Terms and Definitions
The fundamental building blocks of React Flow include nodes, edges, handles, a connection line and the viewport. Let’s examine each of these core elements in more detail.
Nodes
React Flow comes out of the box with a few default node types, but customization is where the magic of React Flow truly happens. You can design your nodes to work exactly the way you need them to—whether that’s embedding interactive form elements, displaying dynamic data visualizations, or even incorporating multiple connection handles. React Flow lays the foundation, and your imagination does the rest.
We have a guide on creating your own Custom Nodes. You can find all the options for customizing your nodes in the Node Options documentation.
Handles
A handle (also known as a “port” in other libraries) is the attachment point where an edge connects to a node. By default, they appear as grey circles on the top, bottom, left, or right sides of a node. But, they are just div elements, and can be positioned and styled any way you’d like. When creating a custom node, you can include as many handles as needed. For more information, refer to the Handle documentation.
Edges
Edges connect nodes. Every edge needs a target and a source node. React Flow comes with four built-in edge types : default (bezier), smoothstep, step, and straight. An edge is SVG path that can be styled with CSS and is completely customizable. If you are using multiple handles, you can reference them individually to create multiple connections for a node.
Like custom nodes, you can also customize edges. Things that people do with custom edges include:
- Adding buttons to remove edges
- Custom routing behavior
- Complex styling or interactions that cannot be solved with just one SVG path
For more information, refer to the Custom Edges Reference page.
Connection Line
React Flow has built-in functionality that allows you to click and drag from one handle to another to create a new edge. While dragging, the placeholder edge is referred to as a connection line. The connection line also comes with four types built in and is customizable. You can find the props for configuring the connection line in the props section .
Viewport
All of React Flow is contained within the viewport. Each node has an x- and y-coordinate, which indicates its position within the viewport. The viewport has x, y, and zoom values. When you drag the pane, you change the x and y coordinates. When you zoom in or out, you alter the zoom level.