There are 3 platforms. Two Java based: one for "manual trading" and one for "automated trading". You can use EAs, custom indicators etc. in the latter, but in Dukascopy's own language (Java with theirs API in fact). Works well. There is even conversion tool from MT4, but sometimes it doesn't work well. You can find some natively written EAs, but far fewer, than for MT4 of course.
I use the Java "automated trading" platform, to trade manually
I like the interface best.
Third platform is web-based. I didn't use that one, so don't know how good it is. And MT4 platform is in beta - not finished yet.
Oh, there is also very good&sweet little platform for iPhone. I used it on many occasions to monitor, close or partially close my positions, move SLs etc. when I couldn't sit at my computer. There are even charts, news, pivot points, reports, etc. there. Definitely recommended. But nothing beats 26" monitor when it comes to real trading of course. Or two even
You can trade as low as 1k of currency unit (microlot), no matter how big your account is.