Specification pattern is a design pattern that allows to encapsulate some pieces of domain logics into a single unit, that can be passed around the system. It's a way to take some conditional logic and put it into a reusable, composable unit.
It is important to have a good understanding of the Repository pattern and the Specification pattern in Entity Framework Core.
In its typical form, a specification is composed of one or more criteria, allowing entities to be filtered based on these criteria. Additional properties like sorting and pagination can also be incorporated. Here's a basic implementation of a Specification class.