Ask HN: Best way to donate my dev skills?

I have been wanting to contribute my time and skills to some charitable organizations and/or worthy causes lately. I feel like this could make a larger impact than, say, just throwing money at causes I believe in and hoping that those people do something other than give themselves a pay bump with it or some corrupt dictator buy himself a new gold helicopter.. The problem is that I have _zero_ idea where to start. For the time being I just want to dip my toe in the water so to speak to see how things go. I have a family so I only have so much extra time to give. My main areas of expertise lie in JavaScript/NodeJS but have a ton of experience in a lot of other parts of the stack and am comfortable working with languages like PHP. Are there organizations out there that are in dire need of someone with good web development skills?