n8n-workflow-patterns

What this skill does

# n8n Workflow Patterns

Proven architectural patterns for building n8n workflows.

---

## The 5 Core Patterns

Based on analysis of real workflow usage:

1. **[Webhook Processing](webhook_processing.md)** (Most Common)
   - Receive HTTP requests → Process → Output
   - Pattern: Webhook → Validate → Transform → Respond/Notify

2. **[HTTP API Integration](http_api_integration.md)**
   - Fetch from REST APIs → Transform → Store/Use
   - Pattern: Trigger → HTTP Request → Transform → Action → Error Handler

3. **[Database Operations](database_operations.md)**
   - Read/Write/Sync database data
   - Pattern: Schedule → Query → Transform → Write → Verify

4. **[AI Agent Workflow](ai_agent_workflow.md)**
   - AI agents with tools and memory
   - Pattern: Trigger → AI Agent (Model + Tools + Memory) → Output

5. **[Scheduled Tasks](scheduled_tasks.md)**
   - Recurring automation workflows
   - Pattern: Schedule → Fetch → Process → Deliver → Log

---

## Pattern Selection Guide

### When to use each pattern:

**Webhook Processing** - Use when:
- Receiving data from external systems
- Building integrations (Slack commands, form submissions, GitHub webhooks)
- Need instant response to events
- Example: "Receive Stripe payment webhook → Update database → Send confirmation"

**HTTP API Integration** - Use when:
- Fetching data from external APIs
- Synchronizing with third-party services
- Building data pipelines
- Example: "Fetch GitHub issues → Transform → Create Jira tickets"

**Database Operations** - Use when:
- Syncing between databases
- Running database queries on schedule
- ETL workflows
- Example: "Read Postgres records → Transform → Write to MySQL"

**AI Agent Workflow** - Use when:
- Building conversational AI
- Need AI with tool access
- Multi-step reasoning tasks
- Example: "Chat with AI that can search docs, query database, send emails"

**Scheduled Tasks** - Use when:
- Recurring reports or summaries
- Periodic data fetching
- Maintenance tasks
- Example: "Daily: Fetch analytics → Generate report → Email team"

---

## Common Workflow Components

All patterns share these building blocks:

### 1. Triggers
- **Webhook** - HTTP endpoint (instant)
- **Schedule** - Cron-based timing (periodic)
- **Manual** - Click to execute (testing)
- **Polling** - Check for changes (intervals)

### 2. Data Sources
- **HTTP Request** - REST APIs
- **Database nodes** - Postgres, MySQL, MongoDB
- **Service nodes** - Slack, Google Sheets, etc.
- **Code** - Custom JavaScript/Python

### 3. Transformation
- **Set** - Map/transform fields
- **Code** - Complex logic
- **IF/Switch** - Conditional routing
- **Merge** - Combine data streams

### 4. Outputs
- **HTTP Request** - Call APIs
- **Database** - Write data
- **Communication** - Email, Slack, Discord
- **Storage** - Files, cloud storage

### 5. Error Handling
- **Error Trigger** - Catch workflow errors
- **IF** - Check for error conditions
- **Stop and Error** - Explicit failure
- **Continue On Fail** - Per-node setting

---

## Workflow Creation Checklist

When building ANY workflow, follow this checklist:

### Planning Phase
- [ ] Identify the pattern (webhook, API, database, AI, scheduled)
- [ ] List required nodes (use search_nodes)
- [ ] Understand data flow (input → transform → output)
- [ ] Plan error handling strategy

### Implementation Phase
- [ ] Create workflow with appropriate trigger
- [ ] Add data source nodes
- [ ] Configure authentication/credentials
- [ ] Add transformation nodes (Set, Code, IF)
- [ ] Add output/action nodes
- [ ] Configure error handling

### Validation Phase
- [ ] Validate each node configuration (validate_node)
- [ ] Validate complete workflow (validate_workflow)
- [ ] Test with sample data
- [ ] Handle edge cases (empty data, errors)

### Deployment Phase
- [ ] Review workflow settings (execution order, timeout, error handling)
- [ ] Activate workflow using `activateWorkflow` operation
- [ ] Monitor first executions
- [ ] Document workflow purpose and data flow

