With free FLX app for Android you can create scripts and applications, even with UI screens, that use various APIs (e.g. HTTP, File, JSON, IFTTT, Sensors, Android APIs, and BeanShell) to carry out defined functions or tasks. Applications and UIs are defined with easy-to-use but powerful visual programming language that have similar functions to Kotlin.

App's home page: https://floxp.app
Google Play Store: https://play.google.com/store/apps/details?id=com.flx

Under to hood, FLX is based on a Lisp variant, which I have just open sourced: https://github.com/Fuusio/flx-lisp

 

FLX v1.2.2 will have support for creating fully customisable MQTT clients with custom UIs for Android. And without developing the client app using Android Studio - just by using the FLX app : https://floxp.app/2021/02/22/flx-and-mqtt/

 

FLX v1.2.3 is now available (https://play.google.com/store/apps/details?id=com.flx) and provides an API for implementing fully customisable MQTT clients. The app provides a project template for creating a simple client. v1.2.4 will provide a project template with UI for FLX applets that implement a generic MQTT client. Users can then modify this template based applet.

You can use this public web socket based front end for the HiveMQ broker for testing your MQTT applet: http://www.hivemq.com/demos/websocket-client/