Imported from David-Li0406/meta-skill-evloving (skill-flow/data/skills-refined-skillclaw-36k/skillsmp/n8n-2/SKILL.md). Install upstream with npx skills add David-Li0406/meta-skill-evloving --skill n8n-2. Copyright stays with the author.

n8n Workflow Automation Skill

Purpose

Provide specialized guidance for developing workflows, custom nodes, and integrations on the n8n automation platform. Enable AI assistants to design workflows, write custom code nodes, build TypeScript-based custom nodes, integrate external services, and implement AI agent patterns.

When to Use This Skill

Invoke this skill when:

• Designing automation workflows combining multiple services
• Writing JavaScript/Python code within workflow nodes
• Building custom nodes in TypeScript
• Integrating APIs, databases, and cloud services
• Creating AI agent workflows with LangChain
• Troubleshooting workflow execution errors
• Planning self-hosted n8n deployments
• Converting manual processes to automated workflows

Do NOT use this skill for:

• Generic automation advice (use appropriate language/platform skill)
• Cloud platform-specific integrations (combine with cloud provider skill)
• Database design (use database-specialist skill)
• Frontend development (n8n has minimal UI customization)

Core n8n Concepts

Platform Architecture

Runtime Environment:

• Node.js-based execution engine
• TypeScript (90.7%) and Vue.js frontend
• pnpm monorepo structure
• Self-hosted or cloud deployment options

Workflow Execution Models:

1. Manual trigger - User-initiated execution
2. Webhook trigger - HTTP endpoint activation
3. Schedule trigger - Cron-based timing
4. Event trigger - External service events (database changes, file uploads)
5. Error trigger - Workflow failure handling

Fair-code License:

• Apache 2.0 with Commons Clause
• Free for self-hosting and unlimited executions
• Commercial restrictions for SaaS offerings

Node Types and Categories

Core Nodes (Data manipulation):

• Code - Execute JavaScript/Python
• Set - Assign variable values
• If - Conditional branching
• Switch - Multi-branch routing
• Merge - Combine data streams
• Split In Batches - Process large datasets incrementally
• Loop Over Items - Iterate through data

Trigger Nodes (Workflow initiation):

• Webhook - HTTP endpoint
• Schedule - Time-based execution
• Manual Trigger - User activation
• Error Trigger - Catch workflow failures
• Start - Default entry point

Action Nodes (500+ integrations):

• API connectors (REST, GraphQL, SOAP)
• Database clients (PostgreSQL, MongoDB, MySQL, Redis)
• Cloud services (AWS, GCP, Azure, Cloudflare)
• Communication (Email, Slack, Discord, SMS)
• File operations (FTP, S3, Google Drive, Dropbox)
• Authentication (OAuth2, API keys, JWT)

AI Nodes (LangChain integration):

• AI Agent - Autonomous decision-making
• AI Chain - Sequential LLM operations
• AI Transform - Data manipulation with LLMs
• Vector Store - Embedding storage and retrieval
• Document Loaders - Text extraction from files

Data Flow and Connections

Connection Types:

1. Main connection - Primary data flow (solid line)
2. Error connection - Failure routing (dashed red line)

Data Structure:

// Input/output format for all nodes
[
  {
    json: { /* Your data object */ },
    binary: { /* Optional binary data (files, images) */ },
    pairedItem: { /* Reference to source item */ }
  }
]

Data Access Patterns:

• Expression - {{ $json.field }} (current node output)
• Input reference - {{ $('NodeName').item.json.field }} (specific node)
• All items - {{ $input.all() }} (entire dataset)
• First item - {{ $input.first() }} (single item)
• Item index - {{ $itemIndex }} (current iteration)

Credentials and Authentication

Credential Types:

• Predefined - Pre-configured for popular services (OAuth2, API key)
• Generic - HTTP authentication (Basic, Digest, Header Auth)
• Custom - User-defined credential structures

Security Practices:

• Credentials stored encrypted in database
• Environment variable support for sensitive values
• Credential sharing across workflows (optional)
• Rotation: Manual update required