---

## Data Flow Patterns

### Linear Flow
```
Trigger → Transform → Action → End
```
**Use when**: Simple workflows with single path

### Branching Flow
```
Trigger → IF → [True Path]
             └→ [False Path]
```
**Use when**: Different actions based on conditions

### Parallel Processing
```
Trigger → [Branch 1] → Merge
       └→ [Branch 2] ↗
```
**Use when**: Independent operations that can run simultaneously

### Loop Pattern
```
Trigger → Split in Batches → Process → Loop (until done)
```
**Use when**: Processing large datasets in chunks

### Error Handler Pattern
```
Main Flow → [Success Path]
         └→ [Error Trigger → Error Handler]
```
**Use when**: Need separate error handling workflow

---

## Common Gotchas

### 1. Webhook Data Structure
**Problem**: Can't access webhook payload data

**Solution**: Data is nested under `$json.body`
```javascript
❌ {{$json.email}}
✅ {{$json.body.email}}
```
See: n8n Expression Syntax skill

### 2. Multiple Input Items
**Problem**: Node processes all input items, but I only want one

**Solution**: Use "Execute Once" mode or process first item only
```javascript
{{$json[0].field}}  // First item only
```

### 3. Authentication Issues
**Problem**: API calls failing with 401/403

**Solution**:
- Configure credentials properly
- Use the "Credentials" section, not parameters
- Test credentials before workflow activation

### 4. Node Execution Order
**Problem**: Nodes executing in unexpected order

**Solution**: Check workflow settings → Execution Order
- v0: Top-to-bottom (legacy)
- v1: Connection-based (recommended)

### 5. Expression Errors
**Problem**: Expressions showing as literal text

**Solution**: Use {{}} around expressions
- See n8n Expression Syntax skill for details

---

## Integration with Other Skills

These skills work together with Workflow Patterns:

**n8n MCP Tools Expert** - Use to:
- Find nodes for your pattern (search_nodes)
- Understand node operations (get_node)
- Create workflows (n8n_create_workflow)
- Deploy templates (n8n_deploy_template)
- Use ai_agents_guide for AI pattern guidance

**n8n Expression Syntax** - Use to:
- Write expressions in transformation nodes
- Access webhook data correctly ({{$json.body.field}})
- Reference previous nodes ({{$node["Node Name"].json.field}})

**n8n Node Configuration** - Use to:
- Configure specific operations for pattern nodes
- Understand node-specific requirements

**n8n Validation Expert** - Use to:
- Validate workflow structure
- Fix validation errors
- Ensure workflow correctness before deployment

---

## Pattern Statistics

Common workflow patterns:

**Most Common Triggers**:
1. Webhook - 35%
2. Schedule (periodic tasks) - 28%
3. Manual (testing/admin) - 22%
4. Service triggers (Slack, email, etc.) - 15%

**Most Common Transformations**:
1. Set (field mapping) - 68%
2. Code (custom logic) - 42%
3. IF (conditional routing) - 38%
4. Switch (multi-condition) - 18%

**Most Common Outputs**:
1. HTTP Request (APIs) - 45%
2. Slack - 32%
3. Database writes - 28%
4. Email - 24%

**Average Workflow Complexity**:
- Simple (3-5 nodes): 42%
- Medium (6-10 nodes): 38%
- Complex (11+ nodes): 20%

---

## Quick Start Examples

### Example 1: Simple Webhook → Slack
```
1. Webhook (path: "form-submit", POST)
2. Set (map form fields)
3. Slack (post message to #notifications)
```

### Example 2: Scheduled Report
```
1. Schedule (daily at 9 AM)
2. HTTP Request (fetch analytics)
3. Code (aggregate data)
4. Email (send formatted report)
5. Error Trigger → Slack (notify on failure)
```

### Example 3: Database Sync
```
1. Schedule (every 15 minutes)
2. Postgres (query new records)
3. IF (check if records exist)
4. MySQL (insert records)
5. Postgres (update sync timestamp)
```

### Example 4: AI Assistant
```
1. Webhook (receive chat message)
2. AI Agent
   ├─ OpenAI Chat Model (ai_languageModel)
   ├─ HTTP Request Tool (ai_tool)
   ├─ Database Tool (ai_tool)
   └─ Window Buffer Memory (ai_memory)
3. Webhook Response (send AI re