GoJS

GoJS is a JavaScript library from Northwoods Software for building flowcharts, organisation charts, modelling diagrams and other interactive visualisations that run in a web browser. It is a developer tool rather than an end-user application: developers embed it in their own web applications to provide diagramming capability that would otherwise take many months to build. The distinction between GoJS and a charting library is important. Charting libraries render data as bars and lines; GoJS renders nodes and the links between them, and makes the resulting diagram interactive — users drag nodes, draw connections, resize, group, collapse and edit, with the library maintaining the underlying graph model and enforcing the rules the developer defines.

The library handles the genuinely difficult parts of interactive diagramming. Automatic layout algorithms arrange nodes sensibly without manual positioning, including tree, layered digraph, force-directed and circular layouts, which is essential when a diagram is generated from data rather than drawn by hand. Link routing computes sensible paths around obstacles with orthogonal, bezier and avoidance options. Templates define node and link appearance declaratively and bind them to a data model, so the visual representation updates automatically when the data changes. Interaction support covers selection, dragging, resizing, rotation, in-place text editing, drag-and-drop from palettes, context menus, tooltips, undo and redo, and copy and paste. Performance is engineered for large diagrams with virtualisation and incremental updates. Output includes SVG and image export and printing. The library is framework-agnostic and works with React, Angular, Vue and plain JavaScript, with TypeScript definitions provided. Extensive samples and documentation cover common diagram types including BPMN, state charts, genograms, network topologies, sankey diagrams and mind maps. Licensing is a one-time perpetual developer licence with no runtime or deployment fees, priced from around USD 995, with a fully functional evaluation available at no cost. Source-code and enterprise licences are available for teams requiring deeper customisation.