Workflow Design Methodology

Planning Phase

Step 1: Define Requirements

• Input sources (webhooks, schedules, databases)
• Data transformations needed
• Output destinations (APIs, files, databases)
• Error handling requirements
• Execution frequency and volume

Step 2: Map Data Flow

• Identify trigger events
• List transformation steps
• Specify validation rules
• Define branching logic
• Plan error recovery

Step 3: Select Nodes

Decision criteria:

• Use native nodes when available (optimized, maintained)
• Use Code node for custom logic <50 lines
• Build custom node for reusable complex logic >100 lines
• Use HTTP Request node for APIs without native nodes
• Use Execute Command node for system operations (security risk)

Implementation Phase

Workflow Structure Pattern:

[Trigger] → [Validation] → [Branch (If/Switch)] → [Processing] → [Error Handler]
                                ↓                      ↓
                          [Path A nodes]        [Path B nodes]
                                ↓                      ↓
                          [Merge/Output]         [Output]

Modular Design:

• Extract reusable logic to sub-workflows
• Use Execute Workflow node for modularity
• Limit main workflow to 15-20 nodes (readability)
• Parameterize workflows with input variables

Error Handling Strategy:

1. Error Trigger workflows - Capture all failures
2. Try/Catch pattern - Error output connections on nodes
3. Retry logic - Configure per-node retry settings
4. Validation nodes - If/Switch for data checks
5. Notification - Alert on critical failures (Email, Slack)

Testing Phase

Local Testing:

• Execute with sample data
• Verify each node output (inspect data panel)
• Test error paths with invalid data
• Check credential connections

Production Validation:

• Enable workflow, monitor executions
• Review execution history for failures
• Check resource usage (execution time, memory)
• Validate output data quality

Code Execution in Workflows

Code Node (JavaScript)

Available APIs:

• Node.js built-ins - fs, path, crypto, https
• Lodash - _.groupBy(), _.sortBy(), etc.
• Luxon - DateTime manipulation
• n8n helpers - $input, $json, $binary

Basic Structure:

// Access input items
const items = $input.all();

// Process data
const processedItems = items.map(item => {
  const inputData = item.json;

  return {
    json: {
      // Output fields
      processed: inputData.field.toUpperCase(),
      timestamp: new Date().toISOString()
    }
  };
});

// Return transformed items
return processedItems;

Data Transformation Patterns:

Filtering:

const items = $input.all();
return items.filter(item => item.json.status === 'active');

Aggregation:

const items = $input.all();
const grouped = _.groupBy(items, item => item.json.category);

return [{
  json: {
    summary: Object.keys(grouped).map(category => ({
      category,
      count: grouped[category].length
    }))
  }
}];

API calls (async):

const items = $input.all();
const results = [];

for (const item of items) {
  const response = await fetch(`https://api.example.com/data/${item.json.id}`);
  const data = await response.json();

  results.push({
    json: {
      original: item.json,
      enriched: data
    }
  });
}

return results;

Error Handling in Code:

const items = $input.all();

return items.map(item => {
  try {
    // Risky operation
    const result = JSON.parse(item.json.data);
    return { json: { parsed: result } };
  } catch (error) {
    return {
      json: {
        error: error.message,
        original: item.json.data
      }
    };
  }
});

Code Node (Python)

Available Libraries:

• Standard library - json, datetime, re, requests
• NumPy - Array operations
• Pandas - Data analysis (if installed)

Basic Structure:

# Access input items
items = _input.all()

# Process data
processed_items = []
for item in items:
    input_data = item['json']

    processed_items.append({
        'json': {
            'processed': input_data['field'].upper(),
            'timestamp': datetime.now().isoformat()
        }
    })

# Return transformed items
return processed_items

Complexity Rating: Code Nodes

• Simple transformations (map/filter): 1
• API calls with error handling: 2
• Multi-step async operations: 3
• Complex algorithms with libraries: 4
• Performance-critical processing: 5 (consider custom node)

Custom Node Development

When to Build Custom Nodes

Build custom node when:

• Reusable logic across multiple workflows (>3 workflows)
• Complex authentication requirements
• Performance-critical operations (Code node overhead)
• Community contribution (public npm package)
• Organization-specific integrations

