Introduction : 

Representational State Transfer (REST) is an architectural style for designing web-based applications. RESTful APIs (Application Programming Interfaces) use HTTP (Hypertext Transfer Protocol) to exchange data between client applications and servers. RESTful APIs rely on a set of constraints to operate, including a uniform interface, client-server architecture, statelessness, and a layered system, which ensures scalability, flexibility, and simplicity. 

RESTful API Architecture:

1. Client-Server Architecture: In a RESTful API, the client and server are separated into distinct layers. This separation allows for better scalability and flexibility.

2. Statelessness: RESTful APIs are stateless, meaning that each request contains all the information necessary to complete the request. This allows for better scalability and performance.

3. Cacheability: RESTful APIs are designed to be cacheable, which can improve performance by reducing the number of requests that need to be made to the server.

4. Layered System: RESTful APIs are designed to be layered, with each layer providing a different level of abstraction. This allows for better scalability and flexibility.

5. Uniform Interface: RESTful APIs use a uniform interface, which consists of a set of HTTP methods (GET, POST, PUT, DELETE, etc.) and resource representations (JSON, XML, etc.). This promotes simplicity and ease of use.

HTTP Methods:

The HTTP methods used in RESTful APIs are used to perform operations on resources. The most commonly used methods are:

1. GET: Retrieves a resource from the server.

2. POST: Creates a new resource on the server.

3. PUT: Updates an existing resource on the server.

4. DELETE: Deletes a resource from the server.

Resource Representation:

The resource representation is the format used to represent the resource being accessed or manipulated. The most commonly used formats are JSON and XML. 

Endpoints and URIs:

RESTful APIs are accessed through endpoints, which are represented by URIs (Uniform Resource Identifiers). A URI is a string of characters that identifies a resource on the web.

https://personal-wybzdceu.outsystemscloud.com/API_CS/rest/RESTAPI/

Security:

Security is an important consideration when designing RESTful APIs. There are a number of security measures that can be taken to protect against attacks, including:

1. Authentication: requiring clients to provide credentials to access the API.

2. Authorization: controlling what actions a client can perform on a resource.

3. SSL/TLS: encrypting the communication between the client and server.

4. Rate Limiting: limiting the number of requests that can be made