MQTTnet review
A flexible MQTT client and broker library for developers embedding MQTT in .NET apps.
Reviewed by iTechGuides Editors · Editorial team · Updated Nov 2026
MQTTnet is an open-source .NET library that provides both an MQTT client and a server (broker). It is aimed at developers who want to embed MQTT communication in their own applications rather than subscribe to a hosted broker. The project is delivered through NuGet and can be used with ASP.NET Core, making it a fit for teams building .NET services that need client and broker functionality together.
The broker supports MQTT protocol versions 4 and 5, with TCP, TCP with TLS, and WebSocket communication channels. On the server side, developers can validate client credentials, intercept messages to transform or extend them, and validate subscriptions to deny access to selected topics. It also exposes a list of connected clients. Retained messages are supported, while persistence for them is provided through custom interface methods. These capabilities make MQTTnet more configurable than a basic client library, but they put implementation choices in the application's hands.
MQTTnet is self-hosted, so it suits developers who want control over how a broker is embedded and operated, not buyers seeking a turnkey managed service. Its open-source model avoids a paid plan decision, while documentation and community are the listed support channels. Teams should weigh the work of hosting and operating it against that control. MQTTnet is a reasonable fit for .NET projects that need broker behavior inside an application; organizations looking for a managed service or an explicitly documented clustering option should consider a dedicated broker product instead.
MQTTnet pros and cons
- Where it wins
- Includes both MQTT client and broker capabilities in one library
- Supports MQTT versions 4 and 5 over TCP, TLS, and WebSockets
- Offers credential validation, message interception, and topic checks
- Where it doesn't
- Requires developers to host and operate the broker themselves
- Retained-message persistence depends on custom interface methods
- Not positioned as a managed broker service
MQTTnet fact sheet, pricing and score →
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