Open-source Concepts alternatives

tldraw is an SDK for building infinite canvas applications in React. It supplies a complete canvas engine that serves as the foundation for whiteboards, diagramming tools, design editors and other canvas products, and it ships a default whiteboarding tool set that you can use as is or replace with your own primitives.

Out of the box it offers pressure-sensitive drawing, geometric shapes, rich text, arrows with snapping, image and video support and image export. Developers can extend it with their own shapes, tools, bindings, interface components, side effects and event hooks, and can drive the canvas at runtime through the Editor API. Multiplayer collaboration is available through a self-hostable sync package, there are canvas primitives for building with LLMs, and the DOM-based rendering can embed websites such as YouTube, Figma and GitHub. It works in desktop and touch browsers.

Starter kits provide the custom shapes, tools and interface for common application types, and each kit is MIT licensed. The SDK itself is under tldraw's own license rather than a standard open-source one, so review the terms before shipping it in a commercial product.

Krita is a free and open-source cross-platform application for creating digital art from scratch. It is a digital painting program meant for artists who want to produce professional work from start to finish, and it is used by comic book artists, illustrators, concept artists, matte and texture painters, and the digital VFX industry.

It is built on the KDE and Qt frameworks. The GitHub repository is only a mirror, since the real code lives on KDE's invent.kde.org. The project offers a user manual at docs.krita.org, API documentation, a bug tracker, a community forum at krita-artists.org and an IRC channel where most developers can be found. Nightly builds for both unstable and stable branches are available from KDE's CI server.

Krita is written in C++ and licensed under GPL-3.0. The README includes a repository status table with feature and string freeze information for the current branch, and developer builds for Linux with debug symbols can be fetched from the CI system.