FileKit

Pick, save, read, and write files with one Kotlin Multiplatform API, using each platform’s native dialogs.

FileKit is the file layer for Kotlin Multiplatform. Open native file, photo, directory, and camera pickers, save and share files, and read or write them through a single PlatformFile type. The same code runs on Android, iOS, macOS, desktop JVM (Windows, macOS, Linux), Linux and Windows native, JS, and Wasm, and FileKit Core also runs on watchOS.

FileKit in 30 seconds

Let the user pick a photo, then show it or read its bytes.

Compose

@Composable
fun PhotoPicker() {
    val scope = rememberCoroutineScope()
    var photo by remember { mutableStateOf<ImageBitmap?>(null) }

    val launcher = rememberFilePickerLauncher(
        type = FileKitType.Image,
        onError = { failure -> println("Picker failed: ${failure.message}") },
    ) { file ->
        // null when the user cancels
        if (file != null) scope.launch { photo = file.toImageBitmap() }
    }

    Button(onClick = { launcher.launch() }) { Text("Pick a photo") }
    photo?.let { Image(bitmap = it, contentDescription = null) }
}

Try it in your browser

Run the FileKit sample app live, with no install.

Run it in two minutes

Add one dependency, do the per-platform setup, and pick your first file.

What you can build

Photo and file uploads

Open the native file picker or the Android and iOS photo picker, then read the bytes to upload them.

Export and save documents

Ask the user where to save a file, then write text, bytes, or a stream to it.

Work with project folders

Let users pick a folder, then list, walk, and copy its contents. Keep access across launches with bookmarks.

Camera capture and photo processing

Take a photo, compress or resize it, and save it to the user’s gallery.

Share and open files

Send a file to the system share sheet or open it in the default app.

Local app storage

Store files in the app’s files, cache, and databases directories. The same paths work with DataStore or Room.

Platforms

Android	iOS	macOS	JVM desktop	Linux native	Windows native	JS	Wasm	watchOS
✅	✅	✅	✅	✅	✅	✅	✅	Core only

Every target with filekit-dialogs uses the platform’s native dialogs (watchOS has FileKit Core only). Some features are platform-specific: the camera and share sheet are mobile-only, the file saver is not available in browsers, and Compose and Coil support follows Compose Multiplatform’s targets. See the platform support matrix for a feature-by-feature breakdown.

Modules

Add only the modules you need. Each module pulls in the ones it builds on.

Artifact	What it gives you	Add it when
filekit-core	PlatformFile, reading and writing, file system operations, app directories, image utilities, bookmarks	You work with files and don’t need dialogs
filekit-dialogs	Native file, gallery, directory, and camera pickers, plus the file saver, share, and open-file dialogs, as suspend functions	You open dialogs from shared code, ViewModels, or non-Compose UI
filekit-dialogs-compose	remember…Launcher APIs and PlatformFile.toImageBitmap()	Your UI uses Compose Multiplatform
filekit-coil	PlatformFile support in Coil 3 AsyncImage	You display images with Coil

Next steps

Quickstart

Pick and read your first file.

Installation

Dependencies and per-platform setup.

Platform support

See which features each platform supports.

Use FileKit with AI assistants

Give your coding assistant the FileKit docs through MCP, llms.txt, or Markdown.

Who uses FileKit

See how each project uses FileKit in the showcase, and read more on the wall of love.

Browse the sample apps to see FileKit running on each platform.