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Workflow Builder (n8n Engine)

The Workflow Builder is FlowStack's advanced automation engine powered by n8n. It provides a powerful node-based editor for building complex, multi-branch automations with code execution and advanced data transformation.

Interface​

The Workflow Builder opens in a full-featured editor within the FlowStack dashboard:

  • Canvas — Infinite workspace with zoom and pan. Connect nodes by dragging wires between them.
  • Node Panel — Click any node to configure it. Shows input parameters, expressions, and output preview.
  • Node Palette — Search 880+ node types. Organized by category (triggers, actions, utilities, AI).
  • Execution Panel — Shows execution data flowing through each node in real-time.
  • Runs Panel — History of all executions with status and duration.

Building a Workflow​

1. Select a Trigger​

Every workflow starts with a trigger node:

  • Manual Trigger — Run on-demand from the dashboard
  • Schedule Trigger — Cron-based scheduling (every N minutes/hours/days, custom cron)
  • Webhook — HTTP endpoint that accepts GET, POST, PUT, DELETE requests
  • App Trigger — Event from a connected service (e.g., new Slack message, new GitHub PR)

2. Add Nodes​

Click the + button or drag from a node's output to add new nodes:

Action nodes — Interact with external services:

  • Gmail, Slack, Google Sheets, Notion, Airtable, HubSpot, Salesforce, etc.

Utility nodes — Control flow logic:

  • IF — Conditional branching
  • Switch — Multi-way branching based on values
  • Merge — Combine data from multiple branches
  • Loop Over Items — Process arrays one item at a time
  • Wait — Pause execution for a duration or until a webhook is received
  • Set — Create or transform data fields

Code nodes — Execute custom code:

  • Code — Write JavaScript or Python with full require() / import support
  • HTTP Request — Call any REST API with custom headers, auth, and body
  • Execute Command — Run shell commands

AI nodes — Build AI pipelines:

  • AI Agent — Create an agent with tools and memory
  • Chat Model — Connect to OpenAI, Anthropic, Google, etc.
  • Vector Store — Query Pinecone, Weaviate, Qdrant, etc.
  • Text Splitter — Chunk documents for embedding
  • Chain — Build LangChain sequences

3. Configure Expressions​

The Workflow Builder uses a powerful expression system for data mapping:

// Reference data from previous nodes
{{ $json.email }}

// Access nested properties
{{ $json.user.profile.name }}

// Use JavaScript expressions
{{ $json.amount * 1.1 }}

// Access environment variables
{{ $env.API_KEY }}

// Reference specific node output
{{ $node["Gmail"].json.subject }}

4. Error Handling​

Add error handling to make your workflows resilient:

  • Retry on Fail — Automatically retry a node up to N times with configurable delay
  • Continue on Fail — Don't stop the workflow if a node fails
  • Error Trigger — A special trigger that fires when any workflow in the project fails

5. Test and Execute​

  1. Click Execute Workflow to run with test data
  2. Each node shows its output in real-time (green = success, red = failure)
  3. Click any node to inspect input/output data
  4. Pin test data to nodes for consistent testing

Sub-Workflows​

Break complex automations into reusable modules:

  1. Create a workflow that starts with a Manual Trigger or Execute Workflow Trigger
  2. In your main workflow, add an Execute Workflow node
  3. Select the sub-workflow
  4. Pass data in and receive results back

This is ideal for shared logic like "enrich contact data" or "send notification" that's used across multiple workflows.

Webhook Configuration​

Webhook triggers create a unique URL for your workflow:

https://your-n8n-instance.com/webhook/abc123-def456

Configure:

  • HTTP Method — GET, POST, PUT, DELETE, or any
  • Path — Custom path segment
  • Authentication — None, Basic Auth, or Header Auth
  • Response — Immediately or after workflow completes (with custom response body)

Tips​

  • Pin data on nodes to speed up testing without re-executing the full workflow
  • Use sticky notes on the canvas to document complex sections
  • Color-code nodes by right-clicking to visually organize your workflow
  • Use the Code node sparingly — prefer built-in nodes when available for maintainability