The format field in log setup page is like the format in printf but uses the following specifiers:

Specifier	output
%a	auxiliary temperature
%b	Beer temperature
%B	Beer setting
%E	Environment/Room Humidity
%f	fridge temperature
%F	fridge setting
%r	room temperature
%g	gravity
%H	Hostname
%h	Chamber humidity
%m	Mode in integer: 0:Off ,1: FridgeConst, 2:BeerConst, 3:BeerProfile
%M	Mode in character: o, b, f, p
%p	Plato
%P	Pressure reading in PSI
%s	State in Integer. 0:IDLE, 1:STATE_OFF,2: DOOR_OPEN, 3:HEATING, 4: COOLING, 5: WAITING_TO_COOL, 6:WAITING_TO_HEAT, 7:WAITING_FOR_PEAK_DETECT, 8:COOLING_MIN_TIME, 9:HEATING_MIN_TIME
%t	tilt value from iSpindel
%u	UNIX timestamp of last gravity update
%U	‘C’ for Celsius or ‘F’ for Fahrenheit
%v	external device voltage

For example, let beer setting be 20.0 and beer temperature be 18.3, if the format is api_key=TheRealApiKeyHere&field1=%B&field2=%b, the data will be api_key=TheRealApiKeyHere&field1=20.0&field2=18.3.

If the method is GET, the data will append to the url with additional ?, so the result will be http://api.thingspeak.com/update?api_key=TheRealApiKeyHere&field1=20.0&field2=18.3. (GET is usually not recommended.) The Data Type field is used as “Content-Type” in HTTP protocol. When it is left blank, the default value of application/x-www-form-urlencoded will be used. The default type is good for content like A=V1&B=V2.

Due to the memory limitation, HTTPS is not supported on ESP8266. Therefore, if you want to send data to a service that supports only HTTPS, an additional proxy is needed.

You can use Generic HTTP format for thingspeak.com and Brewfather to get exact the same result, but you should use ubidots.com specific settings to setup ubidots.com. It is because that ubidots.com will reject all values if one of them are “null”