Tricks

Defining virtual pins as constants

Blynk Agent on Heroku with Node.js

NodeRED + dashboard

Auto-reconnect network

Slider widget - floating point value?

Sketches with multiple .cpp files

Write multiple Virtual Pins in a loop

for (int pin=V1; pin < V4; pin++) {
   Blynk.virtualWrite(pin, LOW);
   delay(5);
}