How to Make a Simple VoIP Mobile App?

Just imagine what options the modern world presents to us... Once upon a time, we didn’t even dream about making a voice phone call! And now? Emails, instant chat messengers, Voice over IP (VoIP) and video conferences via mobile apps... Particularly VoIP, in fact, was a real trailblazer in the field of the recent telephone industry modernization.

Today, it’s an integral part of all kinds of business companies. Constantly rising increase of the VoIP usage and unique abilities it provides present an exceptional opportunity for mobile app developers and startups. Wanna know why? Join us for an excursion!

VoIP. Getting to know the technology

Long story short, Voice over Internet Protocol stands for an integrated IP-based technology that lets us make and receive calls via the Web connection (Wi-Fi). Unlike a traditional telephony, in the VoIP, a voice traffic is presented by multiple discrete data packets and their real-time transmission over the local area networks (LAN), public wide area networks (WAN), or by the chosen Internet Telephony Service Provider (ITSP).

It includes various kinds of communications services, like voice calls, faxing, SMS, and voice messages. And ITSP, in turn, works with the help of circuit protocols of the Public Switched Telephone Network (PSTN). One more significant ability of the Voice over IP is that it can easily handle a couple of conversations and different data types over a single line.

So, basically, if you’re wondering how to make a voice call through the Internet, the line of work consists of the following steps:

VoIP steps

Quick History Facts

First, there was just a simple PSTN: the good old reliable landline telephone system that transmitted analog voice data via copper wires. In the early days, it even needed the operators to manually connect pieces of those wires on a switchboard, for every individual phone call to happen. It was expensive and exhausting service.

But then, things had started to change, and somewhere over the 60’s the tendency focused on an automatized switching, so that a couple of calls would share one line. Nowadays, PSTN is digitized, yes, but the process is still carried separately from the Web traffic.

Then, in 1974, a first attempt of the VoIP call was made by ARPANET, but the technology as we know it was invented long after by VocalTec company in 1995. It started as a simple home project in Israel, however, became a pioneer with its first widely used “Internet Phone”.

Old type of phone connection

In the late 90’s the economic situation and hardware cost changed the customers’ attitude and the Voice over IP calls seemed like a reasonable cost reduce for both users and entrepreneurs. This is when the era of the VoIP revolution all around the world has begun.

Starting from the early 2000s, the quality and connectivity of the calls improved thankfully to the broadband Ethernet. Those years presented a unique gift to the humanity – the Skype company, who changed the VoIP industry forever. With their video conferencing option Skype became a must-have and reached the top of the market.

These days, we have one more precious creation from them – Skype mobile app. A useful tool not only for custom users but for the businessmen as well. And today, the VoIP the technology has evolved so much that it now powers dozens of the apps that provide rich communications options.

Why should you develop a VoIP mobile application for Business?

For starters, the growth of the market statistics in the last three years is impressive, indeed. According to the current numbers of the VoIP residential and business telephone lines in the US, it’s safe to say that service providers are happy people. More so, it was suggested to be 76.6 for residential and 41.6 million subscribers for business lines by 2018.

Okay, but why do we like that technology a lot? The first obvious reason is that because of the Internet backbone and not a PSTN, the price rather cheaper than calls via a landline or cell phones. Most of the time we can make those IP-calls for free even. Sure, but what other perks are there for those who want to implement the voice calls option in the mobile app?

The Benefits of the VoIP

1. Less money, more features

All just for the justifiable monthly fee: wireless lines, digital faxing, cheaper long distance and usual calls, reduced monthly telephone bills, lower cost for International calls, no additional long distance charges for unlimited monthly calls to certain locations, virtual numbers, voice mails, automatic call forwarding, portability (LNP) etc. So, you save money but increase the revenue. No unnecessary expenses – total win-win.

