Chat & Messaging Protocols: What Are They & How to Choose the Best One

Yet how these messages are exchanged is a bit more complex than hitting the send button. Relaying messages from one part of the world to another is possible in part thanks to chat and messaging protocols. 

If you are looking to develop a new messaging application, there are many types of messaging protocols your team can choose from to power your chat communications. However, there are a few protocols that are commonly and successfully used in the messaging industry. Understanding how these protocols work will help you decide which to use and how to build your chat application.

Understanding Messaging Protocols

Messaging protocols are the set of rules that govern communication and data exchange on the internet. They are a key part of networking technologies that enable the Internet of Things (IoT) to communicate between devices, applications, or the cloud. The protocol that underpins internet communication is called TCP/IP or Internet Protocol.

IP is the most basic level of messaging protocol and is made up of two types of traffic: User Datagram Protocol (UDP) and Transmission Control Protocol (TCP). UDP is a fast and efficient transmission for single directions. TCP is bi-directional and thus takes a bit longer. However, it is also more reliable since there's confirmation that a message was received.   

Chat messaging applications require an instant messaging protocol that allows for real-time communication between users. Both sender and receiver of a chat must follow the same data transfer protocol for it to be successful. Depending on the benefits and features of your chat application, additional chat protocols can be built on top of either UDP or TCP. 

10 Common Messaging Protocols 

Developers use many different kinds of messaging protocols that support IoT applications. Knowledge of the technology behind chat apps is crucial to the success of your messaging solution. It helps you understand what's possible in the market, weigh your options, and decide which protocol is best for your goals.

Below we'll take a look at some of the most common messaging protocols to consider using in your chat application. 

1. MQTT (Message Queuing Telemetry Transport) 

The MQTT, or Message Queuing Telemetry Transport, protocol is popular due to its extremely lightweight publish/subscribe messaging transport. It runs on the layer of the network and transfers data between machines bi-directionally. The MQTT protocol has a small code footprint and is ideal for situations in which devices might have limited bandwidth or other constraints. 

Pros 

• Best for low-power applications 
• Ideal for battery-powered mobile devices 
• High reliability in delivering messages 
• Minimal CPU resources
• Flexible quality of service (QoS) options
• OASIS standard protocol

Cons  

• Generally not suitable for consumer software apps 
• Lack of encryption
• Minimal security support (can reduce risk by working with security providers)
• Relatively low speed 
• No video call capabilities

Use case examples: A variety of industries, such as manufacturing, telecommunications, automotive, oil, and gas, that tend to use automation. MQTT helps them aggregate additional manufacturing data without adding too much network demand. 

2. AMQP (Advanced Message Queuing Protocol)

Like MQTT, AMQP (Advanced Message Queuing Protocol) is an open standard application layer protocol that runs on top of the TCP layer. AMQP's corporate history caused it to become an optimal protocol for sophisticated applications. Its binary protocol supports a wide variety of messaging apps and communication patterns. Unlike MQTT, it is not specifically built for IoT solutions. However, its focus on instant messaging delivery reliability works well for IoT scenarios.

Pros 

• Binary application layer protocol 
• Point-to-Point and publish/subscribe messaging uses 
• Supports end-to-end encryption
• Secured connections with SSL 
• Backs QoS for message delivery 
• Uses simple peer-to-peer delivery 
• Broad compatibility with various message scenarios

Cons  

• High bandwidth requirements compared to other protocols 
• Not backward compatible with prior versions of the protocol
• Uses large amounts of power and memory 

Use case examples: Business communications such as financial use cases at an enterprise instant messaging system due to its secure, fast connection. 

3. DDS (Data Distribution Service)

The DDS (Data Distribution Service) protocol is used with real-time systems and acts as a bridge between machines. Unlike some protocols, this protocol is brokerless (meaning it is M2M: machine to machine). DDS uses low computing data and is highly reliable and efficient due to its extensible architecture. As a middleware software, DDS handles the tricky job of managing communication paths so that developers can focus on building apps.

Pros 

• Scalable, dependable high performance  
• Built for real-time systems 
• Low overhead 
• Uses publish/subscribe messaging pattern 
• Direct connection between devices 
• Developed from low-footprint devices to the cloud 
• High-quality QoS to apps 

Cons  

• Heavyweight protocol 
• Difficult to use in embedded systems 
• Consumes more bandwidth than some protocols (like MQTT) 
• Cannot interface with webpages 

Use case examples: High-stress application scenarios such as hospitals and healthcare, military defense, or air-traffic control benefit from its real-time transfer and efficient architecture. 

4. XMPP (Extensible Messaging and Presence Protocol)

XMPP, or Extensible Messaging and Presence Protocol, was originally known as Jabber and was created for instant messaging (IM) through TCP link. Its scalability applies to long-distance messaging. This protocol is based on XML (Extensible Markup Language) and enables near real-time exchanges of XML data between two or more devices. Today, this instant messaging protocol can be used when building a chat application, a VoIP (Voice over IP), gaming, or other IoT systems. 

