This article explains how to know which friends are active on Facebook Messenger.
Steps
Method 1 of 2: Using a Mobile Phone or Tablet
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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
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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.
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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
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Step 1. Type https://www.messenger.com in the address bar
It is the official application of Facebook Messenger.
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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.
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Step 3. Click on the blue gear icon
It is located in the upper left.
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Step 4. Click Active Contacts
You will see the list of your connected friends.