rainbow-delimiters.el:

Rainbow Delimiters is a “rainbow parentheses”-like mode which highlights parentheses, brackets, and braces according to their depth. Each successive level is highlighted in a different color. This makes it easy to spot matching delimiters, orient yourself in the code, and tell which statements are at a given depth.

Great care has been taken to make this mode fast. You shouldn’t see any change in scrolling or editing speed when it's on even when working in delimiter-rich languages like Clojure or Emacs Lisp. It can be used with any language.

You can customize the colors rainbow-delimiters uses. The default colors are intentionally subtle; they are unobtrusive enough to make the mode worth looking at even if you usually don’t like rainbow parentheses modes. A number of major color themes such as Zenburn and Solarized have added their own faces for the mode.

This is the official github repository for rainbow-delimiters.

The latest release of rainbow-delimiters.el is always found here:

• rainbow-delimiters.el

Further information is available on the EmacsWiki page:

• http://www.emacswiki.org/emacs/RainbowDelimiters

Installation instructions:

1. Place rainbow-delimiters.el on your emacs load-path.

2. Compile the file (necessary for speed):
   M-x byte-compile-file [location of rainbow-delimiters.el]

3. Add the following to your dot-emacs/init file:
   (require 'rainbow-delimiters)

4. Activate the mode in your init file.

• To enable it only in certain modes, add lines like the following:
  (add-hook 'clojure-mode-hook #'rainbow-delimiters-mode)

• To enable it in all programming-related emacs modes (Emacs 24+):
  (add-hook 'prog-mode-hook #'rainbow-delimiters-mode)

• To toggle rainbow-delimiters mode in an open buffer:
  M-x rainbow-delimiters-mode

Additional discussion is at the top of the file and on the EmacsWiki page linked to above.