The main difference between the views of Piaget and Vygotsky in their perspectives of the nature of development and intelligence lays in their opinions as to what comes first: Development followed by learning, or development through learning.
In Piaget's theory he ascertains that, before the process of learning begins, the individual has to be developmentally ready. In other words, Piaget gives emphasis to age, maturity, and physical development and considers them essential for learning. Age supersedes learning. You can only learn things once you hit a certain age. This is why, today, we divide children by age groups to determine which grade they will be in.
Vygotsky, on the other hand, understands that development occurs in tandem with learning. In other words, you learn and develop as you go. Once you get enough social contact, you will begin to develop quicker and more effectively through the interaction with others. The way we apply Vygotsky in the classroom is by making cooperative learning groups. While Piaget's theory is still popular for grouping children together by age, Vygotsky's is applied through the use of differentiated learning for scaffolding within those same groups.
Yet, there is a similarity between Piaget and Vygotsky, and it is that the both agree that there is a prime developmental moment for optimal learning. Whether it comes prior or during the learning occurs is what sets them apart.