Alvaro Costa developed ES module support for the WebServer component in the espressif/arduino-esp32 repository, enabling ESP32 devices to serve JavaScript ES modules and support modern frontend workflows. He implemented MIME type handling for .mjs files, allowing seamless integration with contemporary web tooling and improving code organization for embedded web applications. Working primarily in C++ and leveraging embedded systems expertise, Alvaro focused on standards compliance and maintainability. Although no bugs were reported or fixed during this period, his work addressed a key gap by unlocking modular frontend development on ESP32, demonstrating depth in both web development and embedded software engineering.