Eraser
Generate architecture diagrams, ERDs, cloud infrastructure diagrams, and sequence diagrams from natural language or code via DiagramGPT. Supports GitHub sync and a VS Code extension so diagrams stay connected to code. SOC II Type 2 compliant and never trains on user data.
Mermaid
Renders flowcharts, sequence diagrams, ER diagrams, C4 diagrams, and Gantt charts from simple Markdown-style text definitions. Native support in GitHub, GitLab, Notion, and dozens of engineering platforms. With 87k+ GitHub stars, it's the most widely adopted diagramming tool in engineering.