Use Code node when:

• One-off transformations
• Rapid prototyping
• Simple API calls (<100 lines)

Development Styles

[See Code Examples: examples/n8n_custom_node.ts]

1. Programmatic Style (Full control)

Use for:

• Complex authentication flows
• Advanced parameter validation
• Custom UI components
• Polling operations with state management

[See: CustomNode class in examples/n8n_custom_node.ts]

2. Declarative Style (Simplified)

Use for:

• Standard CRUD operations
• RESTful API wrappers
• Simple integrations without complex logic

[See: operations and router exports in examples/n8n_custom_node.ts]

Additional Examples:

• Credential configuration: customApiCredentials in examples/n8n_custom_node.ts
• Credential validation: validateCredentials() in examples/n8n_custom_node.ts
• Polling trigger: PollingTrigger class in examples/n8n_custom_node.ts

Development Workflow

Step 1: Initialize Node

# Create from template
npm create @n8n/node my-custom-node

# Directory structure created:
# ├── nodes/
# │   └── MyCustomNode/
# │       └── MyCustomNode.node.ts
# ├── credentials/
# │   └── MyCustomNodeApi.credentials.ts
# └── package.json

Step 2: Implement Logic

• Define node properties (parameters, credentials)
• Implement execute method
• Add error handling
• Write unit tests (optional)

Step 3: Build and Test

# Build TypeScript
npm run build

# Link locally for testing
npm link

# In n8n development environment
cd ~/.n8n/nodes
npm link my-custom-node

# Restart n8n to load node
n8n start

Step 4: Publish

# Community node (npm package)
npm publish

# Install in n8n
Settings → Community Nodes → Install → Enter package name

Complexity Rating: Custom Nodes

• Declarative CRUD wrapper: 2
• Programmatic with authentication: 3
• Complex state management: 4
• Advanced polling/webhooks: 5

Integration Patterns

API Integration Strategy

Decision Tree:

Has native node? ──Yes──> Use native node
     │
     No
     ├──> Simple REST API? ──Yes──> HTTP Request node
     ├──> Complex auth (OAuth2)? ──Yes──> Build custom node
     ├──> Reusable across workflows? ──Yes──> Build custom node
     └──> One-off integration? ──Yes──> Code node with fetch()

HTTP Request Node Patterns

GET with query parameters:

URL: https://api.example.com/users
Method: GET
Query Parameters:
  - status: active
  - limit: 100
Authentication: Header Auth
  - Name: Authorization
  - Value: Bearer {{$credentials.apiKey}}

POST with JSON body:

URL: https://api.example.com/users
Method: POST
Body Content Type: JSON
Body:
{
  "name": "={{ $json.name }}",
  "email": "={{ $json.email }}"
}

Pagination handling (Code node):

let allResults = [];
let page = 1;
let hasMore = true;

while (hasMore) {
  const response = await this.helpers.request({
    method: 'GET',
    url: `https://api.example.com/data?page=${page}`,
    json: true,
  });

  allResults = allResults.concat(response.results);
  hasMore = response.hasNext;
  page++;
}

return allResults.map(item => ({ json: item }));

Webhook Patterns

Receiving webhooks:

1. Create webhook trigger node
2. Configure HTTP method (POST/GET)
3. Set authentication (None/Header Auth/Basic Auth)
4. Get webhook URL from node
5. Register URL with external service

Responding to webhooks:

// In Code node after webhook trigger
const webhookData = $input.first().json;

// Process data
const result = processData(webhookData);

// Return response (synchronous webhook)
return [{
  json: {
    status: 'success',
    data: result
  }
}];

Webhook URL structure:

Production: https://your-domain.com/webhook/workflow-id
Test: https://your-domain.com/webhook-test/workflow-id

Database Integration

Common patterns:

Query with parameters:

-- PostgreSQL node
SELECT * FROM users
WHERE created_at > $1
  AND status = $2
ORDER BY created_at DESC

-- Parameters from previous node
Parameters: ['{{ $json.startDate }}', 'active']

Batch insert:

