diff --git a/backup/src/jsMain/kotlin/com/wire/backup/dump/BackupExportResult.kt b/backup/src/jsMain/kotlin/com/wire/backup/dump/BackupExportResult.kt
index 018c3d18c0..c46e881ee2 100644
--- a/backup/src/jsMain/kotlin/com/wire/backup/dump/BackupExportResult.kt
+++ b/backup/src/jsMain/kotlin/com/wire/backup/dump/BackupExportResult.kt
@@ -17,9 +17,13 @@
  */
 package com.wire.backup.dump
 
+import org.khronos.webgl.Uint8Array
+
 @JsExport
 public sealed class BackupExportResult {
-    public class Success(public val bytes: ByteArray) : BackupExportResult()
+    public class Success(
+        public val bytes: Uint8Array
+    ) : BackupExportResult()
     public sealed class Failure(public val message: String) : BackupExportResult() {
         /**
          * Represents an I/O error that occurs during an export process.
diff --git a/backup/src/jsMain/kotlin/com/wire/backup/dump/MPBackupExporter.kt b/backup/src/jsMain/kotlin/com/wire/backup/dump/MPBackupExporter.kt
index 09cdddcead..f483fc5a10 100644
--- a/backup/src/jsMain/kotlin/com/wire/backup/dump/MPBackupExporter.kt
+++ b/backup/src/jsMain/kotlin/com/wire/backup/dump/MPBackupExporter.kt
@@ -72,7 +72,7 @@ public actual class MPBackupExporter(
         when (val result = finalize(password, output)) {
             is ExportResult.Failure.IOError -> BackupExportResult.Failure.IOError(result.message)
             is ExportResult.Failure.ZipError -> BackupExportResult.Failure.ZipError(result.message)
-            ExportResult.Success -> BackupExportResult.Success(output.readByteArray())
+            ExportResult.Success -> BackupExportResult.Success(output.readByteArray().toUByteArray().toUInt8Array())
         }
     }
 }
diff --git a/backup/src/jsMain/kotlin/com/wire/backup/ingest/MPBackupImporter.kt b/backup/src/jsMain/kotlin/com/wire/backup/ingest/MPBackupImporter.kt
index 6aff20ced1..ddf1a69635 100644
--- a/backup/src/jsMain/kotlin/com/wire/backup/ingest/MPBackupImporter.kt
+++ b/backup/src/jsMain/kotlin/com/wire/backup/ingest/MPBackupImporter.kt
@@ -42,15 +42,15 @@ import kotlin.js.Promise
 public actual class MPBackupImporter : CommonMPBackupImporter() {
     private val inMemoryUnencryptedBuffer = Buffer()
 
-    public fun peekFileData(data: ByteArray): Promise<BackupPeekResult> = GlobalScope.promise {
+    public fun peekFileData(data: Uint8Array): Promise<BackupPeekResult> = GlobalScope.promise {
         val buffer = Buffer()
-        buffer.write(data)
+        buffer.write(data.toUByteArray().toByteArray())
         peekBackup(buffer)
     }
 
-    public fun importFromFileData(data: ByteArray, passphrase: String?): Promise<BackupImportResult> = GlobalScope.promise {
+    public fun importFromFileData(data: Uint8Array, passphrase: String?): Promise<BackupImportResult> = GlobalScope.promise {
         val buffer = Buffer()
-        buffer.write(data)
+        buffer.write(data.toUByteArray().toByteArray())
         importBackup(buffer, passphrase)
     }
 
diff --git a/samples/src/jsMain/kotlin/samples/backup/BackupSamplesJs.kt b/samples/src/jsMain/kotlin/samples/backup/BackupSamplesJs.kt
index 420cef8884..0587fc2794 100644
--- a/samples/src/jsMain/kotlin/samples/backup/BackupSamplesJs.kt
+++ b/samples/src/jsMain/kotlin/samples/backup/BackupSamplesJs.kt
@@ -22,6 +22,7 @@ import com.wire.backup.ingest.BackupPeekResult
 import com.wire.backup.ingest.MPBackupImporter
 import com.wire.backup.ingest.isCreatedBySameUser
 import kotlinx.coroutines.await
+import org.khronos.webgl.Uint8Array
 
 object BackupSamplesJs : BackupSamples() {
 
@@ -51,7 +52,7 @@ object BackupSamplesJs : BackupSamples() {
         println("Backup created file. Raw binary data: $fileData")
     }
 
-    suspend fun peekBackup(data: ByteArray) {
+    suspend fun peekBackup(data: Uint8Array) {
         // Peek into backup file
         val importer = MPBackupImporter()