RapidChart

RapidChart is a web-based AI diagram generator for developers, students, software architects, and database designers who need technical diagrams without manual drawing.

Key capabilities include:

• Text-to-diagram and code-to-diagram generation for UML (class, sequence, use case, flowcharts), ER diagrams, and C4 models
• Intelligent auto-layout and an infinite canvas to organize large systems, workflows, and documentation
• Cloud architecture diagramming with support for AWS, Azure, and Google Cloud, plus AI and neural network visualizations
• Customization and sharing, plus custom API key support to use different LLMs (for example GPT-4 or Claude)

Pricing: Free (as of October 2025, core functionality is free to use).

Notable for combining natural language diagram creation with auto-layout on an infinite canvas, plus optional bring-your-own-model API keys for teams that want control over which LLM powers diagram generation.