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Should my company choose RubyMotion or Swift?

Posted in Inside TFG, iOS, RubyMotion, Swift

One of the most highly debated topics at The Frontier Group over the last two years has been whether to use RubyMotion or Objective C for iOS development.

There were a tremendous amount of reasons for and against both RubyMotion and Objective C. In the end we settled on RubyMotion, reasoning that we could learn Cocoa Touch and iOS faster using Ruby than Objective-C. In hindsight, I think it was the correct decision. If you are a Ruby on Rails developer looking to make the jump to iOS, RubyMotion is a great place to start, even if you want to move to Swift later.

When Swift was announced I was intrigued. To me, Swift looked like Ruby and C# had a beautiful strongly-typed baby. Swift’s improved syntax was the push I needed to vote in favour of moving from RubyMotion.

At this point the great debate came to an end. After two awesome years with RubyMotion, The Frontier Group decided to become a Swift shop. I will outline the main factors we considered in this post. Hopefully they can assist you in your decision making process.

A note about RubyMotion

RubyMotion is production ready and extremely enjoyable to use in development of iOS applications.

I want to make something abundantly clear. RubyMotion is awesome. I have launched many apps using RubyMotion. Despite what you may have read RubyMotion is 100% production ready. You can integrate RubyMotion with Interface Builder, CoreData, and every Cocoa Touch SDK easily. RubyMotion is not some hacky workaround, it is a native solution. Apps made in RubyMotion are just as fast and responsive as their Objective-C and Swift counterparts. 

In RubyMotion I’ve successfully used many frameworks in Cocoa Touch. From custom drawing and animation, to Facebook, Twitter, maps, location services, music players, the camera and more. There is the occasional bug, but I’m yet to find one that can’t be worked around trivially.

RubyMotion has improvements and updates released every couple of months. A majority of the updates include impressive improvements to the speed of compile time and commonly used functions. I believe the latest update (2.32) reduced compile time by 40%. 

One thing you should understand – making good iOS apps is more about understanding how the user will interact with the app than it is writing code. It doesn’t matter whether you use RubyMotion or Swift if you can’t provide a good user experience.

The majority of the coding of an iOS app (I’d say 90%) is about understanding how the SDK works. So if you “master” RubyMotion over the course of a couple of years, by virtue of my previous statement you would have had to “master” Cocoa Touch. So 90% of your work is already done if you need to move over to Swift. You would just have to learn a little bit about Swift and get in the mindset of writing in a typed language.

When moving from RubyMotion to Swift I would estimate it took me two weeks to get back to full productivity. The learning curve moving to Swift was minimal, even for someone who hadn’t coded professionally in a strongly typed language. Due to my level of experience with Cocoa Touch I could get into the swing of things easily. 

So…if RubyMotion is so great, why is TFG moving away from it? Let’s have a look.

RubyMotion or Swift?

There were a couple of points that always came up when discussing whether TFG would be a RubyMotion or Swift/Objective C shop. Here’s a verbose run through of each, if you don’t have time to do heavy reading, skip to the bottom for a summary.

Learning a new language: Weakly Typed vs Strongly Typed

Your company needs to think about how the learning curve of moving to a typed language will affect your bottom line if none of your developers have experience with typed languages.

RubyMotion: At TFG, we had a high level of experience with Ruby via Ruby on Rails. So there was no time spent learning new syntax for RubyMotion. I knew all the string and array functions in Ruby, how to declare functions, and how to do sneaky things with blocks. When I started RubyMotion, I only had to learn a new framework (Cocoa Touch), rather than learning a new language (Swift), framework (Cocoa Touch), and bloated toolset (Xcode). That had a huge positive impact on my delivery time and app quality.

Swift: Moving to a strongly typed language like Swift would require some acclimation for our developers. It would open us up to lots of time spent thrashing around trying to solve basic syntax problems.

At first it felt like my hands were tied behind my back because I didn’t know how to do basic things. With Swift being a new language there isn’t the wealth of stack overflow and other posts with solutions to basic problems. I had to solve a lot of problems myself via trial and error and beta level compiler error messages. So our concerns that learning a new language would be costly were definitely warranted. There will always be teething issues when learning new languages – this is not unique to Swift.

However, if you are coming from a company with lots of experience with a typed language then you may have an easier time picking up Swift than RubyMotion. It really depends on your company’s background.

