https://www.spark.io/build is great IDE, but you may want to use your own tool, which is Emacs :) Open your .emacs and associate .ino file to cc-mode. (setq auto-mode-alist (append '(("\\.h$" . c++-mode) ("\\.cpp$" . c++-mode) ("\\.ino$" . c++-mode)) auto-mode-alist)) When you are using Emacs, you need to compile & flash via console. Don’t worry it’s easy! % brew install node % npm install -g spar