Eraser vs OnUML

Eraser is a diagramming tool for technical teams that generates diagrams from prompts, code, files, and private Git repositories. It supports flow charts, entity-relationship diagrams, cloud architecture diagrams, sequence diagrams, and BPMN diagrams. Generated diagrams can be adjusted with diagram-as-code or AI edits, and reference libraries can align output with company building blocks. Collaboration includes real-time work, comments, tagging, and unlimited free guests. The service lists GitHub, Notion, Confluence, and a VS Code extension, as well as live diagram embeds and Git-powered updates. The free plan includes 3 files, 3 AI diagrams, and 7-day version history. Starter costs $15 a month when billed annually, or $20 monthly; it adds unlimited files, private files, and API calls. The diagram API is for paid users, while MCP operations are subject to plan AI-credit limits. Eraser says it is SOC 2 Type 2 certified, performs annual penetration testing, and does not train AI models on customer content. Enterprise deployment options include multi-tenant, single-tenant, and self-hosted setups.

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.