ESP8266 Thing Hookup Guide
Programming the Thing
The ESP8266 has a built-in serial bootloader, which allows for easy programming and re-programming. You don't need a specialized, expensive programmer -- just a simple, USB-to-Serial converter.
We use a 3.3V FTDI Basic to program the Thing, but other serial converters with 3.3V I/O levels should work (e.g. FTDI SmartBasic, FTDI Cable 5V VCC-3.3V I/O, FT231X Breakout). The converter does need a DTR line in addition to the RX and TX pins.
The FTDI Basic's 6-pin header matches up exactly to the Thing's 6-pin serial port header. To set up for programming, simply connect the FTDI directly to this port -- take care to match up the DTR and GND pins!
If you solder female headers to the Thing, plugging a 6-pin row of right-angle male headers between the FTDI and header helps create a temporary programming interface.