Trying to describe in the simplest way the difference betwee

Question

Trying to describe in the simplest way the difference between KMP Flutter and ReactNative

jw · Answer

This is an apples to oranges comparison as it stands KMP is about taking code and compiling it to the native language execution binary of multiple platforms Flutter and React Native are frameworks for building cross platform applications Nothing about KMP has to do with UI for example You are free to target native UI or to write your own toolkit e g Compose ~Also React Native targets native UI widgets on every platform~ I guess you re implying you write against an abstraction I see below it shows native toolkit use A direct comparison would be KMP to Dart AOT compilation to native code which runs on multiple platforms and Javascript which can be run in a VM on every platform But KMP is not a framework it s a technology To compete with Flutter and React Native you have to drag in numerous libraries but selecting those libraries is up to you and you get to pick which values you want from them Maybe you want to target native UI you can Maybe you want to write one run everywhere and ship a UI toolkit you can

jw · Answer

If i had to illustrate the difference between these three I would say that Flutter and React Native are extremely opinionated frameworks for building cross platform solutions with little to no flexibility in the technology choices KMP is the exact opposite It s a means for targeting multiple platforms and then choosing what you want to run It s a recipe for competing with Flutter and React Native but it is not a baked cake You are on the hook for many choices How do you do persistence on each platform How do you talk to the UI How do you talk to the network How do you embed the multiplatform code into a larger platform specific app All of these have multiple options and you are responsible for not only choosing which one you want for each but also the integration between them all Flutter and React Native are pre made cakes Don t like the frosting they chose Too bad Don t like the batter Too bad KMP is a cake recipe Don t want chocolate frosting Switch it out Want to add sprinkles to the batter Go for it

Daniele B · Answer

Jake you are technically right But when talking about shared code options the main 3 choices are named as KMP Flutter ReactNative They are not exactly the same thing but when you talk about KMP you imply that you are going to use platform native UI toolkits That s the assumption My attempt is to summarize the 3 options in one slide which as you can see it s already quite full

Javier · Answer

When Compose targets iOS a lot of people will use it instead of Swift UI too

Javier · Answer

And the same for webs instead of using React for example

jw · Answer

Yep And you don t even need Compose We ve experimented with an abstract Canvas API into shared code for common widgets

jw · Answer

Anyway I ve made my point I think the slide is wildly misleading and pigeonholes KMP Frankly in a direct comparison KMP loses badly because it s so much extra work to compete on that platform Its greatest advantage and why you should use it is because it s not competing directly

Daniele B · Answer

< Javier> if you don t want flexibility in terms of UI there is already an established option and that is Flutter No need to wait for Compose being ported to iOS

dazza5000 · Answer

JW makes good points but i always view these slides as more appropriate for managers people less familiar with the intricacies

dazza5000 · Answer

KMP is so much more flexible than rn flutter because you can target native platforms and plugin to standard build tooling

Daniele B · Answer

The greatest advantage of KMP in my opinion is to be able to organize your project in a way that UI and business logic are fully decoupled That provides you with the great flexibility to target any kind of device in the future With Flutter and ReactNative that opportunity is lost

jw · Answer

But the reason you can do that is because KMP doesn t care You could just as easily have shared UI and platform specific business logic Kotlin does prescribe what you share and what you don t Doing it the way you describe is merely a pattern

Daniele B · Answer

As I said I am implying like 99 of the people I guess that with KMP the UI layer is not part of the share code That is the kind of KMP I mean in that slide

jw · Answer

If you re presenting to managers don t forget to put KMP is ~3x the effort for 1 3rd the result It s a choice that only makes sense if you value the technical aspect that differentiates it

jw · Answer

Sure that s fine But it s not intrinsic to KMP It s merely one variation of a configuration of disparate things which leverage KMP

Daniele B · Answer

Jake these are not the number I am experiencing At all If you are using Compose and SwiftUI you can easily share 85 of the code with KMP

jw · Answer

If you use Flutter you can share closer to 95 which less effort

Daniele B · Answer

yes surely but then you are stuck for ever

Daniele B · Answer

what about if you want to design a TV app using the same ViewModel and Data Layer

jw · Answer

Yep and you ve just illustrated why being precise about the technical underpinnings is important when comparing them

dazza5000 · Answer

There are also advantages like being able to share a common model across back and front that fluttrt and rn struggle with

