This article explains how to know which friends are active on Facebook Messenger.
Steps
Method 1 of 2: Using a Mobile Phone or Tablet
Step 1. Open Facebook Messenger
The icon looks like a blue speech bubble containing a white lightning bolt. It is located on the home screen or the Applications screen (Android).
If you are not logged in, follow the instructions that appear on the screen
Step 2. Tap the contacts icon
It looks like a bulleted list and is at the bottom of the screen, to the right of the blue circle.
Step 3. Tap Active
It is located at the top of the screen. This list shows all active friends on Messenger. If a user is online, a green circle will appear on their profile picture.
Method 2 of 2: Using a Computer
Step 1. Type https://www.messenger.com in the address bar
It is the official application of Facebook Messenger.
Step 2. Log into your account
If you have already done so, you will see a list of the latest Messenger conversations. If not, click on "Continue as [your name]" or enter your login information as requested.
Step 3. Click on the blue gear icon
It is located in the upper left.
Step 4. Click Active Contacts
You will see the list of your connected friends.