diff --git a/library/src/androidTest/java/org/xmtp/android/library/MultiplyNumber.kt b/library/src/androidTest/java/org/xmtp/android/library/MultiplyNumber.kt
new file mode 100644
index 000000000..a16785975
--- /dev/null
+++ b/library/src/androidTest/java/org/xmtp/android/library/MultiplyNumber.kt
@@ -0,0 +1,66 @@
+package org.xmtp.android.library
+
+import com.google.protobuf.kotlin.toByteStringUtf8
+import org.json.JSONObject
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.xmtp.android.library.codecs.ContentCodec
+import org.xmtp.android.library.codecs.ContentTypeId
+import org.xmtp.android.library.codecs.ContentTypeIdBuilder
+import org.xmtp.android.library.codecs.EncodedContent
+import org.xmtp.android.library.messages.walletAddress
+
+data class NumberPair(val a: Double, val b: Double, var result: Double = 0.0)
+
+data class MultiplyNumberCodec(
+    override var contentType: ContentTypeId = ContentTypeIdBuilder.builderFromAuthorityId(
+        authorityId = "your.domain",
+        typeId = "multiply-number",
+        versionMajor = 1,
+        versionMinor = 0
+    )
+) : ContentCodec<NumberPair> {
+    override fun encode(content: NumberPair): EncodedContent {
+        val jsonObject = JSONObject()
+        jsonObject.put("a", content.a)
+        jsonObject.put("b", content.b)
+        return EncodedContent.newBuilder().also {
+            it.type = contentType
+            it.content = jsonObject.toString().toByteStringUtf8()
+        }.build()
+    }
+
+    override fun decode(content: EncodedContent): NumberPair {
+        val jsonObject = JSONObject(content.content.toStringUtf8())
+        val a = jsonObject.getDouble("a")
+        val b = jsonObject.getDouble("b")
+        val numberPair = NumberPair(a, b, a * b)
+        return numberPair
+    }
+
+    override fun fallback(content: NumberPair): String? {
+        return "Error: This app does not support numbers."
+    }
+}
+
+class Test {
+    @Test
+    fun testSendingAndReceivingMultipliedNumber() {
+        Client.register(codec = MultiplyNumberCodec())
+        val fixtures = fixtures()
+        val aliceClient = fixtures.aliceClient
+        val aliceConversation =
+            aliceClient.conversations.newConversation(fixtures.bob.walletAddress)
+        val numberPair = NumberPair(3.0, 2.0)
+        aliceConversation.send(
+            content = numberPair,
+            options = SendOptions(contentType = MultiplyNumberCodec().contentType)
+        )
+        val messages = aliceConversation.messages()
+        assertEquals(messages.size, 1)
+        if (messages.size == 1) {
+            val content: NumberPair? = messages[0].content()
+            assertEquals(6.0, content?.result)
+        }
+    }
+}