Let's have a look at the ICs on the logic board:

Samsung K4E8E304EE-EGCE 8 Gb LPDDR3 DRAM (8 Gb x 4 = 32 Gb = 4 GB)

Unfortunately, the RAM is soldered to the logic board. This means that if you want to upgrade the RAM, you can only do so at time of purchase.

Cirrus Logic 4208-CRZ Audio Codec (a returning champion from a bevy of recent Apple products including the Mid 2013 MacBook Air and Mac Pro)

Broadcom BCM57766A1KMLG Ethernet PCIe Controller with SD3.0 Card Reader and ASF 2.0

Intel DSL5520 Thunderbolt 2 Controller

Delta Electronics LFE8904C-F Discrete LAN Filter

NXP 6142F and NXP PCA9501BS 8-bit I/O Expander