How to set up CocoaMQTT with SSL in Swift?

For one-way SSL, set allowUntrustCACertificate to true; for two-way, generate a .p12 file using OpenSSL commands from the README and configure it in the client. Examples include code for both scenarios with delegate handling.

Does CocoaMQTT fully support MQTT 5.0 features?

Yes, it supports key MQTT 5.0 features like connect properties, topic aliases, and session expiry, as shown in the CocoaMQTT5 usage with MqttConnectProperties. However, advanced features like shared subscriptions may require verification.

CocoaMQTT vs Moscapsule for iOS MQTT?

CocoaMQTT offers native MQTT 5.0 and WebSocket support with active maintenance from EMQ, while Moscapsule is older and may lack recent updates. CocoaMQTT is better for modern Swift projects needing full protocol compliance.

How to use WebSocket with CocoaMQTT?

Import CocoaMQTTWebSocket and Starscream, create a CocoaMQTTWebSocket instance with a URI, and pass it to the CocoaMQTT initializer. The README provides code for adding custom headers and enabling SSL for WSS connections.

Is CocoaMQTT compatible with SwiftUI?

Yes, it can be used in SwiftUI by importing the library and managing state in views or view models, but it requires handling delegate callbacks or closures for asynchronous message handling, as demonstrated in the example app.

How to handle reconnection in CocoaMQTT?

Implement custom logic in the delegate methods like mqttDidDisconnect, where you can check errors and call connect() again. The library doesn't provide built-in automatic reconnection, so developers need to manage this manually.

CocoaMQTT — Native Swift MQTT Library

What is CocoaMQTT?

CocoaMQTT is an MQTT client library written in Swift for iOS, macOS, and tvOS applications. It enables devices and apps to publish and subscribe to messages using the lightweight MQTT protocol, which is commonly used in IoT, real-time messaging, and mobile connectivity scenarios. The library supports both MQTT 5.0 and 3.1.1 specifications, providing a native solution for Apple ecosystem developers.

Target Audience

iOS, macOS, and tvOS developers building applications that require lightweight messaging, IoT device communication, or real-time data sync with MQTT brokers.

Value Proposition

Developers choose CocoaMQTT for its native Swift implementation, support for the latest MQTT 5.0 features, and seamless integration with Apple's platforms, including SSL security and WebSocket transport options.

MQTT 5.0 client library for iOS and macOS written in Swift

Use Cases

Best For

Building iOS apps that connect to IoT devices or sensors
Implementing real-time messaging features in macOS applications
Creating tvOS apps for smart home dashboards or controls
Developing cross-platform Apple apps that use MQTT for data sync
Adding secure, bidirectional communication to mobile projects
Connecting to MQTT brokers over WebSocket in Swift projects

Not Ideal For

Projects targeting non-Apple platforms like Android, web, or watchOS
Applications with strict dependency minimization to reduce bundle size or avoid third-party risks
Teams preferring reactive programming patterns like Combine or RxSwift without additional wrapper layers
Environments requiring out-of-the-box server-side rendering or non-Swift language integration

Pros & Cons

Pros

Dual Protocol Support

Supports both MQTT 5.0 and 3.1.1 specifications, with separate CocoaMQTT5 and CocoaMQTT classes in the usage examples, ensuring compatibility with modern and legacy brokers.

Secure SSL/TLS Options

Provides one-way and two-way certificate authentication, including code snippets for allowing untrusted CA certificates and generating .p12 files with OpenSSL.

WebSocket Transport

Enables MQTT over WebSocket and WSS with the CocoaMQTTWebSocket class and Starscream dependency, allowing custom headers and secure connections as shown in the setup steps.

Modern Swift API

Written in Swift 5 with support for delegate patterns and closure-based callbacks, making it idiomatic and easy to integrate into Apple platform codebases.

Cons

Dependency on External Libraries

Relies on third-party sockets like MqttCocoaAsyncSocket and Starscream for WebSocket, which can introduce version conflicts, maintenance overhead, and increased project complexity.

Complex SSL Configuration

Two-way SSL requires manual generation of .p12 files with specific OpenSSL versions (e.g., 1.1), adding error-prone setup steps not needed in simpler clients.

Limited Platform Support

Only compatible with iOS, macOS, and tvOS, excluding watchOS and non-Apple platforms, which restricts its use in cross-platform or hybrid app scenarios.

WebSocket Overhead

Enabling WebSocket support necessitates additional imports and configurations, such as importing CocoaMQTTWebSocket and Starscream, unlike streamlined TCP-based MQTT setups.

What is CocoaMQTT?

Target Audience

iOS, macOS, and tvOS developers building applications that require lightweight messaging, IoT device communication, or real-time data sync with MQTT brokers.

Value Proposition

Use Cases

Best For

Building iOS apps that connect to IoT devices or sensors
Implementing real-time messaging features in macOS applications
Creating tvOS apps for smart home dashboards or controls
Developing cross-platform Apple apps that use MQTT for data sync
Adding secure, bidirectional communication to mobile projects
Connecting to MQTT brokers over WebSocket in Swift projects

Not Ideal For

Projects targeting non-Apple platforms like Android, web, or watchOS
Applications with strict dependency minimization to reduce bundle size or avoid third-party risks
Teams preferring reactive programming patterns like Combine or RxSwift without additional wrapper layers
Environments requiring out-of-the-box server-side rendering or non-Swift language integration

Pros & Cons

Pros

Dual Protocol Support

Supports both MQTT 5.0 and 3.1.1 specifications, with separate CocoaMQTT5 and CocoaMQTT classes in the usage examples, ensuring compatibility with modern and legacy brokers.

Secure SSL/TLS Options

Provides one-way and two-way certificate authentication, including code snippets for allowing untrusted CA certificates and generating .p12 files with OpenSSL.

WebSocket Transport

Enables MQTT over WebSocket and WSS with the CocoaMQTTWebSocket class and Starscream dependency, allowing custom headers and secure connections as shown in the setup steps.

Modern Swift API

Written in Swift 5 with support for delegate patterns and closure-based callbacks, making it idiomatic and easy to integrate into Apple platform codebases.

Cons

Dependency on External Libraries

Relies on third-party sockets like MqttCocoaAsyncSocket and Starscream for WebSocket, which can introduce version conflicts, maintenance overhead, and increased project complexity.

Complex SSL Configuration

Two-way SSL requires manual generation of .p12 files with specific OpenSSL versions (e.g., 1.1), adding error-prone setup steps not needed in simpler clients.

Limited Platform Support

Only compatible with iOS, macOS, and tvOS, excluding watchOS and non-Apple platforms, which restricts its use in cross-platform or hybrid app scenarios.

WebSocket Overhead

Enabling WebSocket support necessitates additional imports and configurations, such as importing CocoaMQTTWebSocket and Starscream, unlike streamlined TCP-based MQTT setups.

CocoaMQTT

What is CocoaMQTT?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

CocoaMQTT

What is CocoaMQTT?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?