Good news for all fans of the BBC Micro and those who want to risk to become one: There’s another web-based emulation platform, specifically targeted at programming, the Owlet Editor (currently in beta):
A simple, modern editor for BBC BASIC inspired by BBC Micro bot
Any BASIC input can be immediately run in the web-site, but there are also links to forward it to jsbeeb for a richer emulation or to send it as a tweet to BBC Micro bot.
The source code can be found on GitHub: https://github.com/mattgodbolt/owlet-editor
Via HN, discussion: BBC Basic Editor | Hacker News