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It requires Ableton (there might be unofficial integrations with other DAWs). I have an Akai Force which is completely standalone, not even a computer needed. But I'd honestly recommend Ableton+Push unless someone really needs it to be standalone.

It's a MIDI controller, so in order for it to be useful it has to be connected to something that can accept MIDI inputs.

Not sure on how much use it is without Ableton, sorry - I'll need someone else to answer that