2. Efficiency & Flexibility

Not only VoIP simplifies the situation when the companies have to work from different sides of the globe. With a steady Internet connection calls have an exceptional quality, and multi-party audio or video conferences allow workers to actually see each other during some negotiations, therefore, make wise business decisions.

In short, thankfully to VoIP’s universality and constantly evolving hardware, you’re available to your partners and friends at any time of the day and night. Just think of it, how much money do you save, when participating in real-time meetings online without the need to fly across the world.

3. Improved Employee Hiring & Maintenance Issues

You don’t need a candidate who isn’t qualified for the job you offer or isn’t fit for it, right? So, with the VoIP technology, in those cases, when you need some advice of your HR expert who isn’t there for a period of time, you can easily send him/her a recorded interview with the candidate to get the needed help.

From the other point of view, VoIP, in fact, has the Internet backbone, so there is almost no maintenance for managing the lines required. This significantly reduces maintenance expenses and pump up business productivity in general.

4. Up-To-Date and High-quality Telephony

Yeah, we’re still pretty dependent on the PSTN, but it’s a fact that VoIP is getting more and more reliable with each year thanks to constant updates. It easily and efficiently handles heavy call volumes, as well as disaster recovery. There are also cool features like echo cancellation and noise detection, so the IP-based technology offers nice audio and video quality in contrast to traditional landlines or wireless networks.

5. Super Advanced Call Management Tools

Along with such features as Skill-based routing and Hunting Lists that ensure a faster answer for your business calls, VoIP services also provide you with the built-in analytics tools. Those give you invaluable insights on where you need to take a closer look in order to improve your business communications.

If you’re dealing with a Customer Relationship Management, there is an option for you to integrate it with the VoIP system. It’ll allow streamlining customers’ interactions, by instantly linking the callers to their profiles, for example.

VoIP Benefits

Voice Calling App. Some Tips Before You Start Development

So, time to dive deeper, agreed? Before hitting hard on the Voice over IP business decisions, it would be wise to have some lessons on what you’re going to face because it’s not an easy walk in the park.

1. Mobile Platform and App Type

As with any application, you have to choose the platform you want it work on, taking into consideration all the fact about your target audience, the Marketplace, and the desired complexity of the final product. Also, there is a point of cost spendings, iOS and Android take different time to make, not to mention the number of developers and their hourly rates. So, you have to define what exactly do you want to build and for what purpose.   

As for the types of VoIP apps, there are variety of them, so decide what features do you need and then look for the categorization:

  •  Free;
  •  Paid (IP PBX);
  •  OS-Based;
  •  Web-Based;
  •  Service-Based;
  •  SIP-Based.

2. Technology Stack – what do you need to learn

To be able to understand what you’re trying to make, get yourself familiar with the following:

  • How does PBX (PABX), switchboards, and telephones with hard wire work
  • The way Analog signals is being transformed into Digital ones
  • The basic of TCP/IP and network technologies
  • How to exclude the latency of real-time telephone conversations
  • Session Initiation Protocol (SIP) and Trunk (control the state of the session) – these protocols are based on a request/response transaction model.
  • UDP protocol (handles the audio with codecs)
  • IP-PBX (Asterisk)
  • STUN servers

VoIP Features

A) When one desires to build a VoIP calling app for Android

You’ll need basics like:

  • Java programming language and JDK.
  • Android SDK & NDK
  • Voice Quality Enhancement
  • A tool for bindings between the C/C++ library and Java code
  • A parser tool to parse the interface file before generating those bindings for the application.

B) When your choice is to create a VoIP calling app for iOS

  • Swift of Objective C language
  • Native iOS library with API
  • VoIP Stack and Voice Quality Enhancement
  • Narrowband and wideband voice codecs
  • Echo and noise solutions

C) For both platforms

You have to build a secure product with data encryption, so, there is a need for SSL/TLS protocols that support:

  •  Server and client side;
  •  (EC) DHE suites;
  •  Client certificates.

