A convenient programming app
Developed by Anton Smirnov, ArduinoDroid - Arduino/ESP8266, or ArduinoDroid, is a freemium, third-party-developed programming tool for viewing sketch samples and writing and editing Arduino, ESP8266, and ESP32 sketches on your device. Before downloading this app, make sure that your phone has 500 MB of free space in your internal storage.
No need to root your device
ArduinoDroid - Arduino/ESP8266 doesn’t need an internet connection, making it ideal for on-the-go Arduino programmers. It supports no-root sketch compilation and supports sketch uploads via USB or Wi-Fi connection. Being a freemium app, there are a couple of features exclusive to paid users.
Some of these features include an in-app tiny keyboard, file navigator, themes, and many more. You can purchase all features in one “Premium” package, or just buy them as a standalone product. Unfortunately, due to Android’s security policy, you can’t install this program on an SD card.
For on-the-go programmer
Overall, ArduinoDroid - Arduino/ESP8266 is the epitome of convenience. Here, you can open, edit, compile, and upload sketches from the comfort of your device. It doesn’t require a rooted device, too. However, as mentioned, be sure your internal storage has ample space before installing the app.