Rui Santos over at Random Nerd Tutorials posted a step by step guide on building an ESP8266 Wi-Fi button:
In this project you’re going to build an ESP8266 Wi-Fi Button that can trigger any home automation event. This is like a remote control that you can take in your pocket or place anywhere that when pressed sends out an email. It can also be called a DIY Amazon Dash Button clone.
Check out the video after the break.