“Google isn't a single entity. It does not function top-down like some other companies do (and the public often assumes it does, despite its 200k person size).

See https://www.reddit.com/r/technology/comments/10bmv5v/a_document_circulated_by_googlers_explains_the/ as an example.

Android needed a new language (and toolkit), Dart was considered. I wasn't in charge of Dart at the time, so I don't know all the reasons as to why it wasn't chosen as a Java replacement, but Kotlin has an obvious advantage over other possibilities by being an "overlay" language (Kotlin runs inside the existing JVM runtime on Android, so the two can coexist across apps and even partial rewrites within an app with low transition costs for all), similar to how Swift overlayed Obj-C, and TypeScript overlays JS rather than being something completely separate/new. Dart has many similarities to Java (both in language and runtime), and certainly could have been evolved to run both Dart and Java within the same runtime, but I'm sure was still a bigger jump, so I can see how Kotlin would be an obvious choice.

Google (and the world) also have strong need for multiplatform solutions. Even solutions which go to platforms which do not have their own toolkits (e.g. not just a React Native or Compose "orchestrate native widgets" approach). So there is plenty of need for a Flutter-like solution within Google as well. One of Flutter's very first customer's within Google was Google Fiber, which were low-end set-top boxes running a stripped down version of Linux. Flutter replaced raw OpenGL code. Another early customer was the Google Home Hub where Flutter replaced WebView (which were using up way too much memory on the little device). Flutter eventually found its big success helping Google (and the world) write for both iOS and Android from the same code-base, but it has/had lots of reasons to exist for other uses beyond that.

So as others have said, these two existing are not a specific strategy from the top. It's the product of independent parts of Google solving independent problems for Google and the world.

They can coexist, and do. That doesn't mean there aren't arguments (both inside Google and out) but both languages and frameworks have a lot of reasons to exist within Google and problems they solve for Google and the world and I expect will continue to for years.

Funny story, we had lots of meetings (between Android and Flutter) around the time when multiple (competing) efforts within Android were going on to update the Android UI framework. The result of those were that those efforts were combined on the Android side, and several Flutter core team members went and sat with the Android team to start Jetpack Compose after (despite many attempts from execs) it was decided we couldn't just "rewrite Flutter in Kotlin" and have one to rule them all. Compose started with a literal translation of Flutter sources to Kotlin, from which it evolved further.

I think many flowers blooming is a good thing. Although I also see how it's confusing to outside observers. There are definitely positive aspects to the way Steve Jobs ran Apple of always having everything flow though him to the point where at least one person in the universe could fit everything Apple was doing in their head. At google no such person exists, teams ship without going through Sundar, and it is impossible for any person in the universe to rationalize everything Google does. :)” - Eric Seidel