Choose the firmware that interests you
ESP Easy Mega is the new version of an ESP8266 firmware module that allows you to create connected objects without any programming. ESPEasyMega can be installed using the flasher or by compiling the source code using PlatformIO. ESP Easy has a mini web server that allows you to configure the module remotely. Many sensors are supported (Dallas DS18B20, DHT11, DHT22, Si7021, TCR5000, BMP085, BMP180, BMP280, BME280, BH1750 (GY-302), TSL2561, Wiegand, PN532, HC-SR04, IR, ADS1115, PCF8591 , INA219 …) as well as actuators (relay, led, servo, PWM …). ESP Easy also includes a script editor (called Rules) which allows you to create small scenarios. You can transform an ESP8266 into a fully independent mini home automation server. Even if you have no programming knowledge, you can develop your own connected objects (temperature sensors, weather station, air quality, CO2 …) and connect them to a DIY home automation server such as Domoticz, Home Assistant, OpenHAB…
ESP Easy (R120) or ESP Easy Mega, which one to choose?
There are 2 branches (versions) of the firmware which can cause some confusion when starting out.
ESP Easy is the stable version (R120) that you can get here. Follow this tutorial which explains step by step how to install and configure the ESPEasy R120 firmware on an ESP8266 module. In the event of a problem, use the ESP Tools utility from Espressif. Everything is explained step by step in this tutorial.
ESP Easy Mega is the version under development available here. It embeds a larger number of plugins, a new interface and supports (some) ESP32 development boards. To find out more, you can read this overview article. Attention, to work your ESP8266 card must have at least 1MB of flash memory (be careful to choose your ESP-01 module)