diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index a0de2a1..e3e6d33 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -12,6 +12,7 @@
           <set>
             <option value="$PROJECT_DIR$" />
             <option value="$PROJECT_DIR$/app" />
+            <option value="$PROJECT_DIR$/backend" />
           </set>
         </option>
       </GradleProjectSettings>
diff --git a/.idea/kotlinc.xml b/.idea/kotlinc.xml
index 2b8a50f..fdf8d99 100644
--- a/.idea/kotlinc.xml
+++ b/.idea/kotlinc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="KotlinJpsPluginSettings">
-    <option name="version" value="1.8.0" />
+    <option name="version" value="1.9.0" />
   </component>
 </project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index 9f71c83..773fe0f 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,4 +1,3 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ExternalStorageConfigurationManager" enabled="true" />
   <component name="ProjectRootManager" version="2" languageLevel="JDK_17" project-jdk-name="jbr-17" project-jdk-type="JavaSDK">
diff --git a/app/build.gradle b/app/build.gradle
index 31d8f6e..d5db5c6 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -48,6 +48,10 @@ android {
 
 dependencies {
     implementation 'androidx.compose.material3:material3:1.1.1'
+    implementation 'androidx.core:core-ktx:+'
+
+    // Kordophone lib
+    implementation project(':backend')
 
     // Navigation
     def nav_version = "2.5.3"
@@ -76,7 +80,7 @@ dependencies {
     implementation "androidx.compose.ui:ui-tooling-preview:$compose_ui_version"
     implementation 'androidx.compose.material:material:1.1.1'
 
-    implementation 'androidx.compose.foundation:foundation:$compose_ui_version'
+    implementation "androidx.compose.foundation:foundation:$compose_ui_version"
 
