Try Eff online!

On the left-hand side, you see two text areas. The top one contains your source code, and the bottom one is the interactive toplevel. You execute the source code in the toplevel using the button between them. This web-based Eff toplevel is compiled using Js_of_ocaml and is very much based on the toplevel example included with Js_of_ocaml.

Load examples

Toplevel commands

Enter/Return Submit code
Ctrl + Enter Newline
Up / Down Browse history
Ctrl + l Clear display
Tab Indent code