How to distinguish SOAP protocol from REST and what are the main differences between them?

SOAP (Simple Object Access Protocol) is a message exchange protocol based on XML, with a strictly defined standard that supports advanced features such as security, transactions, and reliable message delivery. REST (Representational State Transfer) is an architectural style that uses standard HTTP methods (GET, POST, PUT, DELETE) and typically works with JSON or XML formats.

Main differences:

• Data format: SOAP uses only XML, REST can use XML, JSON, HTML, and others.
• Protocol: SOAP operates over HTTP, SMTP, and others, REST only over HTTP.
• Standards: SOAP is strictly standardized, REST is more flexible.
• Complexity: SOAP is more complex to implement and requires more resources, REST is simpler and lighter.
• Operation support: SOAP supports complex operations and extended features (e.g., WS-Security), REST is oriented towards CRUD operations on resources.

Example of calling a REST API in C#:

using System.Net.Http;
using System.Threading.Tasks;

HttpClient client = new HttpClient();
var response = await client.GetAsync("https://api.example.com/resource");
string content = await response.Content.ReadAsStringAsync();

For SOAP, a generated proxy class from WSDL is usually used.