diff --git a/bytestring/api/kotlinx-io-bytestring.klib.api b/bytestring/api/kotlinx-io-bytestring.klib.api
index 7dd54088..47fe266b 100644
--- a/bytestring/api/kotlinx-io-bytestring.klib.api
+++ b/bytestring/api/kotlinx-io-bytestring.klib.api
@@ -82,3 +82,15 @@ final fun (kotlinx.io.bytestring/ByteStringBuilder).kotlinx.io.bytestring/append
 final fun <#A: kotlin.text/Appendable> (kotlin.io.encoding/Base64).kotlinx.io.bytestring/encodeToAppendable(kotlinx.io.bytestring/ByteString, #A, kotlin/Int = ..., kotlin/Int = ...): #A // kotlinx.io.bytestring/encodeToAppendable|encodeToAppendable@kotlin.io.encoding.Base64(kotlinx.io.bytestring.ByteString;0:0;kotlin.Int;kotlin.Int){0§<kotlin.text.Appendable>}[0]
 final fun kotlinx.io.bytestring/ByteString(kotlin/ByteArray...): kotlinx.io.bytestring/ByteString // kotlinx.io.bytestring/ByteString|ByteString(kotlin.ByteArray...){}[0]
 final inline fun kotlinx.io.bytestring/buildByteString(kotlin/Int = ..., kotlin/Function1<kotlinx.io.bytestring/ByteStringBuilder, kotlin/Unit>): kotlinx.io.bytestring/ByteString // kotlinx.io.bytestring/buildByteString|buildByteString(kotlin.Int;kotlin.Function1<kotlinx.io.bytestring.ByteStringBuilder,kotlin.Unit>){}[0]
+
+// Targets: [js, wasmJs]
+final fun (kotlinx.io.bytestring/ByteString).kotlinx.io.bytestring/toArrayBuffer(): org.khronos.webgl/ArrayBuffer // kotlinx.io.bytestring/toArrayBuffer|toArrayBuffer@kotlinx.io.bytestring.ByteString(){}[0]
+
+// Targets: [js, wasmJs]
+final fun (kotlinx.io.bytestring/ByteString).kotlinx.io.bytestring/toInt8Array(): org.khronos.webgl/Int8Array // kotlinx.io.bytestring/toInt8Array|toInt8Array@kotlinx.io.bytestring.ByteString(){}[0]
+
+// Targets: [js, wasmJs]
+final fun (org.khronos.webgl/ArrayBuffer).kotlinx.io.bytestring/toByteString(): kotlinx.io.bytestring/ByteString // kotlinx.io.bytestring/toByteString|toByteString@org.khronos.webgl.ArrayBuffer(){}[0]
+
+// Targets: [js, wasmJs]
+final fun (org.khronos.webgl/Int8Array).kotlinx.io.bytestring/toByteString(): kotlinx.io.bytestring/ByteString // kotlinx.io.bytestring/toByteString|toByteString@org.khronos.webgl.Int8Array(){}[0]
diff --git a/bytestring/js/src/ByteStringsJs.kt b/bytestring/js/src/ByteStringsJs.kt
new file mode 100644
index 00000000..7a0f3d30
--- /dev/null
+++ b/bytestring/js/src/ByteStringsJs.kt
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2017-2024 JetBrains s.r.o. and respective authors and developers.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENCE file.
+ */
+
+package kotlinx.io.bytestring
+
+import org.khronos.webgl.ArrayBuffer
+import org.khronos.webgl.Int8Array
+
+/**
+ * Returns a new [Int8Array] instance initialized with bytes copied from [this] ByteString.
+ */
+public fun ByteString.toInt8Array(): Int8Array = toByteArray().unsafeCast<Int8Array>()
+
+/**
+ * Returns a new [ArrayBuffer] instance initialized with bytes copied from [this] ByteString.
+ */
+public fun ByteString.toArrayBuffer(): ArrayBuffer = toInt8Array().buffer
+
+/**
+ * Return a new [ByteString] holding data copied from [this] Int8Array.
