Which kind of caterpillar is this?
Based on the body structure and double pair of legs per body segment, this is a millipede. 

Based on the small size and spacing between body segments, it could possibly be in the Paradoxosomatidae family. You could check by examining the specimen more closely:


  Most species possess a groove or furrow ("sulcus") on the dorsal surface between the keels (paranota) on each segment.


Although the color is wrong, this millipede reminds me of the somewhat-cosmopolitan invasive, the Green house millipede (Oxidus gracilis), which is about 1.8 to 2.3 mm long. 



 Source: NCSU Plant Disease and Insect Clinic; Credit: Matt Bertone 

Due to the color difference, I cannot tell definitively whether this is your species or not. Your poor picture quality makes this more difficult. However, I thought I'd provide this post for you as a jumping off point. good luck!