The simple mode for GNU/Emacs for setting up local Go language playground with features similar (and with help of go-mode even outperform!) service at play.golang.org. You may treat it like the simple REPL for Go. This is not a wrapper for working with play.golang.org from Emacs (it is already did by original go-mode), this is complete alternative for setting local playground inside Emacs without using browser for experiments with code snippets. Web playground at play.golang.org is a nice idea. It has not require setup and it executes your code in a restricted environment where you can't damage you system. But it brings many restrictions too especially when you want use additional helpers for working with your code: formatters, code completers etc. Emacs offers many such tools for Go development so it is the most comfortable play with snippets inside Emacs instead of rude webeditor. Of course local playground requres you to setup Go environment but if you developing in Go (or you want to do it) you are anyway would need to setup go-mode and helper tools for working with code in a comfortable way.