REST architecture constraints

Client-Server – Client and server are separated by a uniform interface and are not concerned with each other’s internal logic
Stateless – Each client request is independent and contains all the necessary information required to get executed. No client data is saved at the server.
Cacheable – Client should have the ability to cache the responses
Layered System – A layered system having multiple layers wherein each layer communicates with adjacent layer only
Uniform Interface – A uniform interface design requires each component within the service to share a single and uniform architecture
Code on Demand – This constraint is optional. It extends client-side execution of code transfer of executable scripts like javascript from the server.