Promo codes?

Does your built-in IAP system support promo codes?

I can create promocodes in the Google Developer Console. Then I want player to enter it in the game in IAP menu, in order to get a reward (gold coins, extra lives, etc.)
How can I send a request to GooglePlay server and check promo codes from Unity application?

Once you integrate In-APP it will support promo codes automatically.

To integrate In-Apps follow this official tutorial