ideone.com : Ideone is an online compiler and debugging tool which allows youto compile source code and execute it online in more than 60 programming languages.
repl.it : Powerful and simple online compiler, IDE, interpreter, and REPL. Code, compile, and run code in 30+ programming languages. including JavaScript, Pytho...
ack : ack is a tool like grep, optimized for programmers
Designed for programmers with large heterogeneous trees of source code, ack is written purely in po...
Favicon Generator : Upload an image (GIF, JPEG or PNG) and convert it to a Windows favicon (.ico)
Glicol : make music with code. connect different nodes like a synth, sequencer or sampler.
