noflo-ui, and the hosted version Flowhub uses a 'registry' of runtimes in order to remember runtimes a user has, across different machines and browsers.
The runtime registry is a simple HTTP RESTful service which can
list existing runtimes, register a new runtime and modify an existing runtime.
This here is an open source example of how to implement such a service.
npm install
npm start
See app.coffee