I'd get 8GB, I do have trouble now and then with the 4GB, but only because of the VM (I have to reboot), 8GB will give you a longer lifetime I think (I didn't think you could upgrade the RAM in the mini's any more).
Mac mini (Late 2014)
Mac mini (Late 2014) does not have user-installable RAM. You can configure the memory in your Mac mini (Late 2014) when you purchase it.
Yes. I just saw that. I cant reply to your comment directly as there is no reply button below your comment (probably nested too deep). stackexchange might be a good place to check. I think the 2012 mac mini was eating into their higher end machine sales and crippling the 2014 mac mini is move on their part to counter this.
oh, I just had a look and the base model doesn't have an SSD - I'd really not consider developing without an SSD any more. It will work but compile times are slower, how much I couldn't say. But then I've developed for years without an SSD before that so...
That's why I thought of 16Gb Ram. I'm thinking, The whole of XCode and the compiler and my program source would be in the buffer cache. So after the initial loading from disk, the dev experience would be quite smooth (that's the guess I'm making).
In the memory section, it says it's upgradeable.
And I think this is a link from Apple's own instructions on how to do the upgrade.
https://support.apple.com/en-is/HT4432