How Much It Cost And How To Build Mobile App Like WhatsApp?

How Much It Cost And How To Build Mobile App Like WhatsApp?

10, August 2018, 4:00 PM

As we have discussed in the previous blog, why Whatsapp is the most preferred chatting application of all despite other famous chat apps? 7 out of 10 people uses Whatsapp; the majority of the population use WhatsApp at least once a day. As discussed in the previous blog features are the key to its success.

If you are a developer or a business-preneur, many of you might have questions, how to build an app like WhatsApp? What technologies do we require? What is the development cost of such chat apps? So today we will try to get the answer on this blog.

As like every other application Whatsapp also has flow. I have tried to cover all the details and will explain to you with help of images also.

Registration process

First, the user needs to register using the mobile number which is then verified using verification code. You can use AJAX  to create signup and login in such chat apps.

Design Of an Mobile Application

Let have look at the technologies used:

Languages like PHP, Java, and Erlang is used to build chat apps like Whatsapp, Wechat. Whatsapp used Erlang as a programming language. Chat apps like telegram used Node.js. Though Whatsapp used Erlang; Node.js is also a better option as a single language can be used in both; front end and back end. Another benefit of using Node.js is that it is cost-efficient as compared to Erlang.

Notification Generation:

We get a notification on receiving messages even if we are not using the app, it is being done with HTTP and Push notification.

Double tick shows that the message is received by the receiver and blue tick tells that the message has been read by the receiver. XMPP Extensible messaging and presence protocol is used to achieve the functioning of push notification.

If you are sending a message to someone the message gets queued and as soon as the receiver gets reconnected to the internet, he will receive the message and you will get notified by the double tick. These messages are queued in the server until it is being sent, as soon as the message received by the receiver, it is deleted from the server.

Media Files & Database:

All the files, documents, and multimedia that are running through app need to store in the database. Whatsapp uses Mnesia database. It is very important to have a database.

Whatsapp- App Design

Security (End to end Encryption):

Many companies provide encryption where they have the key to decrypt but, the end to end encryption, the company does not have the decryption key. Only the Two people who are chatting can decrypt the message.

There are two types of a key for every user; Public key and a Private key. The public key is open to everybody but the private key is not accessible. At the end to end encryption; If you want to send a message to a person you will use the public key of that person, this message is encrypted and then send. No one can decrypt the message except the person having the private key. In the same way, the other person will send you an encrypted message using your public key.


Even after the features that Whatsapp provides, there is much yet to come in near future. There are many more things Whatsapp may add in its next update like:

Very often; while typing we do type mistakes, what if Whatsapp can analyze the response that should be given to the person you are talking to automatically and you just have to tap on whatever option you want to pick. So basically no typing mistake and no fuzz of typing. Add on option like “My Contacts except” will add more dynamic to the application.

Now the main question what is the cost of building chat apps like Whatsapp?

Cost depends on the complexity, time spends and other parameters to build the app. You will need a team who can work on. Building an app like Whatsapp may cost up to $30k. The cost depends on the features, on adding features the cost will be more than $30k.


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