Is Kotlin or Swift vital for mobile developers?

The mobile market is evolving at warp speed and there’s much more to come over the next few years so if you're an Android or iOS developer you couldn’t be in a better position.  But are the latest languages quite as vital as developers or businesses think?  

The mobile app market statistics this year indicate huge increases from $188b in 2020 from $88.3b in 2016 and there are likely to be 3 billion smartphone users by 2021 whilst mobile apps and downloads are likely to pass the 300 billion mark at the end of this year (stats from Statistica)

New technology is driving much of this growth with

  • the AR/VR market expected to rise to $209.2b by 2022  
  • iOT, Blockchain, AI and chatbots all increasingly common place (Gartner predict that 85% of customer service interaction will be handled by chatbots by 2020)
  • over 4 million Accelerated Moble Pages (AMP) being published last year

Does the rise of these new technologies mean that you have to learn the latest languages to be considered for the best Android or iOS developer roles?  As a business - should you be using the latest techology to keep up to date in the marketplace?  

Do you really need the latest hot languages?

The most recent change in the Android and iOS app developer job market is the transition from Objective-C and Java to Swift and Kotlin. These new languages provide certain advantages such as less code, dynamic libraries and faster code performance but has also created new challenges for businesses and developers alike.

Developers are facing the reality that they need to evolve to stay relevant to future employers whilst businesses often feel they need to introduce new languages to stay competitive in the job market. This may not always be what is best for the business as a whole however, or what developers want or need for their career.

Will both developers and businesses fall behind if they do not introduce these newer languages into their work?

Android vs iOS

Most early startups have built their entire applications in Swift and more established businesses have begun to transition to Swift or have already done so. Therefore, most iOS roles require Swift alone or as well as Objective-C.

However, on the Android side Kotlin has only recently become popular. Many businesses now look for an experienced Kotlin developer to help them start to rewrite their applications, although many are still only looking for personal experience or an interest in using Kotlin, for when they decide to make the change.   

Industry Variations

Many industries suffer from a wide range of internal hindrances that prevent the switch to new and better languages.  For example, many businesses in the Cybersecurity industry cannot rewrite their code easily in the new languages without increasing the danger of introducing additional security holes when moving from legacy systems. They can continue to build new features in Swift or Kotlin; however, the developers will need to work with both legacy and new code. This can leave them at a disadvantage when looking to hire.

Many large and older well–respected companies are still using Objective-C. With a massive code-base, they will need to be highly incentivised to make the change to spend months to years changing something that is working acceptably.

Startups with a much newer and smaller code-base or a focus on greenfield projects are much more likely to use Swift or Kotlin as they face few legacy system restrictions. Consequently startup iOS and Android roles are often in high demand especially from more junior developers as they seem more exciting initially and developers don't risk being tied to an old language that may decrease in value soon.  Older businesses looking for juniors are starting to see the impact of the languages that they utilise and can struggle to persuade younger developers to divert their attention away from the funky exciting startups.  On the upside it can often be the case that the more senior developers are more happy to stay in their field of expertise in the larger companies.

Demand and Supply

So how much are Kotlin and Swift actually in demand in the UK?  Android have a huge market share of 76.61% worldwide now with iOS just 20.66% and this is clearly demonstrated in the decrease in iOS and Swift roles across both permanent and contract jobs in the UK below (stats taken from Itjobswatch).  Despite the decrease in iOS roles the pay rate remains fairly stable for both Contract and Perm and there doesn't appear to be an over supply of Swift developers in the market so it may still be a useful area to work in.  

The number of Android jobs in comparison, especially using Kotlin, are rising very fast.  The pay rates have come down over the last few years but this is likely due to more people entering the market with Kotlin skills now

nb.  Java is included below but doesn't cover just Android jobs

System Language Type        
        Last 6 Months 2017 2016
IOS Swift  Permanent  No. of jobs ↓ 222 ↓ 260 314

UK avg. pay




    Contract No. of jobs





UK daily pay




  Objective-C Permanent  No. of jobs

↓ 787

↓ 1054


      UK avg. pay




    Contract No. of jobs




      UK daily pay




Android Kotlin Permanent  No. of jobs




      UK avg. pay




    Contract No. of jobs




      UK daily pay




  Java Permanent  No. of jobs




      UK avg. pay




    Contract No. of jobs




      UK daily pay





Junior vs Senior

When looking for junior developers businesses can struggle if they don't offer the opportunity to work solely on new languages that are believed to be the future of mobile development. Companies who can't offer the newer languages must focus on the allure of Machine Learning, VR and AI or other innovative technologies to attract talent instead. The concern for these companies is that this might not be enough when competing with startups who can offer both.

On the other hand, many established companies who have not migrated to the new languages can provide amazing training and stability, which will always look good on a developers CV.

Views are more mixed when it comes to senior developers with many wanting to keep up with new technologies and looking specifically for roles using Kotlin or Swift but not always having the opportunity to move away from the older languages that they are familiar with.  

Do you really need Swift or Kotlin as an Android or iOS developer?

Swift and Kotlin have created a new era for mobile development and the impact on iOS and Android recruitment is becoming increasingly clear.  However, it is too early to tell the long-term benefits or implications of the new languages. Objective-C and Java will not be going anywhere anytime soon, but it would still be useful for developers and companies to integrate the new languages into their work, especially when looking for a new role or expanding the business.  Of course there are many other languages and skills that might be equally necessary for Android or iOS jobs such as C++, Python, Cordova, Xamarin, C, Ocaml, Xcode - we'll save those for another blog!

Written by Rachel Sur - Mobile Recruitment Specialist


No. of jobs

Added 17-Oct-2018