I have read a few threads here and elsewhere on how to do this. This is what I have come up with so far: 1. Define the environment variable in my shell start-up. I can confirm this is working by doing: # echo $SECRET too secret to be in the repo # 2. Create a build-flag in platformio.ini: ... build_...

This works really well and is extremely fast. Thank you again.

Thank you, I will try this.

I am new to ESP32s. I have an application that generates two interrupts on separate GPIO lines. Accessing timestamps for real time seems to be an integer. Would using this in conjunction with a CPU clock tick count be the most accurate way of measuring the interval? Or is there a better way?