Pros 

• Supports voice calls, video calls, and file transfer
• Extendible design 
• Open-source flexibility  
• Uses standard internet communication protocol (ICP)
• Communicates through HTTP 
• Stability and reliability 
• Decentralized architecture
• Can isolate on a private network for added security 

Cons  

• Lacks QoS support 
• Not effective in sending binary data 
• No end-to-end encryption
• Relatively slow 

Use case examples: With reliable real-time exchanges and scalability, this best suits consumer software like smartphone access to a smart thermostat or a gaming console with instant messaging between gamers. 

5. CoAP (Constrained Application Protocol)

The CoAP, or Constrained Application Protocol, is specialized for constrained devices. In other words, it requires low power and works across lossy networks. It is used for IoT devices as well as other systems like Short Messaging/Message Service (SMS) on mobile networks. CoAP is lightweight and runs on UDP, a connectionless, one-directional protocol. It follows a similar request/response protocol as HTTP, in which every request generates a response. 

Pros 

• Low power usage
• Used on constrained devices
• Uses Distributed Ledger Technology (DLT) Security
• Small packet sizes 
• Quick communication with devices 

Cons  

• There is no broadcasting option 
• Lacks some reliability 

Use case examples: Best suited for smart-home devices and smart-city systems with limited computing powers that would not be vulnerable or have detrimental consequences due to cyberattacks.  

6. WebSocket 

WebSocket can serve as the foundation for large-scale instant messaging applications. WebSocket is a two-way communication protocol that relies on a TCP connection. It occurs between "a client running untrusted code in a controlled environment to a remote host that has opted-in to communications from that code." In other words, this protocol provides a way for a user's browser-based application to have two-way communication with a server without relying on multiple HTTP connections.

Pros 

• Real-time chat functionality
• Updates interface with new data automatically 
• Two-way communication is faster than HTTP and AJAX 
• Compatible between web, desktop, and mobile platforms 
• Only has a 2-byte overhead cost 

Cons  

• Reliability limited by a user's internet connection 
• Requires a fully HTML5-compliant web browser 
• Does not provide intermediary/edge caching 
• Cannot employ friendly HTTP statuses and other elements 
• Harder to develop than HTTP 

Use case examples: Social feeds, multiplayer games, and online education benefit from its fast, two-way communication and low overhead cost. 

7. IRC (Internet Relay Chat) 

The IRC, or Internet Relay Chat, protocol allows for real-time text messaging. Since this protocol was originally developed before broadband internet access was widespread, it is not necessarily the best match for today's network capabilities. However, there are some text-based scenarios that it is effective for, like group discussions in chat rooms called "channels" as well as private messages between two people.  

Pros 

• Reliable messaging and support for file sharing 
• Decentralized 
• Flexible and robust 
• Real-time communication
• Access levels allow for better privacy

Cons  

• No video or voice call support
• Declining number of active users 
• Consumes high bandwidth 
• Flooding concerns 
• Can have issues with security and cyberbullying 

Use case examples: Streamers messaging on Twitch, military mission comms, and Linux operating system members use this protocol due to its real-time comms and access to better privacy. 

8. RCS (Rich Communication Services) 

RCS Chat (Rich Communication Services) is a protocol that was designed for mobile phones. Through RCS, contacts do not need to use the same chat application to exchange messages. It also improves upon the default SMS by adding features such as supporting media, read receipts, and calendar integrations. RCS also extends the text character limits to 8,000 and improves image quality. Through RCS, users can integrate their contact apps and share contacts (like in WhatsApp). 

Pros 

• Optimized for mobile phones 
• Extends character limits
• Supports GIFs, videos, payments, and geolocation sharing 
• Allows for IP voice calls 
• Includes delivery and read receipts
• Shows typing indication
• Enables businesses and service messages 

Cons  

• Security issues — does not support end-to-end encryption 
• Unsupported by Apple iOS
• Costs have not been finalized and are difficult to forecast/budget for
• No way to track RCS users 
• Compatibility is limited when reverting to the default SMS 

Use case examples: Since RCS is application agnostic, this protocol is best for actions like personal text messaging, submitting surveys, booking appointments, and making payments. 

9.  SIP/SIMPLE (Session Initiation Protocol) 

SIP, or Session Initiation Protocol, is a leading messaging protocol for phone technologies. SIMPLE is a specific application of SIP, which stands for "Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions." This means it offers features such as presence (when users can detect another user is online), session mode, and non-session/page mode. However, it does not support contact lists or message histories, making it a good option for customer support use rather than social use.

Pros 

• Open standard compatible 
• Relatively flexible 
• Supports text and video messaging 
• Internet Engineering Task Force oversight
• Lower communication costs based on actual use 
• System-wide management with central console
• Scalability and independence from telephone infrastructure
• Integrates into other software 

Cons  

• Not ideal for social media instant messaging 
• Users cannot download it and immediately use it 
• Depends on your internet bandwidth to remain connected 
• Can lose entire system if copper phone lines are down 
• At risk of security or system breaches without proper precaution 

Use case examples: As a protocol specializing in phone technologies, this is best suited for actions like modifying voice calls and video conferencing.   

