How to find your User ID in Agar.io

In case you need to contact Customer Support, make sure you provide the User ID you are using in the game.

Web:

You need to press the settings cogwheel in the main page of the game:

Your User ID will be in the next page, also, with the version of the game:

Mobile:

You need to press the profile button in the bottom right of the main page:

Your User ID will be in the next page, with some profile information:

To find your longer ID, go to Settings and scroll down: