From the homepage:

Thinking in services

Jolie crystallises the programming concepts of service-oriented computing as linguistic constructs. The basic building blocks of software are not objects or functions, but rather services that can be relocated and replicated as needed. A composition of services is a service.

Tailored for microservices and APIs

Jolie is a contract-first programming language, which puts API design at the forefront. It supports both synchronous and asynchronous communication. Data models are defined by types that support refinement [...], and DTO (Data Transfer Objects) transformations are transparently managed by the interpreter.

From vision:

Our vision is to design a programming language with a different trade-off: instead of optimising for computation, the aim of Jolie is to offer native abstractions for the creation and composition of services.

By shifting the focus on services from libraries and frameworks to the programming language, we can change significantly how programmers manage their knowledge regarding service programming. The key idea is that the important abstractions for service programming should be crystallised in the programming language, translating to an easier learning curve for new service developers and less knowledge to be managed.