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Hypertext Markup Language (HTML)

  • A text-based approach to describe how content contained within an HTML file is structured.

Hypertext Transfer Protocol (HTTP)

  • It enables communications between clients and servers.
  • It works as a request-response protocol between a client and server.

Anatomy of an HTTP request

  • An HTTP request must have the following:
    • An HTTP method (like GET)
    • A host URL (like
    • An endpoint path (like v1/artists/{id}/related-artists)
    • Optional:
      • Body
      • Headers
      • Query strings
      • HTTP version

Anatomy of an HTTP response

  • A response must have the following:
    • Protocol version (like HTTP/1.1)
    • Status code (like 200)
    • Status text (OK)
    • Headers
    • Optional:
      • Body

HTTP methods

  • POST, PUT, PATCH, and DELETE can change data on the server.

1. GET

  • It requests data from a specified resource.

  • Query string (name/value pairs) is sent in the URL of a GET request.

  • It reads or retrieves a resource.

  • A successful GET returns a response containing the information you requested.

  • In a weather app, GET retrieves the current weather for a specific city.


  • It creates a new resource.

  • It requires a body in which you define the data of the entity to be created.

  • A successful POST request would be a 200 response code.

  • In a weather app, POST adds weather data about a new city.

  • POSTing multiple times would create multiple separate orders.

3. PUT

  • It updates the entire resource with data that is passed in the body payload.

  • If no resource matches the request, it will create a new resource.

  • In a weather app, PUT updates all weather data about a specific city.

  • Multiple PUT requests will update the same existing order.


  • It is like GET without the response body.


  • It deletes the specified resource.

  • In a weather app, DELETE deletes a city we no longer wanted to track for some reason.


  • It modifies a part of a resource.

  • You only need to pass in the data that you want to update.

  • In a weather app, PATCH updates the rainfall for a specified day in a specified city.


  • It describes the communication options for the target resource.


  • It starts a two-way communication (a tunnel) with the requested resource.


  • It performs a message loop-back test that tests the path for the target resource (useful for debugging purposes).

Secure Shell (SSH)

  • A network protocol that gives users, particularly system administrators, a secure way to access a computer over an unsecured network.

Transmission Control Protocol (TCP)

  • TCP and IP are the basic rules that define the Internet.
  • TCP is a standard that defines how to establish and maintain a network conversation by which applications can exchange data.
    • It determines how to break application data into packets that networks can deliver.
    • It sends packets to and accepts packets from, the network layer.
    • It manages flow control.
    • It acknowledges all packets that arrive.
    • It handles the retransmission of dropped packets, as it’s meant to provide error-free data transmission.

User Datagram Protocol (UDP)

  • It reduces latency and jitter by not reordering packets or retransmitting missing data.
  • It discards invalid data packets.