We are going to interview some candidates over the phone and we need the candidate to write code (pseudo code). Obviously, asking the candidate to read the code out loud to us over the phone isn't ideal.
I wonder if there is any good platform to do this?
I know Facebook uses a simple program they wrote by themselves, and Google uses Google Doc. But unfortunately we don't have services by ourselves. Are there any good alternatives (other than Google Doc) that is open and free?
you could use Etherpad ( http://etherpad.com/ ) to see what exactly they are typing while they are typing it
Couldn't you use some IM client? Or are you really looking for something which is like a multi-cast notepad?
I've heard good things about EtherPad but haven't used it myself.
Generally I would look for something that:
EtherPad seems to satisfy all these requirements.
Failing that, I think you can actually glean a ton of good information in a phone interview without seeing written code. Candidates can describe pseudo-code and algorithms over the phone and being able to hold a solution in your head well enough to verbalize it is actually IMO pretty good signal about facility with programming & algorithms.
Another option is see[Mike]code which is great, no sign up process required, it just requires your email address to send you the URLs to go. They are valid for a month or so.