Hypertext Transfer Protocol principles :

1. Stateless :

• Each request from a client to a server is independent.
• The server does not retain any information about previous requests.

2. Request-Response Model :

• This model is based on the client initiating communication with the server.

3. Connectionless :

• After each request-response cycle, the connection between the client and server is closed.
• Connectionless => statelessness of HTTP

4. Text-Based :

• HTTP messages are human-readable.
• HTTP messages : headers and content

5. Uniform Resource Identifiers (URIs) :

• HTTP uses URIs (known as URLs) to identify resources on the WEB.

6. Methods :

• HTTP defines several request methods that indicate the desired action (ex : GET (retrieve data), POST (submit data), PUT (update date), DELETE (remove data))…

7. Status Codes :

• HTTP responses include status codes to indicate the outcome of the request.

  Les réponses informatives (100 - 199),

Les réponses de succès (200 - 299),

Les messages de redirection (300 - 399),

Les erreurs du client (400 - 499),

[Les erreurs du serveur](https://developer.mozilla.org/fr/docs/Web/HTTP/Status#réponses_derreur_côté_serveur) (`500` - `599`)

8. Stateless Cookies and Sessions :

• We can implement mechanisms like cookies and sessions to maintain state and user sessions across multiple HTTP requests.

9. Extensible :

• Allows flexibility and the addition of new feautures or functionality (Custom headers for example can be defined by developers to carry specific data or instructions)

10. Caching :

• HTTP supports caching meachinsms (allowing clients to store and reuse responses from the server to reduce latency and bandwidth usage).