// Code node preparing data for database
const items = $input.all();
const values = items.map(item => ({
  name: item.json.name,
  email: item.json.email,
  created_at: new Date().toISOString()
}));

return [{ json: { values } }];

// Next node: PostgreSQL
// INSERT INTO users (name, email, created_at)
// VALUES {{ $json.values }}

File Operations

Upload to S3:

Workflow: File Trigger → S3 Upload
- File Trigger: Monitor directory for new files
- S3 node:
  - Operation: Upload
  - Bucket: my-bucket
  - File Name: {{ $json.fileName }}
  - Binary Data: true (from file trigger)

Download and process:

HTTP Request (download) → Code (process) → Google Drive (upload)
- HTTP Request: Binary response enabled
- Code: Process $binary.data
- Google Drive: Upload with binary data

AI Agent Workflows

LangChain Integration

AI Agent Node Configuration:

• Agent type: OpenAI Functions, ReAct, Conversational
• LLM: OpenAI, Anthropic, Hugging Face, Ollama (local)
• Memory: Buffer, Buffer Window, Summary
• Tools: Calculator, Webhook, Database query, Custom API calls

Basic Agent Pattern:

Manual Trigger → AI Agent → Output
- AI Agent:
  - Prompt: "You are a helpful assistant that {{$json.task}}"
  - Tools: [Calculator, HTTP Request]
  - Memory: Conversation Buffer Window

Gatekeeper Pattern (Supervised AI)

Use case: Human approval before agent actions

Webhook → AI Agent → If (requires approval) → Send Email → Wait for Webhook → Execute Action
                            ↓ (auto-approve)
                        Execute Action

Implementation:

1. AI Agent generates action plan
2. If node checks confidence score
3. Low confidence → Email approval request
4. Wait for webhook (approve/reject)
5. Execute or abort based on response

Iterative Agent Pattern

Use case: Multi-step problem solving with state

Loop Start → AI Agent → Tool Execution → State Update → Loop End (condition check)
     ↑______________________________________________________________|

State management:

// Code node - Initialize state
return [{
  json: {
    task: 'Research topic',
    iteration: 0,
    maxIterations: 5,
    context: [],
    completed: false
  }
}];

// Code node - Update state
const state = $json;
state.iteration++;
state.context.push($('AI Agent').item.json.response);
state.completed = state.iteration >= state.maxIterations || checkGoalMet(state);

return [{ json: state }];

RAG (Retrieval Augmented Generation) Pattern

Query Input → Vector Store Search → Format Context → LLM → Response Output

Vector Store setup:

1. Document Loader node → Split text into chunks
2. Embeddings node → Generate vectors (OpenAI, Cohere)
3. Vector Store node → Store in Pinecone/Qdrant/Supabase
4. Query: Retrieve relevant chunks → Inject into LLM prompt

Complexity Rating: AI Workflows

• Simple LLM call: 1
• Agent with tools: 3
• Gatekeeper pattern: 4
• Multi-agent orchestration: 5

Deployment and Hosting

Self-Hosting Options

[See Code Examples: examples/n8n_deployment.yaml]

Docker (Recommended):

• Docker Compose with PostgreSQL
• Queue mode configuration for scaling
• Resource requirements by volume

[See: docker-compose configurations in examples/n8n_deployment.yaml]

npm (Development):

npm install n8n -g
n8n start
# Access: http://localhost:5678

Environment Configuration:

[See: Complete environment variable reference in examples/n8n_deployment.yaml]

Essential variables:

• N8N_HOST - Public URL for webhooks
• WEBHOOK_URL - Webhook endpoint base
• N8N_ENCRYPTION_KEY - Credential encryption (must persist)
• DB_TYPE - Database (SQLite/PostgreSQL/MySQL/MariaDB)
• EXECUTIONS_DATA_SAVE_ON_ERROR - Error logging
• EXECUTIONS_DATA_SAVE_ON_SUCCESS - Success logging

Performance tuning variables documented in examples/n8n_deployment.yaml

Scaling Considerations

Queue Mode (High volume):

# Separate main and worker processes
# Main process (UI + queue management)
N8N_QUEUE_MODE=main n8n start

# Worker processes (execution only)
N8N_QUEUE_MODE=worker n8n worker

Database:

