I have come across the Espduino library but I am having no luck with it at all and if preferable I would like to keep the pro mini's serial port free (for future programming and other bits). I have however been able to mimic the SparkFun WiFi shield but that's not working well with the PubSubClient library at all.
Is there a library or any tutorial to point me in another, preferably working, direction. I cannot remove the pro mini as the ESP lacks enough I/Os. I did look into I2C but with that the ESP cannot be a slave which is what I would want.