I use Fastify because , its better and faster than express and few other popular node.js frameworks. its has an awesome concept of decorators.
MQTT is one of the light weigh, its small size, low power usage, minimized data packets and ease of implementation make the protocol ideal of the “machine-to-machine” or “Internet of Things” world. we have used it to communicate with devices from server.
I have used PubNub for a cab booking application, to stream drivers and users location.
I use Hugo because ,building static is really easy with using Hugo.
Node.js i have use for backend (server side) development most of the time.
I use MongoDB because , its on of the best nosql DB, it accepts high write throughputs.
I use Redis because , its really easy to use, for caching and scheduling i use it with Bull.js.
I use DigitalOcean because it's cheap, i use it basically to deploy stuffs.