Simple WebServer library for AVR, Teensy, SAM DUE, SAMD21, SAMD51, STM32F/L/H/G/WB/MP1, nRF52 boards running ESP8266/ESP32 AT-command shields with functions similar to those of ESP8266/ESP32 WebServer libraries. The library supports HTTP GET and POST requests, provides argument parsing, handles one client at a time.