Development Environment: Xcode vs command line and text editor

Your company needs to bear in mind how its developers like to work. If nobody likes the type of environment provided by RubyMotion, they’ll hate working with it and productivity and morale will drop. On the other hand, if your developers hate using IDEs then they may prefer not to use Xcode’s development environment and may not like the idea of moving to Swift.

RubyMotion: RubyMotion apps can be completely built with just your favourite text editor and a Bash prompt. You do not need to interact with the Xcode UI directly at any stage if you don’t want to. I mentioned above you can use the IB gem to use Interface Builder if you want. I would recommend looking into it. Implementing autolayout is trivial using IB, and a serious pain to write manually with code. Although there are libraries that attempt to work around it. like MotionKit (teacup’s progeny) and the much older motion-layout.

Swift: You can use Swift without having to rely on Xcode as your primary editor.

If you don’t use storyboards or xibs, you don’t need to use Interface Builder. Interfaces can be built entirely in code. However, the API for manually writing autolayout constraints is laborious. Interface Builder does a fantastic job of implementing autolayout and it is a breeze to use after the initial learning curve.

The crux of the matter is that an aversion to using Xcode should not prevent you from looking into Swift. However, I think any iOS developer would be well served by becoming proficient in using Xcode.

Xcode is likely where you will end up if you choose Swift development. Make sure that your development team can get on board with that.

Some other things you should look at when determining how your team will enjoy the development environment:

  • Syntax of the language. Objective C was a no-go for me. Swift has a much more readable syntax. RubyMotion is even better (I love you, Ruby).
  • Availability of 3rd party plugins. RubyMotion has access to some Ruby gems AND all the Cocoapods via motion-cocoapods, Swift has access to Cocoapods).
  • Testing frameworks available. RubyMotion has MacBacon which is a fairly stripped down RSpec clone for unit testing. You have access to tools like motion-calabash for interface testing. Look at the last updated dates for those libraries, they are old and dusty. I’m not up to speed on the pimpest testing available in Swift and Xcode, so I’ll leave that topic for now. You will need to do your own research and make your own judgements. 

Development Environment: Instruments Support

RubyMotion doesn’t have the same support for Instruments that Swift does.

When I was tracking down memory leaks in RubyMotion apps I had to do it manually. The only Instruments that I could use were for checking total app memory and CPU usage. That and a combination of handily places puts statements in dealloc calls were what allowed me to solve all the memory issues I had in the cornucopia of RubyMotion apps I worked on.

If you really love tools like Instruments, Swift will win hands down. However, if you’re a “get your hands dirty” type like me, there are other ways to resolve your issues.

Development Environment: Debugging

Stack traces from RubyMotion can be pretty damn useless

I have nothing to say in favour of the stack traces RubyMotion provides. Sometimes you get a stack trace, sometimes you don’t. I’m guessing depending on which thread the process was running. When you do, sometimes the stack trace appears to be pointing to re-allocated memory and no longer has any useful information for you.

If you rely on stack traces for your debugging, RubyMotion is inferior to Swift. It never stopped me from fixing bugs, but I’m a fairly experienced developer. I think newbie devs will have a really hard time debugging RubyMotion apps. You have to know where to look for bugs.

Don’t get me wrong, for any memory issue in either language you’re going to have a hard time in the beginning.

Development Environment: REPL vs ‘REPL’

The REPL in RubyMotion allows you full access to your app – you can change views, update CoreData instances, test your classes out, and check instance variable values. The REPL in Swift is nowhere near as powerful at the moment.

RubyMotion: If you’re like me and you love to make live changes to your app to test out how font sizes will look or add data on the fly, you’re going to want to use RubyMotion.

Swift: The REPL in Swift is almost pointless to me. There were some interesting demos in the WWDC talk, but I have not been able to make it do anything useful. 


RubyMotion has less conferences, user groups, and developers than Swift. Swift’s community will grow faster than RubyMotion’s.

RubyMotion: RubyMotion is relatively young, and still pretty niche. Early on we saw some big hitters like the BaseCamp app embrace RubyMotion, but RubyMotion really hasn’t become mainstream. As a result, the amount of media related to RubyMotion is quite small. One thing to keep in mind is that it will be much harder to replace RubyMotion developers than it would be to replace Swift developers (who will shortly be a dime a dozen). This could also affect things like salary, but I don’t really want to go down the supply and demand path.

Want to have a look at some of the community sources for RubyMotion? Check their official blog and the google group. You could also join the /r/rubymotion subreddit, sign up to the RubyMotion dispatch or MotionInMotion. If you’re new to RubyMotion, you should read Clay Allsop’s RubyMotion Tutorial. 

