OTP SMS SERVICE
Budget: $250 – $750 USD
You will have complete ownership of your OTP system, from hardware to system software. The hardware components include ESP32 and SIM Module, while the server is powered by a self-built Blynk system on your VPS, with several PHP scripts used for data processing.
Demo: http://demo.hackanidea.net/otp/
Demo: http://demo.hackanidea.net/otp/