WebSocket vs. HTTP: Understanding Their Differences

WebSocket vs. HTTP, what are their differences? They are client-server communication protocols. While both protocols are based on establishing a TCP connection with a server, they differ significantly in terms of their capabilities and application modes. 

This article will assist in deciphering the fundamental characteristics of the HTTP and WebSocket protocols. The fundamental concepts behind their operation, their primary limits, and their primary distinctions will be explored. Additionally, you will discover whether WebSocket vs. HTTP is a better fit for specific use cases.

Defining HTTP

HTTP, or Hypertext Transfer Protocol, is a request-response protocol that is used to communicate between a client and a server, such as a web browser. The HTTP protocol is unidirectional, which means that the client initiates and maintains the connection with the server. 

This connection type is established when the client sends an HTTP or HTTPS request, and the server responds. In this case, the client is always the first to initiate communication with the server and request data. The connection is closed once the HTTP request has been fulfilled. A new request necessitates establishing a new connection with the server.

WebSocket vs. HTTP: From HTTP to WebSocket

Here is WebSocket vs. HTTP, in a nutshell. Despite advancements in recent HTTP versions, the HTTP protocol remains severely constrained in a number of ways. One of the primary problems of the HTTP communication protocol is that it is purely unidirectional, requiring the client to request all data from the server in the first place. The connection is terminated once the request has been fulfilled. This can be a significant impediment when a client requires regular updates from the server in real-time mode, for example. 

The invention and development of HTTP long-polling enabled a degree of circumvention of this constraint. Long-polling is a technique used by servers to extend the duration of the client-server connection, allowing for more time for new information to become available and sending back a response once the changes arrive. While the long-polling method works, it is inefficient on the server’s resources, especially when there is no data to relay. 

Additionally, the HTTP protocol has the limitation of allowing just one HTTP request to be sent over a single HTTP connection. The HTTP streaming approach was created to sidestep this constraint. It enables the server to provide an unspecified-length response for each HTTP connection. Even with this modification, the issue remains that an intermediary can still terminate the connection at any time. This means that it is still insufficient for real-time connection and communication.

Due to these constraints and the inability to overcome them through conventional means, a demand for a different mode of communication arose.

Defining WebSocket

As with HTTP, WebSocket operates on top of the TCP connection. While the HTTP protocol is completely unidirectional, imposing severe limits on communication, WebSocket is a bidirectional protocol that provides full-duplex communication. 

As a full-duplex bidirectional protocol, it enables both the client and server to send messages independently and without reference to a previous request. After establishing the connection, the client and server can communicate using the same TCP connection throughout the communication cycle. 

WebSockets are HTTP-based protocols that begin with ordinary HTTP queries and answers. The client requests the establishment of a WebSocket connection within this communication chain. If the request is successful, the client and server initiate a WebSocket connection using the TCP connection. From this point forward, data can flow via this connection until either the client or the server terminates it.