Web-Playgrounds (extern):
coding.seriousIT.de
coding.GodfatherIT.de
Mix:
David Beazley
Dylan Beattie
Github
W3Schools
HTML/CSS/PHP:
selfhtml
php-einfach
php.net
Perl:
Perl Home
Python:
python.org
A Byte of Python
Python-Kurs
RealPython
OS X/iOS:
Apple Developer
iTunes Connect
Cocoa-Coding
UIKit Reference
Swift Language
Arduino:
Arduino Home
funduino
Raspberry:
Raspberry Home
BerryBase