If conferences are your thing, keep an eye out for #inspect next year, as it has already come and gone for 2014.

Another note on community – RubyMotion belongs to the Ruby community. I’ve seen RubyMotion talks popping up at Ruby conferences as well, like Laurent Sansonetti doing a talk at Ruby Kaigi 2014.

Swift: Although Swift is even younger than Rubymotion, it is the new in vogue programming language for iOS and Apple approved. I think it’s a safe assumption to make that over the next couple of years Objective C developers will be making the move to Swift. There will be a lot more user groups, meetups, and conferences aimed exclusively at Swift developers than there will ever be for RubyMotion.

Apple have an official Swift blog that is updated every couple of weeks so far. As Swift is very new I can’t really point to any great sources of information yet. There are plenty out there, I just haven’t had the time to comb through them and sort the good from the bad.

If you want to talk conferences, you aren’t going to get much bigger than WWDC – follow this link to see all the talks from 2014. Lots of Swift content there.

On the other hand: There are tonnes of resources regarding iOS development that cater for both RubyMotion and Swift developers. The iOS Dev Weekly is a great newsletter to subscribe to, for example. RubyMotion developers can also learn a lot from WWDC talks about Cocoa Touch specific topics. Although they’ll have to convert the code samples from Swift.

Regarding hiring Swift and RubyMotion devs…TFG has hired Objective C developers before to work on RubyMotion projects. It didn’t go well. Developers can often be dogmatic, and I think you’ll find that some people beat the “one true language” drum a little too hard. Depending on where you live, you might not be able to find any local RubyMotion developers. If you only have one developer on RubyMotion, consider whether you can afford to have your bus factor that low.

One very important thing to keep in mind regarding community size is the number of open source contributors. Rails developers are used to standing on the backs of giants. Rails itself is open source and constantly updating. We also rely on tonnes of other gems to build our apps as efficiently as possible (for example: devise for authentication).

In small communities these gems have less people to work on them. This means gems will be updated less frequently, and will have less feedback used to fix bugs and build improvements.


The Cocoa Touch documentation is written using Swift and Objective C samples.

All the code you’ll find in the extremely well written Apple docs is written using Swift and Objective C sample. If you’re writing Swift you can copy it into your code. In RubyMotion you will need to convert it into RubyMotion code first. This may not sound like a huge deal until you consider the how verbose some of the Cocoa Touch methods are and how often you’ll have to convert them.

This can be very difficult for RubyMotion beginners with little Cocoa Touch experience. It tripped up some of the developers at TFG early on.


RubyMotion Swift
Production ready? 100% 100%
Language Weakly Typed (variant of Ruby) Strongly Typed
Integration with Xcode and Interface Builder Good, thanks to the IB gem. Great, there’s still some missing functionality as of Xcode 6 GM (like the refactor function).
Integration with Instruments Poor, you can get basic system usage but not much more Great
Integration with Cocoa touch Good, some issues now and then Great
Debugging Average. It’s not terrible but finding memory leaks is a manual process without Instruments support Good. Stack traces are relevant. Memory issues can be tracked down using instruments
REPL Great Poor at the moment
Maintainers Small. There’s a tiny bus factor keeping RubyMotion (the toolchain) alive. If Laurent et al decide they no longer want to support RubyMotion you’re out of luck. Swift is supported by one of the wealthiest companies on the planet (Apple). After Apple adopted Objective C they proceeded to significantly upgrade it. It feels safe to assume that Swift will continuously get upgraded by Apple.
Community Small, but active Hard to say at the moment due to Swift’s recent release. If we assume it will be as big as Objective C’s – Large.
Conferences Few (#inspect being the primary, but Ruby conferences often contain RubyMotion talks) Many. WWDC has general Cocoa Touch information but primarily Swift focussed
Employment Opportunities Fewer Many
3rd party plugins Plenty of RubyMotion gems, access to CocoaPods via motion-cocoapods Access to CocoaPods
Stack Overflow posts Few for RubyMotion, lots for Objective C that need to be converted Few for Swift, lots for Objective C that need to be converted. This will change over time in favour of Swift.

Making a decision

At TFG, we looked at everything we knew about our company and developers and decided we wanted to move forward with Swift. Personally, I was very excited to learn a new language. I reasoned that knowing more languages would make me a better developer and benefit TFG. I think this has proven true in only a few short months.

There are pros and cons for both RubyMotion and Swift. As a company, you need to sit down and decide what’s important to you before moving forward with a decision. Neither choice is objectively better.

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