+ */
+public fun Int8Array.toByteString(): ByteString = ByteString(*unsafeCast<ByteArray>())
+
+/**
+ * Returns a new [ByteString] holding data copied from [this] ArrayBuffer
+ */
+public fun ArrayBuffer.toByteString(): ByteString = Int8Array(this).toByteString()
\ No newline at end of file
diff --git a/bytestring/js/test/ByteStringConversionsTest.kt b/bytestring/js/test/ByteStringConversionsTest.kt
new file mode 100644
index 00000000..ccd82ea7
--- /dev/null
+++ b/bytestring/js/test/ByteStringConversionsTest.kt
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2017-2024 JetBrains s.r.o. and respective authors and developers.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENCE file.
+ */
+
+package kotlinx.io.bytestring
+
+import kotlinx.io.bytestring.unsafe.UnsafeByteStringApi
+import kotlinx.io.bytestring.unsafe.UnsafeByteStringOperations
+import org.khronos.webgl.ArrayBuffer
+import org.khronos.webgl.Int8Array
+import org.khronos.webgl.get
+import org.khronos.webgl.set
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class ByteStringConversionsTest {
+    @Test
+    fun int8ArrayToByteString() {
+        assertTrue(Int8Array(0).toByteString().isEmpty())
+
+        val str = Int8Array(byteArrayOf(1, 2, 3, 4).toTypedArray()).toByteString()
+        assertContentEquals(byteArrayOf(1, 2, 3, 4), str.toByteArray())
+    }
+
+    @Test
+    fun arrayBufferToByteString() {
+        assertTrue(ArrayBuffer(0).toByteString().isEmpty())
+
+        val str = Int8Array(byteArrayOf(1, 2, 3, 4).toTypedArray()).buffer.toByteString()
+        assertContentEquals(byteArrayOf(1, 2, 3, 4), str.toByteArray())
+    }
+
+    @Test
+    fun byteStringToInt8Array() {
+        assertEquals(0, ByteString().toInt8Array().length)
+
+        val array = ByteString(1, 2, 3, 4).toInt8Array()
+        for (idx in 0..<3) {
+            assertEquals((idx + 1).toByte(), array[idx], "idx = $idx")
+        }
+    }
+
+    @Test
+    fun byteStringToArrayBuffer() {
+        assertEquals(0, ByteString().toArrayBuffer().byteLength)
+
+        val buffer = ByteString(1, 2, 3, 4).toArrayBuffer()
+        val array = Int8Array(buffer)
+        for (idx in 0..<3) {
+            assertEquals((idx + 1).toByte(), array[idx], "idx = $idx")
+        }
+    }
+
+    @OptIn(UnsafeByteStringApi::class)
+    @Test
+    fun integrityCheck() {
+        val array = Int8Array(byteArrayOf(1, 2, 3, 4).toTypedArray())
+        val str = array.toByteString()
+
+        array[0] = 42
+        assertContentEquals(byteArrayOf(1, 2, 3, 4), str.toByteArray())
+
+        val array2 = str.toInt8Array()
+        UnsafeByteStringOperations.withByteArrayUnsafe(str) { it[1] = 42 }
+        assertEquals(2, array2[1])
+    }
+}
\ No newline at end of file
diff --git a/bytestring/wasmJs/src/ByteStringsWasmJs.kt b/bytestring/wasmJs/src/ByteStringsWasmJs.kt
new file mode 100644
index 00000000..bb9ad1c1
--- /dev/null
+++ b/bytestring/wasmJs/src/ByteStringsWasmJs.kt
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2017-2024 JetBrains s.r.o. and respective authors and developers.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENCE file.
+ */
+
+package kotlinx.io.bytestring
+
+import org.khronos.webgl.ArrayBuffer
+import org.khronos.webgl.Int8Array
+import org.khronos.webgl.get
+import org.khronos.webgl.set
+
+/**
+ * Returns a new [Int8Array] instance initialized with bytes copied from [this] ByteString.
+ */
+public fun ByteString.toInt8Array(): Int8Array {
+    val res = Int8Array(size)
+    for (idx in this.indices) {
+        res[idx] = this[idx]
+    }
+    return res
+}
+
+/**
+ * Returns a new [ArrayBuffer] instance initialized with bytes copied from [this] ByteString.
