How do I display a QR code in Jetpack Compose?

Generate a Bitmap using ZXing, convert it to an ImageBitmap, then display it with Image(bitmap = qrBitmap.asImageBitmap()). Wrap it in a composable function for reuse.

Can I scan QR codes with ZXing in Kotlin?

Yes. Use the zxing-android-embedded library for camera-based scanning. It provides an IntentIntegrator for easy integration and supports both Activity and Fragment scanning.

Does ZXing work with Kotlin Multiplatform?

ZXing is JVM-only. For Kotlin Multiplatform projects, use the QRCode.fun API via Ktor client, which works across all platforms (Android, iOS, desktop, web).

How do I customize QR code colors in Kotlin?

Generate the BitMatrix with ZXing, then create a Bitmap by iterating over the matrix and setting pixel colors. For advanced styling with logos and shapes, use the QRCode.fun API.

Kotlin QR Code Library

Generate QR Codes with Kotlin

Kotlin developers can use ZXing for Android QR code generation and scanning. Works seamlessly with Jetpack Compose and traditional Android Views.

Try QR Generator View API Docs

Installation

Add ZXing to your Android project using Gradle.

Gradle (Android)

implementation("com.google.zxing:core:3.5.3")

Gradle (with image)

implementation("com.google.zxing:core:3.5.3")
implementation("com.google.zxing:javase:3.5.3")

Generate QR Codes with Kotlin & ZXing

Code examples using ZXing in Kotlin for Android.

Generate QR Code Bitmap (Android)

import android.graphics.Bitmap
import com.google.zxing.BarcodeFormat
import com.google.zxing.MultiFormatWriter

fun generateQRCode(data: String, size: Int = 300): Bitmap {
    val matrix = MultiFormatWriter().encode(
        data, BarcodeFormat.QR_CODE, size, size
    )

    return Bitmap.createBitmap(size, size, Bitmap.Config.RGB_565).apply {
        for (x in 0 until size) {
            for (y in 0 until size) {
                setPixel(x, y, if (matrix[x, y]) 0xFF1A2B3C.toInt() else 0xFFFFFFFF.toInt())
            }
        }
    }
}

// Usage
val qrBitmap = generateQRCode("https://qrcode.fun")

Jetpack Compose QR Code

@Composable
fun QRCodeImage(
    data: String,
    modifier: Modifier = Modifier,
    size: Int = 300
) {
    val bitmap = remember(data) { generateQRCode(data, size) }

    Image(
        bitmap = bitmap.asImageBitmap(),
        contentDescription = "QR Code",
        modifier = modifier.size(200.dp)
    )
}

// Usage in a Composable
@Composable
fun MyScreen() {
    QRCodeImage(data = "https://qrcode.fun")
}

QRCode.fun API

Generate QR Codes via API in Kotlin

Call the QRCode.fun API from Kotlin using OkHttp or Ktor for styled QR codes.

Kotlin API Integration

import okhttp3.*
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.RequestBody.Companion.toRequestBody
import org.json.JSONObject

suspend fun generateQRCodeViaAPI(data: String): String {
    val client = OkHttpClient()
    val json = JSONObject().apply {
        put("data", data)
        put("width", 300)
        put("height", 300)
        put("type", "png")
        put("margin", 10)
        put("dotsOptions", JSONObject().apply {
            put("color", "#1A2B3C")
            put("type", "rounded")
        })
        put("cornersSquareOptions", JSONObject().apply {
            put("color", "#8564C3")
            put("type", "extra-rounded")
        })
        put("backgroundOptions", JSONObject().apply {
            put("color", "#FFFFFF")
        })
    }

    val request = Request.Builder()
        .url("https://qrcode.fun/api/generate-qr-styled")
        .post(json.toString().toRequestBody("application/json".toMediaType()))
        .build()

    val response = client.newCall(request).execute()
    val result = JSONObject(response.body?.string() ?: "")
    return result.getString("data") // base64 PNG data URL
}

Live QR Code Preview

Try generating a QR code with Kotlin right now.

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QR preview

ZXing vs API

Compare using ZXing in Kotlin versus the QRCode.fun API.

Feature	ZXing Library	QRCode.fun API
Setup complexity	Gradle dependency + Bitmap rendering	Single HTTP request via OkHttp
Customization	Size, error correction, colors via Bitmap	Full styling: colors, shapes, logos
Offline support	Yes	Requires internet
Maintenance	Gradle dependency update	Always up-to-date
Output formats	Bitmap (Android)	PNG, SVG

Kotlin QR Code Use Cases

Common scenarios for QR codes in Kotlin applications.

Android Apps

Generate and display QR codes in Android apps for sharing links, contacts, Wi-Fi credentials, and payment information.

Jetpack Compose

Create composable QR code components with custom styling and animations for modern Android UIs.

Kotlin Multiplatform

Share QR code generation logic across Android, iOS, and desktop using Kotlin Multiplatform with the QRCode.fun API.

Backend Services

Generate QR codes in Ktor or Spring Boot Kotlin services for tickets, invoices, and authentication flows.

Frequently Asked Questions

Common questions about generating QR codes with Kotlin.

For Android, ZXing (zxing:core) is the standard choice. For Kotlin Multiplatform or server-side, consider using the QRCode.fun API for consistency across platforms.

Start generating QR codes with Kotlin

Use our free generator or integrate the API into your Kotlin and Android applications.

Open QR Generator Explore API Docs