Then, choose the Open-source multimedia communication library with implemented standard based VoIP protocols (SIP, SDP, RTP, STUN, TURN, ICE). The easiest way for you, actually, to look for third-party services built on WebRTC platform, that provides all that infrastructure.

Here are some of them widely recognized among developers with nice tutorials and documentation:

  • Twilio
  • Sinch
  • TokBox

3. Features You need to Implement

For a really simple VoIP Mobile App you gonna have to deal with the next:

  • Make & Receive Calls
  • Send & Receive Messaging Calls
  • Conferences & Group Chat
  • File Sharing Option
  • Caller Profile (ID) & Multiple Numbers
  • Voicemail to Email & Call History
  • Contact List
  • Call Waiting, Hold, Blocking & Auto Call-back
  • Redial & Music on Hold & Mute
  • 911 Emergency
  • Call Forwarding
  • Geolocation
  • Time and Call Status
  • In-app Registration & Analytics
  • Credit Card Payments
  • Speakerphone & Recording Storage
  • Buy Local Numbers
  • Text-to-speech transformation tool

VOIP Features

4. Steps on how to make a VoIP app

Usually, the line of actions to create such product holds following code stages:

  • Setup a New Project
  • Adding a Login
  • Adding a CallScreenView Controller
  • Call Screen Implementation
  • Make Outgoing Call Implementation
  • Answer Incoming Call Implementation
  • Hanging Up The Call Implementation
  • VoIP Notifications
  • Test The Application

VoIP Drawbacks. What Difficulties Will You Face? 

And of course, there is no such project where you wouldn’t be pushed against the wall with the need to solve some problems. So, working on a VoIP application, you’ll have to avoid some common pitfalls to make your development process run more smoothly.

Mainly, the difficulties are:

  • Voice Quality Issues

VoIP technology has many improvements to do on Quality of Service (QoS) because it still depends on such factors as a broadband connection, hardware capacity, the destination of calls etc.

There suppose to be no delays, noises, and echoes in order to differ your service from the usual landlines. With all that Internet traffic being routed and sent via numerous paths, there could be temporary troubles for your users, like static, call drops and occasional audio problems.  

  • High Dependence on the Bandwidth

We describe the Internet with its bandwidth – broadband connection, speed, and stability. So, if the connection goes down and data packets won’t be transmitted quickly enough, there could be unpleasant delays during real-time calls. No steady Internet means catastrophic consequences for your business. Bad VoIP experience? Equals the loss of users.

  • Emergency Calls

Unfortunately, VoIP can’t properly handle 911 calls and the providers aren’t obligated to offer this service. The technology doesn’t allow location identification through a phone number or cell tower, so the Emergency system can’t define to which local dispatch center it should connect the caller. But many development companies are successfully trying to provide 911 calls in their apps, so it’s better for you to make an effort too.

  • Security Issues

Well, sure, security is the primary concern when it comes to any Internet technology. It’s not a secret that many VoIP providers suffered from security vulnerabilities reports. It happens because VoIP is a cloud-based and those data packets are being processed by numerous routers and various servers. So you’re going to need extra security measures and encryption mechanisms which will lead to extra spendings.

The most common security issues with Voice over IP are:

  1. Identity and service theft
  2. Viruses and Malware
  3. Denial of service and spam
  4. Intercepted calls (eavesdropping) and phishing attacks


The list above is just approximate, so you better learn the subject before you make your application. Also, to help you with the development process, we have a nice guide on how to make a mobile application in 7 easy steps.

In case you want to accomplish everything yourself, there are source code examples for you from both VoIP Android Development and iOS as well. There are various ready tutorials for you if you decide to try and dive into this field of building an IP-based application for voice and video conferences.

Anyway, if you have more questions, go ahead and shoot us a message! We’re here at your service and will be glad to review your VoIP project.  

Simple VOIP Mobile App by Tecsynt Solutions

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