     debugImplementation "androidx.compose.ui:ui-tooling:$compose_ui_version"
     debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_ui_version"
diff --git a/backend/.gitignore b/backend/.gitignore
new file mode 100644
index 0000000..42afabf
--- /dev/null
+++ b/backend/.gitignore
@@ -0,0 +1 @@
+/build
\ No newline at end of file
diff --git a/backend/build.gradle b/backend/build.gradle
new file mode 100644
index 0000000..aeb90cf
--- /dev/null
+++ b/backend/build.gradle
@@ -0,0 +1,52 @@
+plugins {
+    id 'com.android.library'
+    id 'org.jetbrains.kotlin.android'
+}
+
+android {
+    namespace 'net.buzzert.kordophone.backend'
+    compileSdk 33
+
+    defaultConfig {
+        minSdk 31
+        targetSdk 33
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles "consumer-rules.pro"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+}
+
+dependencies {
+
+    implementation 'androidx.core:core-ktx:1.8.0'
+    implementation 'androidx.appcompat:appcompat:1.4.1'
+    implementation 'com.google.android.material:material:1.5.0'
+    implementation 'androidx.core:core-ktx:+'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
+
+    // Third-party
+    implementation 'com.squareup.retrofit2:retrofit:2.9.0'
+    implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
+    implementation 'com.google.code.gson:gson:2.9.0'
+
+    // https://mvnrepository.com/artifact/org.jetbrains.kotlinx/kotlinx-coroutines-core
+    implementation group: 'org.jetbrains.kotlinx', name: 'kotlinx-coroutines-core', version: '1.7.3', ext: 'pom'
+    testImplementation 'org.jetbrains.kotlinx:kotlinx-coroutines-test:1.7.3'
+    testImplementation 'com.squareup.okhttp3:mockwebserver:4.9.1'
+}
\ No newline at end of file
diff --git a/backend/consumer-rules.pro b/backend/consumer-rules.pro
new file mode 100644
index 0000000..e69de29
diff --git a/backend/proguard-rules.pro b/backend/proguard-rules.pro
new file mode 100644
index 0000000..481bb43
--- /dev/null
+++ b/backend/proguard-rules.pro
@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
\ No newline at end of file
diff --git a/backend/src/androidTest/java/net/buzzert/kordophone/backend/ExampleInstrumentedTest.kt b/backend/src/androidTest/java/net/buzzert/kordophone/backend/ExampleInstrumentedTest.kt
new file mode 100644
index 0000000..ec75aaf
--- /dev/null
+++ b/backend/src/androidTest/java/net/buzzert/kordophone/backend/ExampleInstrumentedTest.kt
@@ -0,0 +1,24 @@
+package net.buzzert.kordophone.backend
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("net.buzzert.kordophone.backend.test", appContext.packageName)
+    }
+}
\ No newline at end of file
diff --git a/backend/src/main/AndroidManifest.xml b/backend/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..87c51ee
--- /dev/null
+++ b/backend/src/main/AndroidManifest.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+<uses-permission android:name="android.permission.INTERNET" />
+</manifest>
\ No newline at end of file
diff --git a/backend/src/main/java/net/buzzert/kordophone/backend/APIClient.kt b/backend/src/main/java/net/buzzert/kordophone/backend/APIClient.kt
new file mode 100644
index 0000000..06785bf
--- /dev/null
+++ b/backend/src/main/java/net/buzzert/kordophone/backend/APIClient.kt
@@ -0,0 +1,16 @@
+package net.buzzert.kordophone.backend
+
+import retrofit2.Retrofit
+import retrofit2.converter.gson.GsonConverterFactory
+import java.net.URL
+
+class APIClient(baseURL: URL) {
+    private val retrofit: Retrofit = Retrofit.Builder()
+        .baseUrl(baseURL)
+        .addConverterFactory(GsonConverterFactory.create())
+        .build()
+
+    fun getClient(): Retrofit {
+        return retrofit
+    }
+}
\ No newline at end of file
diff --git a/backend/src/main/java/net/buzzert/kordophone/backend/APIInterface.kt b/backend/src/main/java/net/buzzert/kordophone/backend/APIInterface.kt
new file mode 100644
index 0000000..e5a63b2
--- /dev/null
+++ b/backend/src/main/java/net/buzzert/kordophone/backend/APIInterface.kt
@@ -0,0 +1,15 @@
+package net.buzzert.kordophone.backend
+
+import net.buzzert.kordophone.backend.model.Conversation
+import okhttp3.ResponseBody
+import retrofit2.Call
+import retrofit2.Response
+import retrofit2.http.GET
+
+interface APIInterface {
+    @GET("/version")
+    suspend fun getVersion(): ResponseBody
+
+    @GET("/conversations")
+    suspend fun getConversations(): Response<List<Conversation>>
+}
\ No newline at end of file
diff --git a/backend/src/main/java/net/buzzert/kordophone/backend/ChatRepository.kt b/backend/src/main/java/net/buzzert/kordophone/backend/ChatRepository.kt
new file mode 100644
index 0000000..545e770
--- /dev/null
+++ b/backend/src/main/java/net/buzzert/kordophone/backend/ChatRepository.kt
@@ -0,0 +1,19 @@
+package net.buzzert.kordophone.backend
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import net.buzzert.kordophone.backend.model.Conversation
+import java.net.URL
+
+class ChatRepository(baseURL: URL) {
+    private val client: APIClient = APIClient(baseURL)
+    private val apiInterface: APIInterface = client.getClient().create(APIInterface::class.java)
+
+    suspend fun getVersion(): String {
+        return apiInterface.getVersion().string()
+    }
+
+    suspend fun fetchConversations(): List<Conversation> {
+        return apiInterface.getConversations().body()!!
+    }
+}
\ No newline at end of file
diff --git a/backend/src/main/java/net/buzzert/kordophone/backend/model/Conversation.kt b/backend/src/main/java/net/buzzert/kordophone/backend/model/Conversation.kt
new file mode 100644
index 0000000..44bef55
--- /dev/null
+++ b/backend/src/main/java/net/buzzert/kordophone/backend/model/Conversation.kt
@@ -0,0 +1,24 @@
+package net.buzzert.kordophone.backend.model
+
+import com.google.gson.annotations.SerializedName
+import java.util.Date
+
+data class Conversation(
+    @SerializedName("date")
+    val date: Date,
+
+    @SerializedName("participantDisplayNames")
+    val participants: List<String>?,
+
+    @SerializedName("displayName")
+    val displayName: String?,
+
+    @SerializedName("unreadCount")
+    val unreadCount: Int,
+
+    @SerializedName("lastMessagePreview")
+    val lastMessagePreview: String,
+
+    @SerializedName("guid")
+    val guid: String,
+)
diff --git a/backend/src/test/java/net/buzzert/kordophone/backend/ExampleUnitTest.kt b/backend/src/test/java/net/buzzert/kordophone/backend/ExampleUnitTest.kt
new file mode 100644
index 0000000..48bbb85
--- /dev/null
+++ b/backend/src/test/java/net/buzzert/kordophone/backend/ExampleUnitTest.kt
@@ -0,0 +1,33 @@
+package net.buzzert.kordophone.backend
+
+import kotlinx.coroutines.runBlocking
+import org.junit.Test
+
+import org.junit.Assert.*
+import java.net.URL
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    val repository = ChatRepository(URL("http://localhost:5738"))
+
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+
+    @Test
+    fun testGetVersion() = runBlocking {
+        val version = repository.getVersion()
+        println("Version: $version")
+    }
+
+    @Test
+    fun testFetchConversations() = runBlocking {
+        val conversations = repository.fetchConversations()
+        println("Conversations: $conversations")
+    }
+}
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index 8595104..6dd2ec6 100644
--- a/build.gradle
+++ b/build.gradle
@@ -8,5 +8,5 @@ buildscript {
 plugins {
     id 'com.android.application' version '7.4.2' apply false
     id 'com.android.library' version '7.4.2' apply false
-    id 'org.jetbrains.kotlin.android' version '1.8.0' apply false
+    id 'org.jetbrains.kotlin.android' version '1.9.0' apply false
 }
\ No newline at end of file
diff --git a/settings.gradle b/settings.gradle
index 97ed009..5d8401c 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -14,3 +14,4 @@ dependencyResolutionManagement {
 }
 rootProject.name = "KordophoneDroid"
 include ':app'
+include ':backend'