A custom ESP32 embedded solution with modular firmware, security features and Wi-Fi/BLE connectivity for connected products. This DEV.to version is a short engineering note extracted from the case study, with the complete English page linked at the end. Stack at a glance ESP32, ESP-IDF, C, FreeRTOS, Wi-Fi, Bluetooth Low Energy, NVS, Secure Boot. Why this matters Many ESP32 prototypes work in the lab but become fragile when they need provisioning, updates, configuration storage and diagnostics. A product-oriented firmware base makes the device easier to maintain across hardware variants and field updates. Architecture notes Split boot, application logic, configuration and communication concerns instead of building one monolithic firmware loop. Use ESP-IDF components deliberately: NVS for persistent configuration, FreeRTOS tasks for concurrency and clear interfaces for Wi-Fi/BLE behavior. Design provisioning, fallback and update strategy before the device reaches production testing.…