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Build a WhatsApp like Chat app in Android & iOS & Know How WhatsApp Works Technically

WhatsApp is the most sought after messaging application that has revolutionized the messaging app market. Several attempts have been made in vain to clone WhatsApp as a chat app, but none of them yielded the result. Despite introducing similar functionalities, no chat app has ever been able to topple WhatsApp’s supremacy as a chat app.

In order to build a WhatsApp like chat application, one should have a detailed understanding of its functioning mechanism and technicalities.

How Whatsapp Messaging App is Working Technically?

create a clone app similar to whatsappWhatsApp uses Ejabberd (XMPP) server which facilitates instant message transfer between two or many users on a real-time basis. High reliability and sustainability even under peak traffic the reason why WhatsApp developers chose Ejabberd above anything else.

ERLANG is the programming language used to code WhatsApp. Code restructuring and some important changes were made to the Ejabberd server to achieve optimal server performance.

Further, Erlang is agile to adapting to instant updates and hot fixes. This is what helps WhatsApp to quickly push the changes to live implementation without requiring restarts.

1. Insights on data transfer in WhatsApp

how whatsapp works technicallyWhatsApp manages over 50 billion messages a day. The key to smooth data processing lies with the message queue length. The length of the message queue of all the processes associated with a node is monitored.

In case of multimedia messages, contents (audio, video, or image) are uploaded into a HTTP server and are linked with the content and then sent to the receiving node (receiver) in the form of a thumbnail. Based on the user’s preference the content can either be viewed or discarded.


2. Protocol used by WhatsApp

The primary protocol in use is XMPP (Extensible Messaging and Presence Protocol).DSL ensures network security and also helps in preventing private data transfer.

As and when message is sent, it is queued on the server. The message waits in the queue until the recipient reconnects to receive the message. As and when a message is delivered the sender gets notified by a double check mark near the message. After the delivery the messages are instantly deleted from the server memory.

This instant deletion from server memory helps WhatsApp keep its resources to a bare minimum.

Additionally, Whatsapp uses HTML5 WebSockets which communication technology which facilitates two-way communication.

3. Registration process of WhatsApp

Whatsapp Registration ProcessUsers can register for WhatsApp by entering their mobile number. On entering the number, the user will be sent a OTP which once verified by the device will initiate the user to the chat screen.

4. Database management

Mnesia DB handles the heavy-duty task of database management. Mnesia is a multiuser distributed DBMS which also happens to be the default DB of ERLANG. Mnesia helps achieve quicker request responses, thereby improving the overall efficiency.

FreeBSD is the OS upon which WhatsApp is built. Improvising on the ERLANG based applications and optimizing FreeBSD, WhatsApp is able to achieve better performance. For storing multimedia files, the app uses an exclusive web server YAWS.

build messaging app


Build a Whatsapp like Messaging App with Contus Fly

Having discussed the technicalities of WhatsApp it is time to shift gears over analyzing the possibilities of creating a whatsApp alternative. There are plenty of messaging applications in the market that appear to be perfect WhatsApp clones. The reality is many of the attempts of building WhatsApp like apps are failing because they do not follow the technical aspects.

Well, if we take such apps as an example, it might be quite difficult to understand as they are completely built products. Instead a ready made solution that can help in creating a WhatsApp clone app would be a better learning material.

Contus Fly is a framework that catalyses the build a chat platform. Contus Fly can be used to develop WhatsApp clone app for Android, iOS and Website platforms as it has the SDK ready for these widely preferred mobile operating systems. Since native coding has been used by Contus Fly to achieve better speed, it can be handy in developing a WhatsApp like native app.

Framework & Architecture of Contus Fly

contus fly real time chat app work flow


Ejabberd, the open source Jabber server has been customized by Contus Fly to improve operational efficiency. The XMPP protocol has also been customized to speedup signing in and re-signing in sessions. To protect the app from DDOS attacks and to prevent account spoofing, this mobile chat app solution has been encrypted with HMAC.

Mnesia and MySQL

For data storing, Contus Fly makes use of both Mnesia and MySQL. While Mnesia is used to maintain user login sessions, MySQL contributes in maintaining the user details, right from account credentials to other personal data.

Cassandra database

Chat logs are a key for instant messaging applications. In order to save chat history between several nodes, Contus Fly has deployed . This database offers a good read write speed thus helping users to retrieve chat logs as and when they need.

Amazon S3 bucket

Multimedia messages including audio, image, video are saved in Amazon S3 bucket. Registration for the app usage can be done in multiple ways including mobile number, email, user name password and social login.


WebRTC is a source code that is used to build real-time communication (RTC) in browsers and mobile app. Contus Fly has inbuilt WebRTC that allows its users to have VOIP (voice over the internet protocol) voice/video calls in their messaging app


Contus Fly offers a 3 layered security flow – end-to-end encryption, HMAC authenticated screening, and online/offline verification protocol; that ensures the data transmitted within the chat app is secure.


As and when a user triggers a message, the chat SDK sends a request to the Ejabbered server. In return the server checks for the availability of the recipient and if available, the delivery request is sent to the recipients SDK and then delivered. If the recipient is offline, the data is stored in the Ejabbered as message will be queued in the server.