• SQLite: Development/low volume (<1000 executions/day)
• PostgreSQL: Production (recommended)
• MySQL/MariaDB: Alternative for existing infrastructure

Resource Requirements:

Monitoring:

• Enable execution logs (EXECUTIONS_DATA_SAVE_*)
• Set up error workflows (Error Trigger node)
• Monitor database size (execution history cleanup)
• Track webhook response times

Best Practices

Workflow Design

1. Modularity:

• Extract reusable logic to Execute Workflow nodes
• Limit workflows to single responsibility
• Use sub-workflows for common operations (validation, formatting)

2. Error Resilience:

• Add error outputs to critical nodes
• Implement retry logic (node settings)
• Create Error Trigger workflows for alerts
• Log errors to external systems (Sentry, CloudWatch)

3. Performance:

• Use Split In Batches for large datasets (>1000 items)
• Minimize HTTP requests in loops (batch API calls)
• Disable execution logging for high-frequency workflows
• Cache expensive operations in variables

4. Security:

• Store secrets in credentials (not hardcoded)
• Use environment variables for configuration
• Enable webhook authentication
• Restrict Execute Command node usage (or disable globally)
• Review code nodes for injection vulnerabilities

5. Maintainability:

• Add notes to complex workflows (Sticky Note node)
• Use consistent naming (verb + noun: "Fetch Users", "Transform Data")
• Document workflow purpose in workflow settings
• Version control workflows (export JSON, commit to Git)

Code Quality in Nodes

1. Data validation:

// Always validate input structure
const items = $input.all();

for (const item of items) {
  if (!item.json.email || !item.json.name) {
    throw new Error(`Invalid input: missing required fields at item ${item.json.id}`);
  }
}

2. Error context:

// Provide debugging information
try {
  const result = await apiCall(item.json.id);
} catch (error) {
  throw new Error(`API call failed for ID ${item.json.id}: ${error.message}`);
}

3. Idempotency:

// Check existence before creation
const exists = await checkExists(item.json.uniqueId);
if (!exists) {
  await createRecord(item.json);
}

Workflow Pattern Library

Pattern 1: API Sync

Use case: Sync data between two systems

Schedule Trigger (hourly) → Fetch Source Data → Transform → If (record exists) → Update Target
                                                                    ↓ (new)
                                                                Create in Target

Complexity: 2

Pattern 2: Error Recovery

Use case: Retry failed operations with exponential backoff

Main Workflow → Process → Error → Error Trigger Workflow
                                        ↓
                                   Wait (delay) → Retry → If (max retries) → Alert

Complexity: 3

Pattern 3: Data Enrichment

Use case: Augment data with external sources

Webhook → Split In Batches → For Each Item:
                                  ↓
                             API Call (enrich) → Code (merge) → Batch Results
                                                                      ↓
                                                                Database Insert

Complexity: 3

Pattern 4: Event-Driven Processing

Use case: Process events from message queue

SQS Trigger → Parse Message → Switch (event type) → [Handler A, Handler B, Handler C] → Confirm/Delete Message

Complexity: 3

Pattern 5: Human-in-the-Loop

Use case: Approval workflow

Trigger → Generate Request → Send Email (approval link) → Webhook (approval response) → If (approved) → Execute Action
                                                                                              ↓ (rejected)
                                                                                         Send Rejection Notice

Complexity: 4

Pattern 6: Multi-Stage ETL

Use case: Complex data pipeline

Schedule → Extract (API) → Validate → Transform → Load (Database) → Success Notification
                               ↓                                            ↓
                          Error Handler ────────────────────> Error Notification

Complexity: 3

Quality Gates

Definition of Done: Workflows

A workflow is production-ready when:

1. Functionality:

   • ✓ All nodes execute without errors on test data
   • ✓ Error paths tested with invalid input
   • ✓ Output format validated against requirements

2. Error Handling:

   • ✓ Error outputs configured on critical nodes
   • ✓ Error Trigger workflow created for alerts
   • ✓ Retry logic configured where applicable

3. Security:

   • ✓ Credentials used (no hardcoded secrets)
   • ✓ Webhook authentication enabled
   • ✓ Input validation implemented

