialized Data Tables

Critical Platform Knowledge

✅ What Actually Works

• Sub-workflows: Clean execution contexts for nested operations
• Native Data Tables: Primary state management solution
• Conditional Loop-Back: Using IF nodes to branch back
• Webhook Callbacks: For async coordination (inline only)
• Pass-Through State: State in item JSON data
• Merge Nodes: Left joins instead of nested loops
• Google Sheets Append: For data capture in loops

❌ Broken Features (DO NOT USE)

• Direct nested Loop Over Items → State corruption guaranteed
• $workflow.staticData in Code nodes → Does not exist
• Microsoft Excel in loops → Fails silently
• Loop state auto-reset → Doesn't happen
• Parallel callbacks → May never execute
• Memory-based state → Not persistent

Core Workflow Patterns

Pattern 1: Simple Loop with State

[Initialize Data] → [Data Table: Init] → [Process] → [IF: Continue?]
                            ↑                              ↓ false
                            └──────────── true ────────────┘
                                                           ↓
                                                      [Continue]

Pattern 2: Nested Operations (Sub-workflows Required)

Main: [Loop Over Items] → [Execute Sub-workflow] → [Merge/Wait] → [Continue]
                                    ↓
                            [Clean Context]
                                    ↓
Sub: [Inner Loop] → [Process] → [Webhook Callback]

Pattern 3: Parallel Processing with Convergence

[Split In Batches] → [Execute Workflow] → [Merge (Wait All)] → [Aggregate]
         ↓                                         ↑
    [Parallel Branches] ───────────────────────────┘

Pattern 4: Data Enrichment Without Nesting

[Load Reference] → [Store in Table] → [Process Items] → [Merge by Key]
                                              ↓
                                    [Enrich Input 1 Mode]

Data Table Architecture

Essential Tables Structure

Create multiple tables for complex workflows:

// execution_tracker - Core execution state
{
  execution_id: "string (PK)",
  entity_type: "string",
  entity_id: "string", 
  status: "processing|complete|error",
  parent_id: "string",
  metadata: "json",
  created_at: "datetime"
}

// content_storage - Generated content
{
  content_id: "string (PK)",
  entity_id: "string",
  content_type: "string",
  content: "json",
  version: "number",
  created_at: "datetime"
}

// workflow_state - Temporary state
{
  state_id: "string (PK)",
  execution_id: "string",
  state_key: "string",
  state_value: "json",
  expires_at: "datetime"
}

Code Node Patterns

Initialize Loop State

// Always pass state through items
return [{
  json: {
    _execution_id: $execution.id,
    _iteration: 0,
    _max_iterations: 10,
    data: $json,
    _continue: true
  }
}];

Increment Counter

// State in item, not static variables
return [{
  json: {
    ...$json,
    _iteration: ($json._iteration || 0) + 1,
    _continue: ($json._iteration + 1) < $json._max_iterations
  }
}];

Check Dependencies

// For complex workflows with dependencies
const canProceed = $json.required_items?.every(
  item => $json.completed_items?.includes(item)
);
return [{
  json: {
    ...$json,
    can_proceed: canProceed,
    status: canProceed ? "ready" : "waiting"
  }
}];

Error Handling

Every workflow needs:

1. Error Trigger workflow (separate)
2. Exponential backoff: Wait = 2^retry_count seconds
3. Max retries: 3
4. Error logging in Data Table
5. Dead letter pattern for failures

Node Configurations

Loop Over Items

{
  "batchSize": 1,
  "options": {
    "pauseBetweenItems": 100
  }
}

Execute Sub-workflow

{
  "source": "database",
  "workflow": "{{ $json.workflow_id }}",
  "waitForSubWorkflow": false,
  "options": {
    "shareParentExecutionId": false
  }
}

Merge Node (for parallel convergence)

{
  "mode": "waitForAll",
  "outputKey": "combined",
  "keepOnlyProperties": false
}

Data Table Upsert

{
  "operation": "upsert",
  "tableId": "{{ $json.table_name }}",
  "fieldsToMatch": ["execution_id", "entity_id"],
  "options": {
    "returnData": true
  }
}

Testing Checklist

Before deployment:

• All nested loops use sub-workflows
• Data Tables initialized properly
• No staticData in Code nodes
• Google Sheets uses Append in loops
• All parallel branches converge
• HTTP callbacks are inline
• Max iteration safeguards in place
• Error handling implemented
• Tested with 0, 1, and many items

Advanced Patterns

For complex patterns, see references:

• Multi-tier workflows: See references/hierarchical-workflows.md
• Table management: See references/table-manager.md
• Anti-patterns: See references/anti-patterns.md
• GitHub issues: See references/known-issues.md

Webhook Patterns

Status Update (Inline)

[Process] → [HTTP: Update Status] → [Check Response] → [Continue]
                    ↓
            [Must wait for response]

Async Callback

Main: [Execute Sub] → [Wait Node (Resume on Webhook)] → [Process Result]
                                    ↑
Sub: [Process] → [HTTP: Callback] ─┘

Quick Fixes

Loop Only Runs Once?

• Solution: Use sub-workflow for inner loop
• Why: Execution context pollution

Parallel Tasks Not Completing?

• Solution: Add Merge node with waitForAll
• Why: n8n needs explicit convergence

Callbacks Not Firing?

• Solution: Move HTTP callback inline
• Why: Parallel branches may not execute

State Not Persisting?

• Solution: Use Data Tables, not variables
• Why: No static data in Code nodes

When to Call Scripts

• Table setup: Run scripts/table-manager.py first
• Workflow generation: Use scripts/generate-workflow.py
• Validation: Run scripts/validate-workflow.py