logo_smallAxellero.io

Flow Control

Nodes for controlling workflow execution flow and defining entry/exit points.

Flow control nodes manage the execution path of your workflows, enabling conditional logic, loops, error handling, workflow boundaries, and nested execution.

Workflow Boundary Nodes

NodeDescriptionUse Case
StartWorkflow entry point with input validationDefine workflow data contracts
EndWorkflow exit point with response formattingConfigure API responses and outputs

Execution Control Nodes

NodeDescriptionUse Case
BranchConditional branching based on expressionsRoute execution based on data
LoopIterate over arrays or execute repeated logicProcess collections and repetitive tasks
Error HandlerCatch and handle errors gracefullyImplement error recovery patterns
Nested WorkflowExecute another workflow as a sub-processReuse logic and create modular workflows

Workflow Design Patterns

Entry Point Pattern (Start Node)

The Start node establishes the workflow's data contract:

  • Input validation: Define required fields and data types
  • Test configuration: Set up test values for development
  • Trigger integration: Works with HTTP, Schedule, GraphQL, and SOAP triggers
  • Security: Configure authentication and input sanitization

Common patterns:

  • REST and GraphQL API endpoints
  • SOAP web services for legacy integration
  • Scheduled data processing pipelines
  • Automated workflow triggers

Exit Point Pattern (End Node)

The End node defines how workflows respond to callers:

  • Response formatting: Structure API responses consistently
  • HTTP configuration: Set status codes, headers, and content types
  • Error handling: Map workflow errors to appropriate HTTP responses
  • Integration: Support REST APIs, webhooks, and file downloads

Common patterns:

  • RESTful API endpoints with proper status codes
  • Webhook responses for external system notifications
  • Data transformation outputs with metadata

Use Cases

  • API Development: Use Start/End nodes for RESTful API endpoints
  • Data Integration: Process incoming data with validation and transformation
  • Conditional Logic: Route execution based on data values or conditions
  • Iteration: Process arrays of data with loop nodes
  • Error Recovery: Handle failures gracefully with error handlers
  • Modular Workflows: Break complex logic into reusable sub-workflows

Branch Node

The Branch node evaluates conditions and routes execution to different paths.

Configuration:

  • Define one or more conditions using expressions
  • Each condition leads to a different output path
  • Default path for when no conditions match

Loop Node

The Loop node iterates over arrays or executes logic repeatedly.

Features:

  • Iterate over arrays with access to current item and index
  • Set maximum iterations to prevent infinite loops
  • Access loop context variables in child nodes

Error Handler Node

Catch and handle errors that occur in your workflow.

Configuration:

  • Wrap nodes that may fail
  • Define error handling logic
  • Access error details (message, code, stack trace)
  • Continue execution or fail gracefully

Nested Workflow Node

Execute another workflow as a sub-process.

Features:

  • Pass input data to child workflow
  • Receive output from completed workflow
  • Reuse common logic across multiple workflows
  • Maintain workflow modularity