Websocket vs. MQTT vs. CoAP: Which is the Best Protocol?

Choosing the most appropriate IoT protocol for your project can be difficult. There’s so much choice out there, and each of them has its own strengths and weaknesses. 

We’re here to help you choose the right IoT protocol for your stack by analyzing three of the biggest protocols available to developers: 

• Websocket
• MQTT
• CoAP

We’ll make a comparison of Websocket and MQTT, look at the differences between CoAP and MQTT, and then suggest some other alternatives. So, Websocket vs. MQTT? CoAP vs. MQTT? Which will come out on top?

For a more thorough deep dive, check out our Comparison of IoT Protocols for Developers.

The Main Differences Between MQTT vs. Websocket

We want to start off by explaining the differences between Websocket vs. MQTT. They are both IoT protocols in categorization, but that’s where the similarities stop.

MQTT (Message Queue Telemetry Transmission) uses the publish/subscribe network protocol, which is used to transport messages between devices directly in the web browser. It’s extremely lightweight and is, therefore, most suitable for smaller, constrained devices. Otherwise, you could have issues with latency.

On the other hand, Websocket is a computer communication protocol. It creates a two-way channel between a web browser and a server. Furthermore, it runs over a single TCP connection. Websocket is much more heavyweight than MQTT, but still less so than HTTP. But while it may have higher overheads, it doesn’t suffer from latency issues.

MQTT vs. Websocket: Which One is Better Suited as an IoT Protocol?

From an IoT perspective, MQTT is arguably the better option of the two.

This is because Websocket isn’t extremely well suited to IoT devices. It was initially designed for the full-duplex communication channel between browsers and servers. So, while it can be used for connected embedded devices, it will not be able to hold signals as well. 

On the other hand, MQTT was specifically designed for IoT devices. Despite its latency issues and certain problems it can present to developers, it is good at minimizing bandwidth and ensuring message delivery (via Quality of Service).

MQTT and Websocket Comparison Table

Here’s a comparison between the two protocols, at a glance:

CoAP vs. MQTT: What Are the Main Differences and Similarities?

While we’ve established that MQTT is generally considered to be a better option for your IoT stack than Websocket, we now need to see how it compares alongside CoAP (Constrained Application Protocol). Here’s how the key specifications differ.

While some of the technical specs differ, the two protocols also share plenty of similarities:

• They’re both open IoT standards
• They’re both better suited to constrained environments than HTTP
• They provide mechanisms for asynchronous communication
• They both run on IP
• And they both have a range of implementations

CoAP vs. MQTT: Which One is Better Suited as an IoT Protocol?

This really depends on what you’re after. There are pros and cons of MQTT and pros and cons of CoAP.

MQTT is well-suited if you’re looking for a protocol that’s lightweight and battery friendly. However, steer clear if you’re concerned about latency issues or you’re looking for an IoT protocol that’s developer friendly and supports real-time interaction.

CoAP is a good option if you’d like RESTful programming, but HTTP+TLS/SSL is too big of a protocol for your device. You can solve this by using CoAP with DTLS. That being said, if you’re looking for lower overheads and extreme message reliability, you should opt for a different protocol.

CoAP+Nabto: An even Better Solution?

As discussed, CoAP is an extremely versatile IoT protocol. However, if one of the devices is placed behind a firewall, communication between the devices breaks down. That is where Nabto can provide a solution. 

A typical IoT use case is that you want to control your device using a smartphone, which, of course, is a simple use case to solve if both smartphone and IoT device are located on your home network. But, once the user moves away from their home network, it is quite hard to establish a connection between the smartphone and the IoT device. 

The reason is your home network is (hopefully) protected by a firewall, which doesn’t allow connections from the outside world (internet wise) to the devices connected on your local internet network (protecting you against all kinds of hackers). This is what Nabto adds to the equation: an easy way for establishing a connection from smartphone to IoT device while still maintaining a high security level on your home network. 

This is done while ensuring (via strong authentication) only entities (smartphone apps) that the user explicitly has allowed to connect, can connect. And, when data is transmitted, it is protected by strong encryption.

With a few lines of code, Nabto Edge can be installed on top of CoAP. This allows your IoT stack to easily, securely and remotely communicate through firewalls, thus increasing message reliability (which is usually a limitation of CoAP as an IoT protocol). So, you get all the benefits from CoAP, including a simple way to remotely connect to the IoT device (from the smartphone).

Read more information on the benefits of a CoAp and Nabto integration and how it works

The Bottom Line

So, between Websocket vs. MQTT vs. CoAP, which IoT protocol is the best for your project ? Well, WebSocket is best avoided. It doesn’t hold signals well and is ill-suited to the world of IoT. 

That leaves MQTT and CoAP. While MQTT is lightweight and battery friendly, it has issues with latency. On the other hand, CoAP is usually held back by its message reliability. 

However, when used with Nabto Edge, this previously limiting factor is eradicated. Coupled with the remote access and the RESTful programming capabilities of CoAP, Nabto paired with CoAP could provide the most robust solution for your project. 

If you want to learn more about Nabto Edge – or any of our other IoT solutions – get in touch with us today.

Read Our Other Resources

We’ve published a range of IoT resources for our community, including:

• A Comparison of IoT Protocols for Developers, which provides a complete comparison of the major protocols and standards available.
• Buying versus building an IoT platform, which discusses how to choose the best option for you.
• Our guide on how to Develop IoT Apps and what platforms you can use.
• What is MQTT in IoT and Should You Use It?, which provides an overview of MQTT in IoT.