RTOS reliant?

[klaatu2]

I'm new to the ESP32. Is it wholly dependent on RTOS?
I have never needed an OS with previous developments and I'm resistant to using one, but it seems that Espressif has created this ecosystem with RTOS at the core.

Am I understanding this correctly?

[ESP_Sprite]

More-or-less, yes. Specifically the WiFi and Bluetooth stack are fairly complex beasts that need a RTOS to work, and since most projects that use an ESP32 use (one of) those, most SDKs for ESP32 chips contain some sort of RTOS. Theoretically, if you don't use the radio you could go RTOS-less, but given that all drivers and supporting code assume the existence of a RTOS, you'd have to build that almost entirely from scratch.

[mbratch]

ESP-IDF uses FreeRTOS, but if your application is fairly simple, although the RTOS will be there, you don't really have to interact with it in any obvious way. It would just be a single task and the ESP-IDF environment defines a default main task where your code lives. On the other hand, FreeRTOS is fairly light weight and if you need a software timer, or need to have multiple tasks running (virtually) in parallel, then it has facilities for allowing you to do that so you can focus on your application.