4. Documentation:

   • ✓ Workflow description filled in settings
   • ✓ Complex logic documented with notes
   • ✓ Parameter descriptions clear

5. Performance:

   • ✓ Tested with realistic data volume
   • ✓ Execution time acceptable
   • ✓ Resource usage within limits

Definition of Done: Custom Nodes

A custom node is production-ready when:

1. Functionality:

   • ✓ All operations implemented and tested
   • ✓ Credentials integration working
   • ✓ Parameters validated

2. Code Quality:

   • ✓ TypeScript types defined
   • ✓ Error handling comprehensive
   • ✓ No hardcoded values (use parameters)

3. Documentation:

   • ✓ README with installation instructions
   • ✓ Parameter descriptions clear
   • ✓ Example workflows provided

4. Distribution:

   • ✓ Published to npm (if public)
   • ✓ Versioned appropriately
   • ✓ Dependencies declared in package.json

Error Handling Guide

Common Issues and Resolutions

Issue: Workflow fails with "Invalid JSON"

• Cause: Node output not in correct format
• Resolution:

  // Ensure return format
  return [{ json: { your: 'data' } }];
  // NOT: return { your: 'data' };

Issue: "Cannot read property of undefined"

• Cause: Missing data from previous node
• Resolution:

  // Check existence before access
  const value = $json.field?.subfield ?? 'default';

Issue: Webhook not receiving data

• Cause: Incorrect webhook URL or authentication
• Resolution:
  • Verify URL matches external service configuration
  • Check authentication method matches (None/Header/Basic)
  • Test with curl:

    curl -X POST https://your-n8n.com/webhook/test \
      -H "Content-Type: application/json" \
      -d '{"test": "data"}'

Issue: Custom node not appearing

• Cause: Not properly linked/installed
• Resolution:

  # Check installation
  npm list -g | grep n8n-nodes-
  
  # Reinstall if needed
  npm install -g n8n-nodes-your-node
  
  # Restart n8n

Issue: High memory usage

• Cause: Processing large datasets without batching
• Resolution:
  • Use Split In Batches node (batch size: 100-1000)
  • Disable execution data saving for high-frequency workflows
  • Set EXECUTIONS_DATA_PRUNE=true

Issue: Credentials not working

• Cause: Incorrect credential configuration or expired tokens
• Resolution:
  • Re-authenticate OAuth2 credentials
  • Verify API key/token validity
  • Check credential permissions in service

Debugging Strategies

1. Inspect node output:

• Click node → View executions data
• Check json and binary tabs
• Verify data structure matches expectations

2. Add debug Code nodes:

// Log intermediate values
const data = $json;
console.log('Debug data:', JSON.stringify(data, null, 2));
return [{ json: data }];

3. Use If node for validation:

// Expression to check data quality
{{ $json.email && $json.email.includes('@') }}

4. Enable execution logging:

• Settings → Log → Set level to debug
• Check docker logs: docker logs n8n -f

5. Test in isolation:

• Create test workflow with Manual Trigger
• Copy problematic nodes
• Use static test data

References

Official Documentation

• Main docs: https://docs.n8n.io
• Node reference: https://docs.n8n.io/integrations/builtin/
• Custom node development: https://docs.n8n.io/integrations/creating-nodes/
• Expression reference: https://docs.n8n.io/code/expressions/

Code Repositories

• Core platform: https://github.com/n8n-io/n8n
• Documentation: https://github.com/n8n-io/n8n-docs
• Community nodes: https://www.npmjs.com/search?q=n8n-nodes

Community Resources

• Forum: https://community.n8n.io
• Templates: https://n8n.io/workflows (workflow library)
• YouTube: Official n8n channel (tutorials)

Related Skills

• For cloud integrations: Use cloud-devops-expert skill
• For database design: Use database-specialist skill
• For API design: Use api-design-architect skill
• For TypeScript development: Use language-specific skills

Version: 1.0.0 Last Updated: 2025-11-13 Complexity Rating: 3 (Moderate - requires platform-specific knowledge) Estimated Learning Time: 8-12 hours for proficiency