Sonoff Basic R3 and Blynk

I would like to find out if there is anybody that can help to get the Sonoff BasicR3 to work with Blynk. Possible to load my own sketch on the Sonoff BasicR3?

I’ve never flashed any of the Sonoffs that have DIY mode, I’ve always used the ones that need an FTDI connecting to them to flash new firmware.
Looking at the instructions for DIY mode it looks quite simple, but you’ll need to ensure that you add OTA capability to your sketch so that you can continue to have a way of adding wireless updates for bugfixing in future.
Note that the latest versions of the Arduino core enquire the OTA service to be initialised AFTER the connection to your WiFi (if you’re using Blynk.begin then this means after you call Blynk.begin in your void setup).

Personally, I’d test the code on a NodeMCU or similar, then create a .BIN file for the Generic ESP8266 and upload it via the Sonoff flasher.