Best Diagram Software for HTML

yFiles is a versatile library for graph and network visualization and analysis. It offers powerful rendering, editing, and automatic layout features for complex diagrams—including organizational charts, flowcharts, and IT infrastructures. With advanced layout algorithms and robust interactivity, yFiles helps developers build scalable, clear visualizations across web, desktop, and mobile platforms. Supporting HTML/JavaScript, Java, and .NET, it’s widely used in industries like telecommunications, finance, and life sciences to clarify complex processes and data relationships. yFiles is the most capable and mature graph visualization SDK available commercially. The company behind yFiles was founded in 2000. yWorks has brought together graph visualization techniques and algorithms from academia, making it available to software developers to integrate perfect diagramming into their applications.

Astah Professional helps software teams design systems visually, before and while they write code. One application covers UML 2.x, entity-relationship diagrams, data flow diagrams, flowcharts, requirement diagrams, CRUD matrices, and mind maps, so architects and developers do not have to switch tools between notations. Diagrams in Astah are views of a shared model. When you rename a class or change a relationship, every diagram that contains it is updated automatically. For AI-assisted work, Astah Professional offers AI Chat Copilot and AI-assisted code reverse engineering, both of which connect to OpenAI, Azure OpenAI, Claude, Gemini, or any OpenAI-compatible endpoint through your own API key. A local MCP server lets external AI agents work with your Astah models. Conventional reverse engineering of Java, C#, and C++ code works without an AI service. The tool runs locally on Windows, macOS, and Linux and ships with its own Java runtime. Developer: Change Vision, Inc. Current version: 12.0 (July 2026). A 20-day free trial is available.

Astah UML gives software teams and students a focused tool for UML 2.x modeling. Class, use case, sequence, activity, state machine, component, and deployment diagrams are all available, together with mind maps for early brainstorming. Every diagram is a view of a shared model, so renaming a class or changing a relationship updates it everywhere it appears. For AI-assisted work, Astah UML offers AI Chat Copilot and AI-assisted code reverse engineering, both of which connect to OpenAI, Azure OpenAI, Claude, Gemini, or any OpenAI-compatible endpoint through your own API key. A local MCP server lets external AI agents read and work with your models, and conventional reverse engineering turns existing Java, C#, and C++ code into diagrams without an AI service. Astah UML runs locally on Windows, macOS, and Linux. Developer: Change Vision, Inc. Current version: 12.0 (July 2026). Students can use it free of charge, and a 20-day trial is available for everyone else.

yEd simplifies the process of diagram creation, combining robust features with an easy-to-navigate interface, making it a delightful experience. This versatile desktop application allows users to swiftly and efficiently produce high-quality diagrams tailored to their needs. You can either create diagrams from scratch or import external data for a detailed analysis. With just a click, the automatic layout algorithms can organize even the most extensive data sets seamlessly. yEd also boasts a rich selection of attractive, pre-designed elements, providing an excellent starting point for new diagrams. Additionally, the application offers advanced capabilities for managing intricate data sets, thanks to its sophisticated mathematical layout algorithms that can assist in both automated and manual arrangements. Users will find that yEd not only enhances productivity but also empowers creativity in visual representation.