MQTT vs WebSocket

When one first looks at MQTT and WebSocket, this looks the same. As in both cases, once the connection is established, then the user can send anything between the client and the server. Also, both are full duplexes which means that both client and the server are speaking and listening at real time. MQTT is message based while WebSocket is session based. Although they are quite similar in some contexts, one can differ from them in certain categories.

What is MQTT?

MQTT stands for Message Queuing Telemetry Transport, a lightweight messaging protocol. It is used for communicating with remote devices where network bandwidth is costs high. For example- Facebook uses MQTT in their mobile versions.

Advantages:

• Efficient data transmission and quick to implement because it is lightweight.
• Use a small amount of power.
• Low network usage.
• The distribution of data is very efficient.

Disadvantages:

• Slower transmit cycles.
• It is unencrypted
• Security issues

What is WebSocket?

It is a real-time protocol that provides a persistent, full-duplex communication channel between a web client and a web server over a single TCP connection. Basically, it creates a two-way channel between a web browser & a server. For Example-  financial tickers, real-time multiplayer games, etc.

minimalAdvantages:

• Allows two-way communication.
• Compatibility between platforms 
• Allows to send and receive data much faster than HTTP.

Disadvantages:

• Do not provide edge caching.
• Non-availability of AJAX-like success mechanisms.
• Web browsers must be fully HTML5 compliant.

Difference between MQTT and WebSocket:

	MQTT	WebSocket
1.	There is a feature available for setting the priority.	There is no feature available for setting the priority.
2.	It is used in client and server applications.	It is used for web client applications.
3.	There is minimum overhead during communication.	It incurs a lot of overhead while using many IOT devices while communicating.
4.	It is designed for IOT devices.	It is designed for a full-duplex/bidirectional communication channel.
5.	In MQTT, multiple parties can subscribe and publish messages.	In WebSocket, point-to-point communication between the client and server is done.
6.	The message distribution is one-to-many.	The message distribution is one-to-one.
7.	MQTT is message-based.	WebSockets are session-based.

Conclusion: MQTT is preferred as it offers features and abstractions that a simple WebSocket does not. Also, MQTT is more suitable than WebSocket in the case of embedded systems as it provides quality service, minimum overhead during communication, and pub/sub-system at the protocol level.