All you need to know when building a secure messaging app like Signal?

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An environment is building up with a general air of suspicion around all digital communication channels. People are becoming more aware about their rights over their data and have realized just in time that their communications are private and they should remain private.

Masses and governments have been discussing on such sensitive matters from time-to-time but the recent WhatsApp Privacy Policy has ignited the torches once again.  Normally what would be a regular policy update made to headlines across the world, not something you see every day but why?

Current Market Share by Popular Messaging apps

Turns out, WhatsApp is the largest messaging platform around the world! About 2 billion users are currently using WhatsApp and any changes in the WhatsApp’s privacy policy are going to effect 25% of the world’s population. That is not something very easy to digest.

Then ranks the Facebook Messenger with 1.3 billion monthly active users according to a study by Statista. Next comes the Chinese WeChat with more than 1.2 billion users. WeChat is followed by Snapchat and Telegram with around 400 million active users.


These number are expected to rise further because smartphone adoption is still on the rise. There still are many parts of the world where smartphones are unique or newly introduced. Mobile internet is still improving and there are thousands of areas where mobile internet access is still on its way.

Ideal features of a great messaging app

The world of software is one where you do not have any set protocols and parameters. You can choose to develop whatever you think the user will need and can help to solve his problem.

When it comes to messaging apps, there are certain expectations established over the years about what a messaging app will include. It has more to do with what the current big-fish companies in the market are offering in their apps. The user has grown so used to their features that any new messaging app he will switch to, will be measured relative to WhatsApp and Messenger.

Let’s look at some features that will be demanded from any messaging app today.

1.    Account and Signup

It is important that a user should be able to make an account in the messaging app. This allows to not only establish a profile, it will also ensure that his messages and conversations can be stored remotely linked to his account on a server, a company server or the user’s own cloud.

Such a sign-up process will allow the messaging app to be accessible from any device the user wants, a phone or a computer without any hassle.

2.    Interactive Chat box

The chat box experience is important because this is where the customer will spend the majority of his time. This experience needs to be attractive for better user retention because if the user likes the chat experience and features, he will not shift to any other app unless needed.

The chat box functionalities to include in the messenger app should include but not limited to the following:

a.) A simple feature of showing when your message was sent, when it was delivered, and when the user actually read it. This makes things easy for the user because unlike SIM sent SMS messages, the user can easily know if his message was actually conveyed to the recipient or is still sitting in his notifications.

b.) The chat box should be interactive to share feelings and emotions. By no means should it feel as if you are writing letters in the 1960s. The app can have its own sets of emojis and stickers for this purpose.

Generally, apps outsource such activities and cash them as a means of their revenue by including paid sticker packs. GIFs have been around for a while now but it is virtually impossible for any app to maintain an A-to-Z complete GIF library. The messaging app integrates another GIF platform’s functionality in their app. In this way, the user gets to use GIFs as well.

c.) The idea of tagging messages is not very ancient. Swiping to answer a specific message the other person sent is very convenient in a discussion when it is very likely that the user loses track of the conversation. It also becomes very easy to recall a message and you do not have to spill the entire chat upside down to look for and refer to a previous message.

d.) A facility to import contacts is very handy for a new app because the user is new to the platform. It might take a while for him to figure out how to reach out to his contacts on the new app. Importing contacts and showing clearly who is available on the platform and who is not solves the problem to the extent that he does need to save his contacts all over again.

It also works as an advantage for the app company because they can send invitations via the user and thus, promote their app-based upon the user’s need to communicate with his relations.


3.   Security Measures

Data privacy and secure communication are important. No user wants his messages to be read by any other third party or they should be used to show him ads all day long. While WhatsApp still maintains the end-to-end encryption, the recent policy update has clearly stated that the company can use the user’s data however it wants. After accepting to continue with the app, the user puts his privacy at stake. It is understandable that the companies need a profitable business model as well but using user data and sharing it with third-parties is not the right way.

4.    Voice and Video Calls

Good quality voice mails and video calling features are a must these days, especially after the work from home transition. These will add to the user retention because they would not have any excuse of leaving the app, improving its engagement.

