Developers want better ways to sketch software designs alongside their code. IDE extensions that create interactive whiteboards could bridge this gap.
Build VS Code/IntelliJ plugins that render flowcharts from comments or special syntax. Offer free basic version with paid advanced features.
Start with simple box-and-arrow diagrams generated from Markdown. Later add real-time collaboration.
The risk is competing with built-in tools from major IDEs. Focus on niche visualization types first.