How was WhatsApp Developed?

The idea of instant messaging first started in 1961 when the Computing Center at MIT – Massachusetts Institute of Technology – created the Compatible Time-Sharing System (CTSS). This system resembled today’s email services and allowed up to 30 users to log in simultaneously and message each other. Not surprisingly, this new system was an absolute success. So much so, that by 1965, hundreds of MIT and New England University students were already registered users.


How was WhatsApp Developed CTSS

Source: Slideshare


Today, instant messaging is an important part of our lives. In our work, we use emails and platforms like Slack, Microsoft Teams or Neo. As for socializing, we literally have thousands of apps to choose from. However, by far the most popular instant messaging app today is WhatsApp with 2 billion monthly users. In comparison, Facebook’s Messenger takes second place with only 1.3 billion. And this brings us to the topic of the day – how was WhatsApp developed and how did it become the top most used messaging app today?


Establishing WhatsApp Inc.

When we look into the history of how an app or company was developed, there is always an interesting story. And most times, it’s the right man at the right time. With WhatsApp however, there are a series of events that led founders Jan Koum and Brian Acton to build the world’s most used messaging app. 


How was WhatsApp Developed Brian and Jan

Source: The Daily Sun


Jan and Brian met in 1997, while Brian was working as a software engineer at Yahoo. The two liked each other and became friends. Soon after, Jan also joined Yahoo, as a Security and Operations Engineer. They continued working together until 2007 when they both quit their jobs on the same day


At the beginning of 2009, Jan bought a new iPhone, and the fact that he kept missing phone calls while at the gym started bothering him. Coincidentally, around the same time, Jan and Brian both applied for jobs at Facebook, but ironically, Facebook rejected them. 


His frustration with his new iPhone, and the fact that he was still unemployed paved the way for a new opportunity. He wanted to build a “status” app that would show people if you’re available for a call. So, on the 24th of Feb 2009, on his birthday, Jas established WhatsApp Inc, and everything became real. 


WhatsApp is Born

Jan was confident he could build the backend for the app, but he still needed an iOS developer. So, one of his friends, Alex Fishman, suggested Russian iOS developer Igor Solomennikov. Only a few months later, the first version of WhatsApp was approved by the App Store. Needless to say that Jan was ecstatic. 


Until he realized that no one was using the app, that is… Jan was so upset that he almost dropped the idea. However, Brian encouraged him to “give it a few months”. Brian’s commitment, encouragement, and positivity made him an important part of the new company. So, in November 2009, he joined Jan as co-founder.


Not long afterward, iOS 3.0 introduced push notification, and Jan got his break. He and Igor updated the app and pushed the now v2.0 to the store. The new app was working as intended and Jan’s vision became a reality. However, as it often happens, people started using the app in their own way. In the beginning, they would send joke updates like “I’m on my way” or “woke up late”. And soon after, people started actually chatting with each other through the app.


It was then when Koum realized he accidentally created an amazing app – a social app, that connected users instantly, no matter their location, for free. Also, unlike with G-talk – now known as Google Hangouts – or Skype, WhatsApp users logged in with their phone number. There is no need for a username and password. In Jan’s own words “it just works”. But, more importantly, WhatsApp promised discretion. Their messages were not stored and the user data was kept safe.


WhatsApp’s First Steps

By the end of 2009, WhatsApp now had 1 million users. All of this, while investing $0 in advertising or promotion. The incredibly rapid user growth, combined with constant requests from different users convinced Kaum that the future of WhatsApp is cross-platform.


However, since the company adopted its famous “no ads, no games, no gimmicks” approach, they had no revenue stream. So, during the 6 months after the app’s launch, WhatsApp tried several payment plans. Initially, they decided on a one-time download fee that seemed to work. Later on, this strategy switched to a subscription-based plan, where users would get the first year free, and pay $0.99 a year after that. 


How was WhatsApp Developed 2010 2015 2020


As it turned out, this strategy worked well for WhatsApp and by the end of 2011, they already expanded in almost 70 countries. More importantly, the app was available on all mobile platforms of the time – including Android, iOS, BlackBerry, and Windows Phone. WhatsApp was now growing at an even faster rate. So much so that in October 2011 it registered 2 million messages sent in just one day


Facebook buys WhatsApp

WhatsApp was expanding faster than any other platform at the time. Already by April 2013, they had 200 million users. In just one year after that, 300 million more users joined. However, as the app remained add-free, the company was running at a loss. Nevertheless, its vast amount of users and its clear potential attracted the attention of the world’s most popular social network, Facebook.


In February 2014, Facebook bought WhatsApp for $19.6 billion, more than the $16 billion WhatsApp was asking for. The extra payment was an incentive for the founders, so they would continue working for WhatsApp under Facebook’s umbrella for at least four years. As a result, through the acquisition, Jan Koum joined Facebook’s board of directors.


