WebSocket and HTTP are both computer communication protocols that operate on the TCP layer to enable communication between clients and servers. Although both protocols operate at the TCP layer, they have distinct capabilities and application modes, with notable differences between them.

In this article, we will discuss about key features of the HTTP and WebSocket protocols. How do they work, what are their benefits, and their major differences? 

What is the HTTP Protocol?

HTTP, or Hypertext Transfer Protocol, is the fundamental protocol for transmitting data on the web, enabling clients (like web browsers) to request and receive resources from the servers, such as web pages, images, and videos.

It works like a request-response protocol. The client sends a request to the server, which can be GET for data retrieval or POST for sending data. In return for the request, the server sends a response indicating the outcome of the request with status codes.

Note: The client will always initiate the connection request with the server, and it is unidirectional means requests can only be sent by clients. 

How Does the HTTP Protocol Work?

The HTTP protocol was designed as a request-response protocol. A client, such as a web browser, would send a request to a web server, and the web server would reply with a response containing the resources corresponding to the request, such as HTML and CSS files.

While HTTP connections are open, they are only half-duplex means the communication is only one way. Once a response has been received, the connection is immediately closed. That means, if the client sends 4 HTTP requests, 4 separate connections have to be made.

The main steps of an HTTP session can be described as:

• The client sends the request to the server. This action allows the client to establish a connection with the server by sending it a SYN (Synchronize Sequence Number) data packet.
• The server in the back sends the response to the client. The main goal of this message is to confirm on the server side that it has received the packet and the connection is now being used to provide the resources requested by the client.
• After receiving the required information and the ACK packet from the server, the client responded with an ACK packet to confirm the receipt of the response from the server.

After this message, the connection closes.

Each HTTP protocol request consists of the following information.

• A request line that includes methods (GET/POST, etc.) and the HTTP protocol version, like HTTP/1.1 or HTTP/2.
• An HTTP header 
• An optional message to the server where the request is being transmitted.

What are the Types of the HTTP Protocol?

These are two famous versions of the HTTP protocol

HTTP/1.1

It is way more advanced than the basic version of the HTTP protocol. It is the most compatible version, and it works with most browsers and servers.

It is an upgraded version of the HTTP protocol, because it authorizes both pipelined and uniform connections, a new range of header fields for both requests and responses, and dynamic communication in real-time.

HTTP/2

HTTP/2 is a major update to HTTP that enhances web performance by enabling multiplexing (multiple requests/responses on a single connection), using a more efficient binary protocol instead of text, compressing headers with HPACK, and allowing the server push of resources. It also introduced stream prioritization and requires TLS encryption for security.

Limitations of the HTTP Protocol

The HTTP protocol is the simplest and most lightweight protocol, but it comes with some limitations:

• No Encryption: HTTP transmits data in plain text, making it readable to unauthorized parties.
• Data interception: Attackers and hackers can intercept data during transmission, including sensitive information like passwords or credit card numbers.
• MITM (Man-in-the-middle) attacks: Without encryption and authentication, users can’t be sure if they are communicating with a legitimate server, making them vulnerable to attacks where a malicious user can intercept and alter communication and data.
• Limited Functionality: More modern web APIs, browser features, and critical payment gateways require HTTPS, restricting the functionality available to an HTTP-only website.
• Lack of Authentication: HTTP does not verify the identity of the server, making it difficult for users to ensure they are connecting to the correct website.
• Head-of-Line Blocking: The HTTP/1.1 protocol can experience delays, where one slow or large response can block other responses, drastically slowing down the performance.

What is the WebSocket Protocol?

WebSocket is a communication protocol that provides a persistent, full-duplex communication channel between a client and a server over a single, long-lived TCP connection.

Unlike HTTP requests, which are unidirectional and create a separate connection for each request, WebSocket allows both the client and server to send data to each other at any time, enabling real-time, bidirectional communication. This makes it ideal for applications like live chat, online gaming, and financial trading platforms.

Full-duplex bidirectional communication means that both the clients and the servers can push messages in both directions. Once the connection is established, the client and the server can communicate via the same TCP connection throughout the entire communication cycle.

How Does WebSocket Work?

When the WebSocket protocol starts the connection, it acts as a standard HTTP protocol. In this communication chain, the client requests to open a WebSocket connection. If the request is successful, new data can be sent and received from both sides until it is shut down by either the client or the server.

So, the upgrade of the HTTP connection to a WebSocket connection is called an opening handshake.

Each WebSocket session can be broken into these steps:

• When you make a WebSocket connection, it follows the same steps as an HTTP request, with an additional request asking, “Hey! Do you support WebSockets?”
• If the server responds “Yes”, the HTTP connection is upgraded to a WebSocket connection.
• Once the connection is established, both the client and the server can transmit and receive data in real-time until either party decides to close the connection.

What are the Advantages of WebSocket

The key advantages of the WebSocket protocol are:

• Real-time, Bidirectional Communication: Unlike traditional HTTP, where the client has to initiate every request, WebSockets establish a single connection that allows both the client and server to send data to each other simultaneously.
• Low Latency: By maintaining a full-duplex connection, WebSockets eliminate the overhead of repeated HTTP headers and connection handshakes.
• Encryption: WebSockets (over WSS) use TLS encryption to secure data transmission, making it difficult for hackers to intercept the data while being transmitted.
• Browser Compatibility: The protocol is supported by mostly modern web browsers and is compatible with web browsers, mobile (Android/IOS), and desktop platforms.

WebSocket vs. HTTP

HTTP and WebSocket are two different communication protocols used in web applications, each suited for different use cases.

Latency

• When it comes to latency, WebSocket generally has the edge. Since the connection is always open, data can be sent and received instantly, with no need to wait for a new connection to be established. 
• HTTP, on the other hand, establishes new connections for every new request made by the client, which makes it slower compared to WebSocket. As data is sent and received in discrete requests, there’s still much latency.

Resource Management

• HTTP is most efficient in terms of resource management. By multiplexing multiple requests over a single connection and compressing headers it significantly reduces the overhead of establishing new connections. HTTP can handle this efficiently with minimal server resources.
• WebSockets can be resource-intensive. Since WebSockets maintain a constant connection, they require continuous resources to keep the connection open for each user.

When to Use WebSockets

WebSockets are ideal for applications that provide real-time, bidirectional communication. Here are use cases where WebSockets are commonly used.

• Chat Applications: Messaging apps like Slack or WhatsApp depend on WebSockets for instantaneous message delivery.
• Live Sports Scoreboard: WebSockets are perfect for live score updates in sports applications. Since the connection remains open, data can be used in real-time.
• Gaming: Real-time multiplayer games require instant interactions between players. WebSockets provide low-latency communication, allowing players to interact with each other.

When to Use HTTP

HTTP is mostly used in use cases where you need better performance and less latency in handling multiple requests.

• API Service: For APIs that handle multiple requests, HTTP/2’s multiplexing feature allows for the efficient transmission of many requests over a single connection.
• Serving public websites: For websites that primarily serve static, non-static information like news articles, through HTTP is still the preferred option for enhanced security.
• Internal communication: In specific internal systems or development environments where security is less of a concern, HTTP is used.

WebSocket vs HTTP: Comparison Table

Comparison Table WebSocket vs HTTP 

In the end, it all depends on what you are looking for and your use case. If you use speed and a long connection, your perfect choice is the WebSockets protocol. If you want to reduce your resource usage, you go for the HTTP protocol.