Mosca vs Mosquitto: What are the differences?

What is Mosca? A Node.js MQTT broker. A Node.js MQTT broker, which can be used as a Standalone Service or embedded in another Node.js application.

What is Mosquitto? An open source message broker that implements the MQTT protocol. It is lightweight and is suitable for use on all devices from low power single board computers to full servers.. The MQTT protocol provides a lightweight method of carrying out messaging using a publish/subscribe model. This makes it suitable for Internet of Things messaging such as with low power sensors or mobile devices such as phones, embedded computers or microcontrollers.

Mosca and Mosquitto can be primarily classified as "Message Queue" tools.

Mosca is an open source tool with 2.84K GitHub stars and 501 GitHub forks. Here's a link to Mosca's open source repository on GitHub.