diff --git a/build.gradle.kts b/build.gradle.kts
index e303c6a..36afbba 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -10,7 +10,7 @@ val kmathVersion: String by extra("0.3.1-dev-10")
 
 allprojects {
     group = "center.sciprog"
-    version = "0.2.2-dev-1"
+    version = "0.2.2-dev-3"
 
     repositories {
         mavenLocal()
diff --git a/maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/MercatorProjection.kt b/maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/MercatorProjection.kt
index d09d06d..f7d97d6 100644
--- a/maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/MercatorProjection.kt
+++ b/maps-kt-core/src/commonMain/kotlin/center/sciprog/maps/coordinates/MercatorProjection.kt
@@ -70,7 +70,6 @@ public open class MercatorProjection(
                 )
             )
         }
-
     }
 
     public companion object {
diff --git a/maps-kt-features/build.gradle.kts b/maps-kt-features/build.gradle.kts
index c0e7700..0ca6d61 100644
--- a/maps-kt-features/build.gradle.kts
+++ b/maps-kt-features/build.gradle.kts
@@ -21,4 +21,8 @@ kscience{
     useSerialization{
         json()
     }
+
+    useSerialization(sourceSet = space.kscience.gradle.DependencySourceSet.TEST){
+        protobuf()
+    }
 }
\ No newline at end of file
diff --git a/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/Attribute.kt b/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/Attribute.kt
index 48cce56..492b74f 100644
--- a/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/Attribute.kt
+++ b/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/Attribute.kt
@@ -8,7 +8,9 @@ public interface Attribute<T>
 public abstract class SerializableAttribute<T>(
     public val serialId: String,
     public val serializer: KSerializer<T>,
-) : Attribute<T>
+) : Attribute<T> {
+    override fun toString(): String = serialId
+}
 
 public interface AttributeWithDefault<T> : Attribute<T> {
     public val default: T
diff --git a/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/AttributesSerializer.kt b/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/AttributesSerializer.kt
index a438293..690f923 100644
--- a/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/AttributesSerializer.kt
+++ b/maps-kt-features/src/commonMain/kotlin/center.sciprog.attributes/AttributesSerializer.kt
@@ -34,8 +34,8 @@ public class AttributesSerializer(
 
     override fun serialize(encoder: Encoder, value: Attributes) {
         val json = buildJsonObject {
-            value.content.forEach { (key, value) ->
-                if (key !in serializableAttributes) error("An attribute key $key is not in the list of allowed attributes for this serializer")
+            value.content.forEach { (key: Attribute<*>, value: Any) ->
+                if (key !in serializableAttributes) error("An attribute key '$key' is not in the list of allowed attributes for this serializer")
                 val serializableKey = key as SerializableAttribute
 
                 val json = if (encoder is JsonEncoder) {
diff --git a/maps-kt-features/src/commonTest/kotlin/center/sciprog/attributes/AttributesSerializationTest.kt b/maps-kt-features/src/commonTest/kotlin/center/sciprog/attributes/AttributesSerializationTest.kt
index c438ba8..9c4c84e 100644
--- a/maps-kt-features/src/commonTest/kotlin/center/sciprog/attributes/AttributesSerializationTest.kt
+++ b/maps-kt-features/src/commonTest/kotlin/center/sciprog/attributes/AttributesSerializationTest.kt
@@ -1,36 +1,86 @@
 package center.sciprog.attributes
 
+import kotlinx.serialization.*
 import kotlinx.serialization.json.Json
-import kotlinx.serialization.serializer
+import kotlinx.serialization.modules.SerializersModule
+import kotlinx.serialization.modules.contextual
+import kotlinx.serialization.protobuf.ProtoBuf
+import kotlin.test.Ignore
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
 internal class AttributesSerializationTest {
 
-    internal class TestAttributeContainer(val attributes: Attributes)
+    @Serializable
+    internal class Container(@Contextual val attributes: Attributes) {
+        override fun equals(other: Any?): Boolean = (other as? Container)?.attributes?.equals(attributes) ?: false
+        override fun hashCode(): Int = attributes.hashCode()
 
-//    internal object TestContainerAttribute: SerializableAttribute<TestAttributeContainer>("container", se)
+        override fun toString(): String = attributes.toString()
+    }
 
-    internal object TestAttribute : SerializableAttribute<Map<String, String>>("test", serializer())
+    internal object ContainerAttribute : SerializableAttribute<Container>("container", serializer()) {
+        override fun toString(): String = "container"
+
+    }
+
+    internal object TestAttribute : SerializableAttribute<Map<String, String>>("test", serializer()) {
+        override fun toString(): String = "test"
+    }
 
     @Test
-    fun restore() {
-//
-//        val serializersModule = SerializersModule {
-//            contextual(AttributesSerializer(setOf()))
-//        }
-        val serializer = AttributesSerializer(setOf(NameAttribute, TestAttribute))
-
+    fun restoreFromJson() {
+        val json = Json {
+            serializersModule = SerializersModule {
+                contextual(AttributesSerializer(setOf(NameAttribute, TestAttribute, ContainerAttribute)))
+            }
+        }
 
         val attributes = Attributes {
             NameAttribute("myTest")
             TestAttribute(mapOf("a" to "aa", "b" to "bb"))
+            ContainerAttribute(
+                Container(
+                    Attributes {
+                        TestAttribute(mapOf("a" to "aa", "b" to "bb"))
+                    }
+                )
+            )
         }
 
-        val serialized = Json.encodeToString(serializer, attributes)
+        val serialized: String = json.encodeToString(attributes)
         println(serialized)
 
-        val restored = Json.decodeFromString(serializer, serialized)
+        val restored: Attributes = json.decodeFromString(serialized)
+
+        assertEquals(attributes, restored)
+    }
+
+    @OptIn(ExperimentalSerializationApi::class)
+    @Test
+    @Ignore
+    fun restoreFromProtoBuf() {
+        val protoBuf = ProtoBuf {
+            serializersModule = SerializersModule {
+                contextual(AttributesSerializer(setOf(NameAttribute, TestAttribute, ContainerAttribute)))
+            }
+        }
+
+        val attributes = Attributes {
+            NameAttribute("myTest")
+            TestAttribute(mapOf("a" to "aa", "b" to "bb"))
+            ContainerAttribute(
+                Container(
+                    Attributes {
+                        TestAttribute(mapOf("a" to "aa", "b" to "bb"))
+                    }
+                )
+            )
+        }
+
+        val serialized = protoBuf.encodeToByteArray(attributes)
+
+        val restored: Attributes = protoBuf.decodeFromByteArray(serialized)
 
         assertEquals(attributes, restored)
     }