Explorus Interface
Explorus is a full consensus explorer and light block explorer by Functori. It is very useful to monitor what is happening on any Tezos blockchain, and in particular a sandbox blockchain for which you have no out of the box explorer. Simply open https://explorus.functori.com/, go to the dented wheel on the top right corner, and enter the URL of your sandbox node. If you are using a default Flextesa setup, this will be http://localhost:20000.