How to enable Firebase server on IM App:

• Go to Settings in IM App on AdminCP and select "Firebase" at setting Select chat server

• Add Firebase Config Object (Required)
• Add Algolia App ID (Optional) and Algolia API Key (Optional) to support search messages

Setup Firebase App:

1. Add Firebase project

• Go to Firebase console
• Select Add Project if you don't have one
  
  
• Go to App Dashboard, select Project Overview > Project settings 
  
  
• In Your apps section click on icon </> to Add Firebase to web app
  
  
• Add App nickname, then click Register App, then click Continue to console to back to Project Settings page
  
• In Your Apps section, chose the app you just created, then click on Config and copy all scripts code on it.
• Paste to setting Firebase Config Object in IM App.
  

2. Enable Firebase Database

• Back to Firebase App Dashboard, select Develop > Database.
• On the section right click on Create Database.
• Select mode and click Enable
  
• After enable, you will redirect to database page. 
• In that page, select tab Indexes and add 2 Composite indexes to Database by click on Create index manually. 
• Setting like 2 below screenshot:
   
  
• Indexes enable:
  
• You must enable Sign-in method Email/Password in your project Authentication to allow users access to the database, follow screenshot:
  
• Then, go to Database > Rules tab and set up database rules like:

Now, you can start to use IM App with Firebase.

Setup Algolia to support search messages

• Go to Algolia App Manage, sign up if you don't have an account
• Algolia is pay to use, so you should check their pricing at Algolia Pricing
• Go to your app Dashboard
  
• Select Indices, create new Index with name im_chat
  
• 
  
• After Create Index, select menu API keys on left
• Copy Application ID and paste to setting Algolia App ID on IM App
• Copy Admin API Key and paste to setting Admin API Key on IM App
• 

Now, users can search full-text messages with IM App and Firebase