Send Notifications to Your Phone From an ESP8266.

Every now and then it would be useful to get notified on the phone about events in your Arduino code. The ESP Notify Android app and it's corresponding arduino library allows you to achieve that with ease and can send notifications from any ESP8266 platform like NodeMCU, Wemos D1 mini and other Arduino compatibles based on the ESP8266.

Step 1: Add the App to Your Android Phone.

Add the app to your phone by going to
https://play.google.com/store/apps/details?id =com.espnotify.rpi.android.espnotify
and clicking "install".

Once you have the app installed you need to open it and log in with your Google account.

Step 2: Getting the Tokens and Installing the Library.

Once you are logged into the app you can send yourself the necessary tokens via email by clicking the button "Send Tokens". Then you can open the email on your computer.

The email contains your Device_Id wich you will need for your Arduino sketch, and this link to download the Arduino library:
https://github.com/4rtemi5/ESP_Notify/archive/master.zip

Once the library is downloaded you can add it to your Arduino IDE by clicking on Sketch>Include Library>Add .ZIP Library in the IDE and then selecting the downloaded ESP_Notify-master.zip file from your Download folder.

If this succedes the Library should be available to your Arduino IDE.

Step 3: Configure and Try Out the Sketch.

Now you can load the simple example sketch that comes with the library. You do this by going to File>Examples>ESP_Notify>send_notification.
Everything you have to do to make this sketch work is insert your WiFi SSID (name) and WiFi password and copy your Device_Id inside the parentheses next to DEVICE_ID.

Then you can selcht your ESP8266 platform under Tools>Board and select the Port to wich is attached to your computer.

If you have not yet added the ESP8266 boards to your Arduino IDE you can do so by copying the following Url to your boards manage that is located under File>Preferences>Additional Boards Manager Urls:
http://arduino.esp8266.com/stable/package_esp8266com_index.json

As soon as the device is done uploading it will start blinking while it is connecting to your WiFi network and once it is done will send you a notification to your phone!
Congratulations!