Chatuml - 2026 Pricing, Features, Reviews & Alternatives

Chatuml is a cloud-based, browser-based AI diagram generator that converts natural language instructions into PlantUML diagram code through a conversational chat interface. Targeting individual developers, software architects, and technical teams, it removes the requirement to write PlantUML syntax manually. Users describe diagrams in plain text, and the AI assistant generates, iterates, and refines the output across multiple conversational turns. Supported diagram types include UML, flowchart, network, C4, sequence, and activity diagrams. The platform supports multiple large language models (LLMs), including GPT-4o, GPT-4o Mini, GPT-4 Turbo (128k context), GPT-4 (8k context), and GPT-3.5 Turbo 16k, allowing users to select models based on diagram complexity and token requirements.

Beyond text-based generation, Chatuml accepts up to three pasted images per chat session, such as whiteboard sketches or hand-drawn diagrams, which the AI interprets and converts into structured PlantUML output. URL-based link ingestion allows the AI to pull in text content from external sources as conversation context, reducing manual copy-paste steps. Full conversation history is preserved and passed to the model throughout each session, maintaining context across iterative refinements. Advanced users retain direct access to the underlying PlantUML code through an integrated code editor, with an AI-assisted command input box available for targeted code modifications. Diagram output supports zoom, pan, and export to multiple formats.