Open Source Diagram Editors

Excalidraw is an open-source whiteboard tool that lets you easily sketch diagrams that have a hand-drawn feel to them. Available directly online as a web app and also through CodeSandbox to easily see how the code works, and the app is available for self-hosting.

Draw lets you produce anything from a quick sketch to a complex plan, and gives you the means to communicate with graphics and diagrams. With a maximum page size of 300cm by 300cm, Draw is a an excellent package for producing technical drawings, general posters, and much else.

Pencil is a standalone app that lets you create diagrams or UI mockups. It doesn't have collaboration/multi-user features.

Open-source diagram editor with cross-platform support offering entity relationship, UML, flowchart, and network diagram creation with editable objects.

DeepNotes is an open source, end-to-end encrypted visual note-taking app with deep page navigation and live collaboration. Create mind maps, diagrams, kanban boards, among others. Infinite nesting of infinite canvases.

Ever wanted to simplify documentation and avoid heavy tools like Visio when explaining your code? This is why mermaid was born, a simple markdown-like script language for generating flowcharts, Gantt charts and sequence diagrams from text via JavaScript.

PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others.

Powerful web-based editor for creating detailed commutative diagrams, exporting them to LaTeX with embedded links for easy sharing and re-editing.

tldraw is a collaborative digital whiteboard available at tldraw.com. Its editor, user interface, and other underlying libraries available in this repository and also distributed on npm. You can use tldraw to create a drop-in whiteboard for your product or as the foundation on...

Graphviz is open source graph visualization software. Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks. It has important applications in networking, bioinformatics, software engineering, database and web design...

Lorien is an infinite canvas drawing/note-taking app that is focused on performance, small savefiles and simplicity. It's not based on bitmap images like Krita, Gimp or Photoshop; it rather saves brush strokes as a collection of points and renders them at runtime (kind of...

Creates diagrams from textual descriptions! It provides a unified API with support for BlockDiag, BPMN, Bytefield, C4 (with PlantUML), Ditaa, Erd, GraphViz, Mermaid, Nomnoml, PlantUML, SvgBob, UMLet, Vega, Vega-Lite, WaveDrom.

Umbrello is a Unified Modelling Language (UML) modelling tool and code generator. It can create diagrams of software and other systems in the industry-standard UML format, and can also generate code from UML diagrams in a variety of programming languages.

Simple web based ascii flow diagram drawing tool, draw boxes, lines, arrows and type, then export straight to text/html.

Gaphor is a WYSIWYG (What You See Is What You Get) UML and SysML modeling environment easy to use that will help you create your applications.

Heimer is a desktop application for creating mind maps and other suitable diagrams. It's written in Qt and targeted for Linux and Windows.

Penrose is a platform that enables people to create beautiful diagrams just by typing mathematical notation in plain text. The goal is to make it easy for non-experts to create and explore high-quality diagrams and provide deeper insight into challenging technical concepts.

A daily drawing tool that supports low code for learning or office use. It can be used for flowchart, mind map, UML diagram, ER diagram, network topology diagram, BPMN, Venn diagram, database model diagram, whiteboard drawing, infinite canvas, and more.

Open source wireframing tool written in typescript, react and redux.

Azimutt is an explorer for your database schema, similar to an Entity Relationship Diagram (ERD) but with features to handle big schema (up to 1000 tables) where most other ERD are too crowded.

UMLet is an open-source UML tool with a simple user interface: draw UML diagrams fast, export diagrams to eps, pdf, jpg, svg, and clipboard, share diagrams using Eclipse, and create new, custom UML elements.

Open source editor for instant database diagrams from a single query, quick schema visualization, AI-powered DDL export, and SQL/image sharing in 15 seconds.

Drawy is a work-in-progress infinite whiteboard tool, which aims to be a native desktop alternative to the amazing web-based Excalidraw.

Simple schematic/diagram editor with focus on quick diagram generation with high quality graphics.

MonoSketch is a powerful ASCII sketching and diagramming app that lets you effortlessly transform your ideas into visually stunning designs.