From West London Hackspace Wiki
There are a number of development platforms available
- Expressif SDK - the chip manufacturer's full SDK for commercial use but not for the novice or amateur. There are two versions, one based on RTOS and the other based on callbacks.
- ESP-open-SDK - a (Linux-only) toolchain based on the GCC compiler with Xtensa HAL and ESP API SDK.
- Lua - until spring 2015 this was the hacker's choice, but the Lua language is hideous, the bastard child of C, perl, BASIC and perhaps ADA or PL/1.
- Arduino IDE with external board support - by far the easiest, most Arduino libraries either run as they are or have been modified to support ESP8266.