tldraw

tldraw is a free and instant collaborative whiteboarding application and React SDK created by Steve Ruiz, with funding from Sequoia Capital, Andreessen Horowitz, and Index Ventures. The platform combines a zero-setup multiplayer whiteboard accessible at its website with an embeddable software development kit that lets developers integrate an infinite canvas with drawing, shape, text, and media tools into any React application. The drawing toolbar provides twelve color options, four stroke styles including solid, dashed, and dotted, four size presets, three fill modes, and tools for freehand drawing, geometric shapes, arrows, text labels, sticky notes, image and video embeds, and frames for grouping related elements. The SDK exposes a custom shape API that allows developers to define interactive React components rendered directly onto the canvas, enabling domain-specific tools like database schema designers, flowchart builders, and UI mockup editors. Real-time multiplayer collaboration is powered by a WebSocket-based sync engine that handles cursor tracking, live shape updates, and conflict-free replicated data types for deterministic merge resolution. The tldraw editor is open source under the Apache 2.0 license, while the cloud collaboration API and hosted infrastructure are offered as commercial products. The canvas rendering engine uses a custom scene graph with incremental repainting and camera transformations, maintaining 60 frames per second with hundreds of shapes on screen. Additional features include undo and redo history, shape snapping and alignment guides, multi-page documents, exportable SVG and PNG images, and a plugin system for extending the default toolset.