Some of you have tried the J guest server and have provided good feedback.
I am surprised (disappointed) that no one has tried the facility that allows your files to be carried forward from one guest session to the next.
If interested, please try the following:
*** start a guest session
https://server.jsoftware.com:65101/jguest jgp'...' NB. ... is your private name for your persistent storage
'a=: 6' fwrite '~temp/test.ijs'
esc-q to end the session
your guest ~temp folder is saved to your private name
*** start new guest session
https://server.jsoftware.com:65101/jguest jgp'...' NB, private name you used above
fread'~temp/test.ijs'
***
This is documented in ☰.help.guest files