Browser IDE: A Full Development Environment in Your Browser

[Juice10]

What: Create a secure, sandboxed environment accessible from any browser—no local setup required.
Why: Make coding instantly available to anyone with a web connection, significantly lowering the friction of installing or managing local software.
Questions:
Which frameworks or libraries are best for in-browser IDE experiences?
How do we handle file management, authentication, and data storage?
Are there performance challenges when dealing with large codebases or resource-heavy tasks in-browser?
Looking for input on user experience, platform limitations, and security considerations.