How long are virtual visa card valid for? Is there an end date?

Ethnio reward links never expire, but once anyone has activated the reward, the expiration is controlled by each payment provider. For example, if you select Amazon, those gift codes never expire. But prepaid credit cards always expire after a few months.

For all the prepaid card options you have 4 months to redeem their rewards and 7 months to use the cards after that.