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FlowFuse Application Guide

Node-RED Guide

Foundations

The handful of concepts you need to build with Node-RED, and how they fit together.

Foundations — start here

The handful of concepts you need to build with Node-RED, and how they fit together. You wire pre-built nodes into flows and spend your effort on the logic — what the system should do — while the platform handles the syntax and the connectivity. Learn these and you can build real integrations in Node-RED with only a little JavaScript — the structure carries most of the weight.

How it fits together

Node-RED runtime

Message in

http in / inject

Node

transform

Node

route

Sink

no routing

read / write state

Shared state

Context

shared state

  • msg travels the wires

A message enters a flow and passes from node to node, transformed along the way, until it reaches a sink that sends and routes nothing. Reuse comes from subflows and link nodes; shared state lives in context; new capabilities come from installing nodes off the palette.

The core pieces

Node

A single processing block: it receives a message, does one thing — read, transform, call, route — and passes it on.

Flow

Nodes wired left-to-right on a tab; a message enters, is transformed, and exits. One working unit of automation.

Message (msg)

The object that travels the wires, carrying msg.payload plus metadata between nodes.

Subflow

A block you define once and drop in many places, with its own inputs, outputs and per-instance config.

Link nodes

link in / link out / link call wire flows together across tabs with no visible wires — your in-process service calls.

Context

Storage that keeps state between messages — flow and global scope, in memory or persisted.

Palette

The library of installable nodes (npm) you add new capabilities from.

Editor & runtime

The browser editor where you wire flows, and the runtime that executes them continuously.

In the Node-RED docs

That's the working model. For the full glossary — every core term and node type, straight from the Node-RED project — see the official Node-RED documentation instead of a glossary here.

nodered.org/docs →