Jetpack-Compose-Playground: a sample-code library for Compose, not an online playground

What Jetpack-Compose-Playground solves, and who it is actually for

Compose APIs are numerous and their parameters are not self-explanatory. A developer who needs a ModalBottomSheetLayout or a SubComposeLayout usually wants a short, complete Kotlin file they can read, copy and run, not a reference page that lists signatures without context. This repository is that file collection. The README describes it as a project where the author is "collecting a bunch of sample codes for Jetpack Compose", and the samples live in one Android app module rather than in separate repositories.

The audience is narrow and identifiable. It is Android developers who already have Android Studio, a JDK and the Android SDK, and who want to see how a specific composable is wired. Beginners get a Hello World page and a Compose for Android Developers page. People who prefer video get a Talks table with links such as Thinking in Compose. Nobody gets a hosted editor, and nobody gets a Gradle artifact to depend on. The unit of delivery is a cloned repository and a running app.

How the samples, docs and app module fit together

The repository has two parallel surfaces. The first is the Android app under the app directory, whose sample sources sit in app/src/main/java/de/jensklingenberg/jetpackcomposeplayground/mysamples/github. The second is the documentation site, built with MkDocs (mkdocs.yml is at the repository root) and published at foso.github.io/compose. The README points to both and treats them as interchangeable entry points: "Look in the repo ... or take a look at the GitHub page".

That split is the main architectural decision, and it has consequences. The docs site is organized by topic (Animation, Layouts, Foundation, Material, Cookbook), so a reader can find Crossfade or BadgeBox by name. The app module is organized as a single Kotlin project, so a reader can run the whole set at once. Keeping them separate means a doc page and its sample file can drift apart without any build step failing. Nothing in the repository describes a test that compares a documentation snippet against the compiled sample. Treat the app as the source of truth and the page as commentary.

The README also lists a Project Structure section with exactly one entry, /app, described as the Android project directory. There is no published library module, no Maven coordinate, and no API surface to import. The version badges in the README name Kotlin 2.0.20 and Compose 1.7.0, which is what the samples were written against.

Getting the repository and finding a first sample

There is no package to install. The README gives no install command, no Gradle dependency line and no published artifact; the project is consumed by cloning the repository and opening the app module. The repository root contains gradlew, gradlew.bat, settings.gradle.kts and build.gradle.kts, so the Gradle wrapper is the entry point once the clone is local.

The README's own route to a first sample is the app sources:

git clone https://github.com/Foso/Jetpack-Compose-Playground.git

After cloning, the README directs readers to the samples path in the repository:

app/src/main/java/de/jensklingenberg/jetpackcomposeplayground/mysamples/github

Open the cloned directory in Android Studio, let Gradle sync, and run the app configuration. The README does not document a minimum Android Studio version, a required JDK, or what to do if the sync fails, so those are the points where you are on your own. For a lighter first step, the README points to Hello World Compose and Compose for Android Developers on the published site.

What it is not: no browser editor, no online compiler

The word playground invites a wrong expectation. Jetpack-Compose-Playground does not compile Kotlin in a browser, does not render Compose in a web page, and does not give you an editable canvas. The homepage at foso.github.io/compose is a MkDocs site: text, code snippets and screenshots. Every example requires a local Android toolchain to actually execute.

That is a real limitation for the use case people often arrive with. If you want to paste a composable and see it render in seconds, this repository cannot do it, and the README does not claim otherwise. The screenshots in the README, such as DemoActivity.png and circprog.png, are static images of the sample app, not a live preview.

The second limitation is coverage. The README's index is broad but not exhaustive: it lists Crossfade under Animation, a set of layout and foundation composables, and a sizable Material list, plus a Cookbook with an overview page and a TextField changes page. A composable that is not on that list has no page here. The docs are a curated subset of the Compose API, and the README does not describe a process for requesting additions beyond the generic PR welcome badge.

How it compares with the official Compose sample repositories

The closest alternative is the official Android sample code, for example the Now in Android or JetSnack style apps that Google maintains. The difference in approach is scope versus integration. Official samples demonstrate a complete, opinionated application: navigation, data layer, dependency injection and UI wired together, which is what you want when the question is "how should a production Compose app be structured". This repository inverts that. It isolates one composable per sample so the reader can see a single API in a small file, which is what you want when the question is "what does this parameter do".

A second alternative is the Compose API reference itself. It is authoritative and always current, but it shows signatures and short snippets without a runnable project around them. Here you get the runnable project and a looser guarantee of currency.

The trade-off is maintenance. An official sample repository is tied to a release train. This one is community-driven, with a PR welcome badge and a Hacktoberfest topic, and its most recent release listed is v1.7.0 from 2024-09-07, while the last push to the repository was on 2026-03-31. The README badges name Compose 1.7.0, so any API that changed after that version may not be reflected.

Licence, maintenance and the cost of keeping it current

The repository is MIT licensed, with the LICENSE file at the root and an MIT badge in the README. For copying a snippet into your own project, MIT is permissive, but the usual caveat applies: the file carries no warranty, and you are responsible for checking that the code you lift is correct for your Compose version. None of this is legal advice.

Upgrade cost is the practical concern. Because the samples are pinned to Kotlin 2.0.20 and Compose 1.7.0 in the README badges, a reader on a later Compose release may find that a sample no longer compiles, particularly for APIs that were experimental or have since changed shape. The repository does not document a compatibility matrix, a changelog per sample, or a deprecation policy. The releases that exist (v1.7.0, v1.5.0, v1.4.3) are version bumps rather than per-sample migrations.

If you fork it for your own team, the maintenance work is real: you own the Gradle and Compose version bumps, and you own keeping the MkDocs pages aligned with the app sources, since nothing in the repository enforces that alignment.

Editorial conclusion

Adopt it if you learn Compose by reading and running working Kotlin, and you are willing to clone the repository and build the app module in Android Studio. Skip it if you want a browser editor, a Compose compiler in the cloud, or a maintained dependency you can pin in Gradle. Before you rely on it, open the specific page for the composable you care about, check whether its snippet still matches Compose 1.7.0, and confirm the source file under app/src/main/java/de/jensklingenberg/jetpackcomposeplayground/mysamples/github still compiles against your own Compose version.

Frequently asked questions

Official sources

1. Foso/Jetpack-Compose-Playground on GitHub
2. License: MIT
3. Project website
4. README
5. Releases