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Connecting Nodes

Nodes communicate through edges — connections drawn between their ports. This guide explains how connections work, port types, data type compatibility, and the difference between data and trigger edges.

How Connections Work

To connect two nodes, click and drag from an output port (right side of a node) to an input port (left side of another node). Release the mouse to create the edge.

Drawing an edge between nodes

Port Types

Each node has ports on its left (input) and right (output) sides.

Port types close-up

Input Ports (Left Side)

Port Purpose
Trigger Controls whether the node executes
Named data ports Receive specific values (e.g., message, data, text)
Unified input Accepts all inputs as a single JSON object

Output Ports (Right Side)

Port Purpose
Trigger Signals that the node completed execution
Named data ports Emit specific output values
Unified output All outputs combined as a single JSON object
Branch ports Gateway nodes only — named branches like True / False

Data Types and Colors

Ports are color-coded by data type. Matching colors means matching types.

Data Type Color Aliases
String Emerald text
Number Blue integer, float
Boolean Purple
Array Amber list
Object Orange json
Mixed Orange
URL Cyan email
Date Lime datetime, time
File Red document
Image Pink picture
Trigger Dark gray

Connection Rules

The rule is simple: same type connects to same type.

  • string connects to string
  • number connects to number
  • string[] connects to string[]
  • And so on.

If you need to convert between types, use a processing node in between. For example:

  • String to number → Use a DataShaper or processing node
  • Object to string → Use a DataExtractor node
  • Single value to array → Use an appropriate conversion node

Tip

If you cannot connect two ports, check their data types (look at the colors). You may need a conversion node in between.

Data Edges vs Trigger Edges

FlowDrop has two kinds of edges that serve different purposes:

Data edge vs trigger edge

Data Edges

Data edges carry values between nodes. When a node finishes executing, its output data flows through data edges to the connected nodes' input ports.

  • Connect from a data output port to a data input port
  • The data type of both ports must be compatible
  • Multiple data edges can feed into the same node

Trigger Edges

Trigger edges control execution flow. They determine if and when a downstream node executes.

  • Connect from a trigger output port to a trigger input port
  • Used primarily with gateway nodes to create conditional paths
  • A node with a trigger input will only execute when it receives a trigger signal

Gateway Nodes and Branches

Gateway nodes (IfElse, SwitchGateway, BooleanGateway) create branching logic. They evaluate a condition and activate one or more output branches.

Gateway node with branch ports

For example, an IfElse node has:

  • One input for the value to evaluate
  • A True branch output port
  • A False branch output port

Only the nodes connected to the active branch will execute.

Tips

  • Port colors guide you — If the colors match, the connection is valid.
  • Use unified ports for flexibility — The input and output ports accept/emit all data as a single JSON object, useful when you need maximum flexibility.
  • Gateway diamonds create branches — Look for the diamond shape to identify branching points in your workflow.
  • One output to many inputs — A single output port can connect to multiple input ports, fanning out data to several nodes.

Next Steps