Daniele B · Answer

With Flutter you can t With KMP you just need an extra 15 probably less

jw · Answer

You are making my point for me now

jw · Answer

These details are important when comparing

Daniele B · Answer

Jake that was not meant to be a deep comparison But just a simple summary in 1 slide

Daniele B · Answer

not sure how much more you can say in 1 slide

jw · Answer

Yeah and that s my issue It s misleading Compare KMP to Dart and JS Compare one KMP setup to Flutter and React Native It s all apples

Daniele B · Answer

I will start using the D KMP acronym more With D KMP I mean KMP with Declarative UIs and that s a setup

Daniele B · Answer

I wrote an article about what I call the D KMP architecture which is based on 3 pillars Declarative UIs Compose SwiftUI KMP MVI pattern

Javier · Answer

< Daniele B> Compose really give you the flexibility to do whatever you want It depends if the things you want to do but if you want you should be able to get a UI that matches with SwiftUI 1 1 With flutter too Other thing is if you want to spend the time to create all these components if the framework doesn t give them by default

Daniele B · Answer

< jw> concerning that I actually would have a question to ask you as yesterday you were saying you have been working with KMP and unidirectional data flow for a while now All articles I found talking about MVI with Kotlin are actually just referring to Android and not to MultiPlatform and all of them use SealedClassed for Intents But on iOS you cannot really use SealedClasses I wonder why not just using for intents simple functions which can easily be translated in any language and any platform defined on the shared ViewModel instead of SealedClasses Then if you want to implement any backpressure strategy on a specific intent function you just do it locally to such events intents in the shared code

Javier · Answer

Maybe Workflow by Square

jw · Answer

I don t do iOS All my stuff is Android JVM or JS

jw · Answer

And it s all 100 Kotlin I never write JS TS or Java

Daniele B · Answer

I guess you are using Kotlin React for the Web UI part

jw · Answer

No Don t like React at all I usually just hand write the binding to the DOM or extension APIs like Omnibox I would use Vue if I turned to a framework until Compose can compile to Kotlin JS and I can write DOM bindings

Daniele B · Answer

Yes definitely looking forward to Compose for Kotlin JS too It s going to be a game changer for the Web And after that Compose for WASM shouldn t be too late

Javier · Answer

< jw> is it planned to move Workflow Kotlin to Multiplatform And the Compose artifact so get support for JB compose

jw · Answer

I have never used Workflow I know nothing about it

rocketraman · Answer

KMM would be a better heading for the column than KMP That is the explicit architecture shown on the KMM home page <https kotlinlang org lp mobile >

rocketraman · Answer

Personally with the change to KMM I like the slide and find it quite clarifying The fact that KMM is a technology and not a framework is an important distinction though Its not a magic bullet You could add a row in the middle for Framework with the values Unopinionated bring your own mix and match and Opinionated prebuilt components for Flutter and React or something like that

kpgalligan · Answer

Just saw this thread Started a long reply but it s too late in the day for that kind of thing KMP and the other things are just wildly different I generally try to shut down comparisons but I get the urge I am curious who the audience would be Technically curious people OK Management I d go right into adoption risk if you were pushing KMM P vs the other two F amp RN are what we call Big Decisions They re hard to mix with native or walk back if things don t go well It s a long long topic though

Daniele B · Answer

I am summarizing the points here

jw · Answer

Are you talking about KMM or still KMP

kpgalligan · Answer

Who s the audience

Daniele B · Answer

< jw> I am referring to KMP even though I am aware that Kotlin JS won t become fully attractive until the new IR backend becomes stable and Compose for Web is released < kpgalligan> I would say the audience would be anyone who takes part in assessing a new technology CTOs and senior developers

jw · Answer

Ok then I still take issue with this messaging Especially now it s basically lying as if this configuration is the sole one

Daniele B · Answer

well I am referring to what I call D KMP DeclarativeUIs + KMP + MVI

Daniele B · Answer

I took your suggestion to just compare apples so I also updated the previous diagram

Daniele B · Answer

I am preparing the slides for DroidCon APAC where I will be talking for the first time about this D KMP architecture

Giorgos Neokleous · Answer

gt Business logic and UI are fully decoupled gt KMP enforces the boundaries but it doesn t offer that Those boundaries can be enforce in any project without bringing KMP into play The decoupling can be blurry now with JB and Jetpack Compose and still use KMP then the business logic might end up coupled with UI if not careful

Daniele B · Answer

< Giorgos Neokleous> to be clear once again I am talking about a specific setup of KMP called D KMP and not about KMP in general As we discussed earlier KMP on its own can be anything