Is tunnel.pyjam.as safe?

I am wondering if nextcloud using tunnel.pyjam.as is safe and if thay can access my nextcloud files. Thank you

They have it SSL terminated, but then the connection between them and you is just http, so they can see all unencrypted transferred data. For me it looks more like something where you can run a test with uncritical data but you don’t want a service or your data rely on that.