You can try out Clowder using the demo site below. You will have to create an account and wait for an administrator to approve your account. Please use an institutional email address (university or company) if you can. If not you will be asked some basic questions on your affiliation in an email. You will then be given access to the site.
This demo site has basic functionality enabled and it’s mostly a way to view the basic web interfaces. It can also be used to test the API. Please don’t rely on this instance to store the only copy of your data. Data on this site can and will be erased periodically.