+ */
+public fun ByteString.toArrayBuffer(): ArrayBuffer = toInt8Array().buffer
+
+/**
+ * Return a new [ByteString] holding data copied from [this] Int8Array.
+ */
+public fun Int8Array.toByteString(): ByteString {
+    if (length == 0) {
+        return ByteString.EMPTY
+    }
+    val builder = ByteStringBuilder(length)
+    for (idx in 0..<length) {
+        builder.append(this[idx])
+    }
+    return builder.toByteString()
+}
+
+/**
+ * Returns a new [ByteString] holding data copied from [this] ArrayBuffer
+ */
+public fun ArrayBuffer.toByteString(): ByteString = Int8Array(this).toByteString()
\ No newline at end of file
diff --git a/bytestring/wasmJs/test/ByteStringConversionsTest.kt b/bytestring/wasmJs/test/ByteStringConversionsTest.kt
new file mode 100644
index 00000000..3e75a00f
--- /dev/null
+++ b/bytestring/wasmJs/test/ByteStringConversionsTest.kt
@@ -0,0 +1,78 @@
+/*
+ * Copyright 2017-2024 JetBrains s.r.o. and respective authors and developers.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the LICENCE file.
+ */
+
+package kotlinx.io.bytestring
+
+import kotlinx.io.bytestring.unsafe.UnsafeByteStringApi
+import kotlinx.io.bytestring.unsafe.UnsafeByteStringOperations
+import org.khronos.webgl.ArrayBuffer
+import org.khronos.webgl.Int8Array
+import org.khronos.webgl.get
+import org.khronos.webgl.set
+import kotlin.test.Test
+import kotlin.test.assertContentEquals
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+private fun int8ArrayOf(vararg bytes: Byte): Int8Array {
+    val array = Int8Array(bytes.size)
+    for (i in bytes.indices) {
+        array[i] = bytes[i]
+    }
+    return array
+}
+
+class ByteStringConversionsTest {
+    @Test
+    fun int8ArrayToByteString() {
+        assertTrue(Int8Array(0).toByteString().isEmpty())
+
+        val str = int8ArrayOf(1, 2, 3, 4).toByteString()
+        assertContentEquals(byteArrayOf(1, 2, 3, 4), str.toByteArray())
+    }
+
+    @Test
+    fun arrayBufferToByteString() {
+        assertTrue(ArrayBuffer(0).toByteString().isEmpty())
+
+        val str = int8ArrayOf(1, 2, 3, 4).buffer.toByteString()
+        assertContentEquals(byteArrayOf(1, 2, 3, 4), str.toByteArray())
+    }
+
+    @Test
+    fun byteStringToInt8Array() {
+        assertEquals(0, ByteString().toInt8Array().length)
+
+        val array = ByteString(1, 2, 3, 4).toInt8Array()
+        for (idx in 0..<3) {
+            assertEquals((idx + 1).toByte(), array[idx], "idx = $idx")
+        }
+    }
+
+    @Test
+    fun byteStringToArrayBuffer() {
+        assertEquals(0, ByteString().toArrayBuffer().byteLength)
+
+        val buffer = ByteString(1, 2, 3, 4).toArrayBuffer()
+        val array = Int8Array(buffer)
+        for (idx in 0..<3) {
+            assertEquals((idx + 1).toByte(), array[idx], "idx = $idx")
+        }
+    }
+
+    @OptIn(UnsafeByteStringApi::class)
+    @Test
+    fun integrityCheck() {
+        val array = int8ArrayOf(1, 2, 3, 4)
+        val str = array.toByteString()
+
+        array[0] = 42
+        assertContentEquals(byteArrayOf(1, 2, 3, 4), str.toByteArray())
+
+        val array2 = str.toInt8Array()
+        UnsafeByteStringOperations.withByteArrayUnsafe(str) { it[1] = 42 }
+        assertEquals(2, array2[1])
+    }
+}
\ No newline at end of file