Contus Fly Features

  • Group Chat
  • Offline Messages
  • Push Notifications
  • Presence
  • Social Integrations
  • Locations
  • Sync and Store
  • Voice & Video Calling
  • Video Conferencing
  • Multimedia Sharing
  • Easy Screen Sharing
  • Fully Searchable
  • End to End Security
  • Support

Uses Cases of Contus Fly

1. Build Your Own Chat App:

Contus Fly is a instant messaging solution that can be customised according to the needs of the user. The customizations are highly flexible and can be made both initially or even after the app is launched.

2. Chat API:

Chat API provides users the access to infrastructure of server. This enables any website or app to be integrated with a messaging solution that performs without any hassles and is highly scalable.

3. Messaging SDK:

SDK is an instant messaging framework that enables the app built with it to work on specific platforms. Contus Fly’s SDK has been built in an enterprise grade making it compatible on android, iOS and windows.

4. In-app Messaging:

A source to connect with your customers goes a long way. In-app messaging and push notifications initiates a direct conversation with app visitors and assists in providing accurate product explanation and suggestions.

Contus Fly – A Premium Solution to Create Real Time Chat & IM Apps

  • 100% Customizable Solutions
  • Multi Platforms Supports
  • Authenticates using Social Networks


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173 Comments on "Build a WhatsApp like Chat app in Android & iOS & Know How WhatsApp Works Technically"

Dai Software
6 months 8 days ago

Pleasant post, Thank you for sharing profitable data. I appreciated perusing this post. The entire blog is extremely pleasant discovered some well done. Thanks for sharing…Also visit my page.

Sundar singh
6 months 12 days ago

I want to create a messenger app so how can i utilize yours service.

1 month 18 days ago

Dear Sundar Singh,

With your given email address our business team will contact you shortly to discuss about your requirements.

6 months 14 days ago

I want to create app like whatsapp please give me support on this website:https://****.be/3vNwzP865Ko

1 month 18 days ago


It’s great to hear your requirements. Thanks for reaching CONTUS, our executive will be in touch with you for discussing more about this and it will be easy to contact you if you share your contact no and skype ID.

David Clark
8 months 26 days ago

Building a chat messenger like WhatsApp is an amazing and difficult task to be done, but you should also consider making a web version of WhatsApp with your mobile app to make it more usable for everyone.

Mark Robert
9 months 18 days ago

Nice Article you provide valuable content to us, keep it up. You’ve managed to make it readable and easy to read. You have some real writing talent. Let you see I have written similar content :

10 months 14 days ago

I like your writing style, I think if we talk about create app like whatsapp then you very well described all the necessary nuances and technologies, I am also interested in this topic and I think that this topic will not become obsolete for many years! I also think that the main task and the main problem in planning and development is the creation of unique functions for the application since the development of new functionality is always coming up with unique solutions!!

10 months 14 days ago

Query:- Whatsapp incoming messages are silent randomly, simulated in various phone models. Most of the time 1st message is silent. Message comes, icon shows up in status bar but no alert, no popup & no vibration. Is this a whatsapp bug or Android bug??

Matrid Tech
10 months 24 days ago

If you guys need some help from professionals, we are here to help you with affordable prices. Check the website. you will love our services:

Jhonny Henderson
10 months 30 days ago

Whatsapp is a very useful app nowadays but it also has some limitations. If you want to develop any chat app you can visit chat app development

11 months 26 days ago

I want to create a application that that is more of whatsapp application,please can you give me the quotation

Techto Review
11 months 27 days ago

Here, we have a discussion on how to save WhatsApp status. So, for this, you have to need a file manager app to do this process.

Deep Maurya
11 months 27 days ago

This is great blog post on Build a WhatsApp like Chat app in Android & iOS & Know How WhatsApp Works Technically. Want to know how to create custom app here is way to know:

1 year 29 days ago

Hi Rama,

I want to create an app like whatsapp with some other features, please give me quotation on this and give some overview, what you’ll give support to us

Krunal Bhalala
1 year 2 months ago

We want chat app please contact

1 year 3 months ago

I am interested in developing like WhatsApp style application with chat, video, audio and payment processing integration. I saw you have a sdk and also offer development support and will like to discuss my project further.
Please let me know how to move forward.


Chhaya Jaiswal
1 year 3 months ago

Looking for whatsapp kind of application, with Voice call, video call, Chat mesaging which can be customizable. This also should handle a high loads of calls & video calls.
1. want to understand the price of the app alone.
2. Want to know if you handle the cutomization of the program, what would be the hourly pricing for it?
And do you write NDA for the customization of the code?

Daniel Dodani
1 year 3 months ago

Need to know some codes from your end to finish my android app

1 year 4 months ago

I am developing a solution to existing website. I need to add: whatsapp notificaciones, videochat (2 persons in a room), chat inside video chat room. I want to know what you offers and pricing.

Raju Shahi
1 year 4 months ago

Simplay i want chat and video call sdk(like whatsapp, hike) for my android app lets discuss and get details

Thank you

Kaushik Kannan
1 year 4 months ago

I’m creating a chat-based project management tool platform like WhatsApp for businesses. So tell me what you guys can offer me from the development perspective.

3 years 11 minutes ago

can u please help me in code of how to send push notifications from ejabberd server to android app when app is offline like we receive notifications in whatsapp and facebook