# Developer Guide
The Developer Guide is designed to provide developers with the information to get started with EMQX and build applications on top of it.
This chapter explores the core concepts of MQTT, MQTT-specific features, and some extended features in EMQX. We will also explain how to configure these features in EMQX Dashboard and test them using client tools. The following features are covered in the guide:
- MQTT Core Concepts
- Test with MQTT Clients
- Shared Subscription
- Retained Message
- Will Message
- Wildcard Subscription
- Exclusive Subscription
- Delayed Publish
- Auto Subscribe
EMQX's support of the MQTT protocol makes it compatible with most MQTT client libraries and SDKs. This guide also provides step-by-step instructions and code samples to help developers quickly start building their MQTT projects. For a complete list of MQTT client SDKs and their comparison, see MQTT client SDKs (opens new window).
Not all SDKs are displayed on the document.
EMQX also provides API documents to facilitate your development. REST API guides you on quickly getting started with the HTTP management API exposed by EMQX.