Get all space and its users

[mechaviper]

Is there a way where I can get a list of all spaces and its members in a certain site?

[streetturtle]

Could you please clarify what do you mean by 'Space'?

If site, then you can use following webscript which returns all member of site:

http://localhost:8080/share/proxy/alfresco/api/sites/<siteName>/memberships?size=250&nf=*&authorityType=USER‍