From WhatsApp’s list of demands, Facebook was required to maintain the integrity of the app. This included the end-to-end encryption, the no ads policy, and overall user data privacy rule WhatsApp applied so far.


WhatsApp under Facebook

From 2014, when Facebook took over to 2016, WhatsApp user numbers grew to an impressive 1 billion. And topping things up, in 2016 WhatsApp drops the subscription fees altogether becoming completely free-to-use.


Also in 2016, WhatsApp announced that it finally fully successfully implemented the end-to-end encryption system. This was the most desirable feature at the time, especially after the Cambridge Analytica fiasco.



However, are not always what they seem. Especially when speaking of tech giants like Facebook or Google. The same year, Facebook announced a change in its terms and conditions, stating that WhatsApp user data will now be combined with Facebook user data. Their reasoning at the time was better targeting for advertisement. However, this went against the beliefs of both Brian and Jan, and, as a result, Brian quit in 2017 and Jan resigned the year after


In 2018 WhatsApp launched WhatsApp for Business on Android, aimed at small businesses. The new service was part of a new revenue stream and included a company profile, as well as a company chat.


WhatsApp today

While Facebook took a hit over the user-data controversy, WhatsApp’s development seemed unphased. Their usage and user base saw constant growth, reaching 2 billion active users in February 2020.


Today, the most important aspect of WhatsApp remains the end-to-end encryption. However, their’s features extend far beyond the original safe text function. Among others, the app now allows group chats, quick moments sharing, and document sharing. WhatsApp also supports video and normal calls, as well as voice messages. And, probably the most unexpected development, WhatsApp is now available on desktop too!


Technology behind WhatsApp

WhatsApp is based on Erlang, a programming language designed for scalable systems with real-time high availability requirements. From the beginning of WhatsApp, Erlang seemed like the perfect fit. Erlang is simple but highly functional and supports automatic memory allocation for improved performance. Also, Erlang is able to detect failures within other processes or other computers. Their servers use the FreeBSD operating system.


On the functional side, WhatsApp also uses a variation of XMPP – Extensible Messaging and Presence Protocol. Breaking down the abbreviation, extensible messaging means that applications using XMPP are scalable and allow users to see the actual instant message. The protocol – which is a set of standards – makes possible the communication between different systems. And finally, the presence part updates the servers regarding a user’s status – online, offline, busy, etc. In simple terms, it is what makes WhatsApp the socializing app that it is today. This is used along with other standard protocols such as TCP, SRTP, and SPL.


The end-to-end encryption is done by the Open Whisper System. This is an open-source protocol ensuring that messages of any kind – text, media, voice, etc – are only seen by their intended receiver. As WhatsApp explains, not even they have access to your conversation. 


How WhatsApp’s end-to-end encryption works

There are many instant messaging applications using XMPP out there. However, what sets WhatsApp apart is the encryption function. More precisely, how the whole system works together. So, what happens when User A sends a message to User B?


First, the server confirms the identity of User A, then adds the message into User A’s “sent” file. Then, the whisper protocol encrypts the message and sends it to User B. the system will continuously send the encrypted message until User B’s device receives it. Onc the message is received, then the servers confirm User B’s identity, and decrypt the message which is finally placed into User B’s inbox file. When User B replies, the whole process starts all over again. And the coolest part is that this whole journey happens in milliseconds!


What’s next for WhatsApp?

This year has been busy for WhatsApp, as they made a few changes, including the new dark mode. However, WhatsApp still has some aces under their sleeve. For one, we should shortly expect a new “delete messages and a closely related function is the “expiring” messages.


How was WhatsApp Developed Delete Message



Basically, the two work more or less the same. However, the Delete function allows you to set a “timer” for each chat. But, the Expiring messages controls all of your chats. Finally, we will soon be able to use WhatsApp on multiple devices at the same time. However, the most important aspect of this feature is that it will work on tablets as well as other mobile devices.


These features are still in Beta testing and we do not have a release date for them. However, we are surely looking forward to learning more about them as soon as WhatsApp releases more information.



WhatsApp started from an idea, an opportunity, and a dream. However, it was Jan Koum and Brian Acton’s integrity, loyalty, and respect for their users that brought them the attention and love the app deserves. Their unique no add, no games, no gimmicks approach earned WhatsApp a special place in their users’ hearts. And we can see that from the steady user growth even as Facebook was struggling with the controversy around their user data leaks.



We think that an important lesson we can learn from WhatsApp’s story is to always put your users first. They are the power that drives your machine. And as long as you have dedicated users, you can grow to enormous proportions without ever easting time on ads and promotion.

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