Archflow vs OnUML

Archflow is a web platform for collaboratively designing software systems with AI. Its assistant can create architecture diagrams, user stories, scope cards, and technical documentation from natural-language input. The visual editor supports UML classes, interfaces, components, databases, and services, with drag-and-drop creation and undo/redo. Teams can edit together using synchronized changes, live cursors, presence indicators, comments, and activity feeds. Kanban boards track user-story status, estimates, and acceptance criteria, and link stories to architecture diagrams. Documentation is created in a Markdown editor with live preview and categories, and can also be AI-generated. The Free plan costs nothing and allows one project and three diagrams per project. Pro costs $5 a month and includes unlimited projects and diagrams, AI-generated content, real-time collaboration, and priority support. Archflow says prompts and selected project context are sent to OpenAI's API, and AI chat history is stored on its servers.

OnUML is a web-based AI diagram generator and UML editor for Mermaid, PlantUML, Draw.io and mind maps. It creates diagrams from natural-language prompts and supported image inputs, then supports visual or code editing with a real-time preview. A one-click repair tool addresses Mermaid and PlantUML syntax errors. Users can save multiple code versions, restore earlier content and organize diagrams by project. PNG and SVG export and shareable links are supported. Its remote MCP server connects with coding agents including Codex, Claude Code, Cursor and OpenClaw. MCP follows workspace permissions and can read or update Mermaid, PlantUML and OnUML mind maps; Draw.io is excluded. It checks for newer edits before updates and stops if an overwrite would occur. The Free plan costs nothing, billed forever, with two diagrams per project, ten cloud projects per workspace, two workspaces and ten free model requests daily. Paid choices include 4.90 USD and 9.90 USD one-time plans, a 19.90 USD one-time Pro Pack and Pro at $8 a month.