10. WebRTC (Web Real-Time Communications) 

WebRTC (Web Real-Time Communications) is an open-source protocol that enables voice, text, and video communication between devices and browsers in real time. With WebRTC, software developers use application programming interfaces (APIs) written in JavaScript. Developers can then use these APIs to create peer-to-peer (P2P) connections. As a low-latency protocol with flexible capabilities, developers don't have to worry about compatibility or support for multimedia content. 

Pros

• Flexible due to free, open-source nature  
• Real-time latency 
• Reduces the need for in-house manual integration work 
• Adaptable according to network condition changes (can adjust quality, bandwidth, and traffic flow)
• Compatible with most major web browsers and operating systems
• Third-party components or plugins are not required  

Cons

• Bandwidth issues due to P2P browser connections 
• High maintenance costs 
• Inconsistent media quality
• Limited support for any compatibility issues that might pop up 
• Unclear security and privacy standards 
• Inconsistent QoS 

Use case examples: Messaging apps like WhatsApp and Facebook Messenger use this protocol due to its flexibility and compatibility, as well as real-time latency for instant messaging.  

Choosing the Best Chat and Messaging Protocol for Your Business

The best protocol option for you will address the most important use cases and features you're looking for in a messaging application. Although you likely won't be able to find one that fits every use case and feature you desire, you can evaluate each against the below criteria to help you narrow down your options. 

Privacy & Security 

If you work in an information-sensitive industry, such as fintech or healthcare, you'll need to select messaging protocols with security features like end-to-end encryption (e.g., AMQP). Keep in mind that customers across industries may have varying privacy preferences. Knowing what your target audience prefers can also help you make a decision.  

Compatibility & Scalability 

Compatibility across devices allows more people to use your chat or messaging application on their preferred device. And, if your business is on a high growth trajectory, it's also important to consider scalability. Select a protocol that is compatible with the greatest number of devices and has scalability potential (e.g., XMPP).    

Performance 

The performance of your messaging application can impact the user's experience and, therefore, your business. Make sure the protocol you choose can handle the volume and rate of messages that will be exchanged. You'll also need to consider which protocols have low overhead and what their latency is like. For one-to-one or group messaging cases, real-time latency is the most ideal (e.g., DDS, XMPP, IRC, WebSocket, and WebRTC.)  

Implementation & Reliability

Another important aspect to consider is how difficult it is to implement and manage the protocol. Ideally, it should be easy for your developers to integrate with the rest of your system. From there, it is also optimal if you choose one that is rated as highly reliable (e.g., MQTT, AMQP, DDS, XMPP, and IRC). Make sure that it guarantees delivery and can handle errors automatically to ensure that messages are delivered.  

Cost 

Your budget might be the most impactful on your messaging protocol choice. Compare the costs of each protocol through calculations and predict what the costs may end up being. Consider what other factors will take up some of the budget already, such as building an application in-house or choosing to outsource. 

Frequently Asked Questions 

What protocols are best for chatting? 

The best protocol for your chat application depends on your feature and use case needs. However, the most common ones include WebRTC, WebSocket, IRC, XMPP, MQTT, SIP/SIMPLE, AMQP, RCS, and CoAP.

What protocols are used for secure messaging? 

The protocols that are most secure are CoAP, XMPP, and AMQP.

What are common types of messaging systems? 

Common types of messaging systems include: Short Message Service (SMS), Multimedia Messaging Service (MMS), instant messaging (IM), push notifications, In-app messages, and Rich Communication Services (RCS).

What is MQTT vs. XMPP?

Here are a few points of comparison from TechTarget:

• MQTT is lightweight and better for memory-constrained devices than XMPP. 
• XMPP can define message format and structured data, while MQTT cannot. 
• XMPP creates device identities, while MQTT requires separate broker implementations. 
• XMPP supports communication between devices from different manufacturers and platforms, while MQTT cannot. 
• MQTT has various levels of quality of service (QoS), while XMPP is not as flexible.
• XMPP scales very easily, while MQTT does not. 

What are the most common types of chat? 

The most common types of chat include instant messaging, Internet Relay Chat (IRC), ICQ, voice chatting, and video chatting. 

Getting Started with Messaging Protocols  

Now that you know more about the various messaging protocols, you may already know which one is most suitable for your business. However, if that's not the case, don't fret! Instead of committing to one, you can begin testing out various protocols as you build your chat messaging application.  

Start by listing out the criteria that are most important for you on a shared spreadsheet or project management software with your developers. As your team works through the testing and provides feedback, eliminate the protocols that aren't a good fit. Eventually, you'll find the one for you, and soon you'll be on your way to an excellent chat application for you and your users!