ESP8266 (without Arduino)

HTU21D is with I2C interface to, and remember to pull the lines up.
www.google.dk/search?q=i2c+pullup&tbm=is...B7UasuDrQfZ-bY5wU%3D

Its a link to a picture on how to pull up I2C.
To pullup to 3v3 use 2k2.

And if your HTU21D is on a modul, maby the lines is already pullup. And you can only have one pullup on the string.

Thanks for the reply I take it are use to resistors on each line instead of just connecting the sensor directly to the ESP not quite sure on the resistor values but I found this
Would this be okay.
Also not sure how to call additional sensors to the url.
Thanks for your advice.

Yes it ok, if it NOT at the moduel with the HTU on it.

Thanks this is the one I have.

I think that the to black once is pullup