How to build a secure messaging app like Signal?

Building an app that can compete with Signal or WhatsApp or Facebook Messenger can be tough for 3 reasons:

I. These companies have years of user’s data and experience. All their features are tried and tested by user’s and they rely on these apps for their everyday communication.

II. Signal has been around since 2014, initially in form of other apps and then under the name Signal. Today’s Signal apps has over 6 years of optimizations and bug-fixies and there is no alternative to experience theoretically.

III. User’s have years and years of their chats and conversations stored on their messaging app accounts and surely, they would not be ready to migrate that easily. Besides, apps like Signal have a reputation in the market which cannot be achieved by pulling all-nighters. You have to wait for the user until they confide in their trust in your app.

Following is our guide to how you can build your own secure messaging apps:

Special Attention to Security

Remember, it is data security and an insult to the user’s privacy that WhatsApp is being criticized and substituted.

Just for a replay, WhatsApp was the first to introduce end-to-end message encryption. This means that the message can only be viewed in two places; the sender’s phone and the receiver’s phone. It was a company that people trusted for safe communication.

Providing the same level of confidence to your users is important for them to trust you because they are better informed today and realize that it is those who have to guard their data’s security.

There a number of strategies that can be opted to ensure that all communications happening through your app are secure.

1.) Opt for end-to-end encryption so the user knows that the information they share is theirs and no one else has unnecessary access to it.

2.) You can consider publishing your source code online as Signal has done on GitHub. This allows developers to view the code and they can easily check whether there are any loopholes the messaging app has left out that can help in the extraction of data.

3.) Independent code audits are important because I can claim anything for my products. The opinion of any independent third party matters because they are impartial to the outcomes. Their opinion will have a significant impact on the users for two reasons:

3.1.) The user will know that they can trust the company because of another independent expert in vouching for them after the examination.

3.2.) The practice of audit itself is a strong security check that the messaging app company is open to examination and is confident enough to ask an independent party for a review.


The Security Scorecard

Promatics have prepared a security scorecard based on guidelines provided by Surveillance Self Defense that provides a unique comparison of Signal with many of its competitors.


This comparison clearly indicates that Signal can be trusted in terms of data security and privacy because it surpasses all of its competitors in terms of security measures. You would definitely want to consider these criteria for your messaging app.

How Promatics have built a similar app before?

Promatics have built many messaging apps since 2015. Being an independent technology provider we build such apps for our clients that satisfy the above criteria. The App was built Native for Android users and used secure databases, RESTful API, and XMPP messaging protocols to ensure that the data was transmitted securely. The Firebase Cloud Messaging allowed the users to view their messages right away as soon as they were received.

An analysis of the reviews on the app showed that users were very concerned about the security of their information especially photos. Effective security protocols were a major reason that they chose to transfer to the app for their friends and family circles.

Within 4 months, it was over 5,00,000 downloads in a prominent south Asian country. That was one of the most successful messaging apps we have built. The client sold the app to a social media network in their country which integrated the whole concept in its parent app.

Is making another-Signal worth a shot?

Absolutely yes. The acquisition of WhatsApp by Facebook raised concern among the internet community along time ago that WhatsApp may not remain entirely reliable in a short time. This became clear with the new privacy policy that indicated that WhatsApp can use data from a user’s smartphone and location for its purpose and the user agrees to such usage.

A huge market gap has been created. This is the perfect opportunity for anyone who wants to develop a messaging app. The big boys are in for a down-slope ride. Someone is going to take the chargeback at the top.

As developers, trust is a sacred possession that the users entrust to us and we must ensure that we hold it strong at our end.

Ready to Take the Next Step?


Rahul Singh

Sr. App Developer

Rahul has been associated with the apps industry for more than 9 years now. He has seen the apps economy grow from its nascent days to a full fledged industry with its complete ecosystem as of today. His interest lies in pursuing and getting to know the best app development technologies, processes and platforms. He is truly an app enthusiast. In his free time he loves playing console games and reading history.

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