diff --git a/README.md b/README.md
index 88b3a8410..f6348dd1d 100644
--- a/README.md
+++ b/README.md
@@ -12,10 +12,7 @@ Supports only version 3 of the Protocol Buffers language.
 
 ### Features
 - Idiomatic and concise [Kotlin builder DSL](#generated-code)
-- Protokt-specific options: [non-null types (dangerous)](#non-null-fields),
-[wrapper types](#wrapper-types),
-[interface implementation](#interface-implementation),
-and more
+- Protokt-specific options: [wrapper types](#wrapper-types), [interface implementation](#interface-implementation), and more
 - Representation of the well-known types as Kotlin nullable types: `StringValue`
 is represented as `String?`, etc.
 - Multiplatform support for Kotlin JS (beta)
@@ -635,8 +632,7 @@ dependencies {
 ```
 
 Wrapper types that wrap protobuf messages are nullable. For example,
-`java.time.Instant` wraps the well-known type `google.protobuf.Timestamp`. They
-can be made non-nullable by using the non-null option described below.
+`java.time.Instant` wraps the well-known type `google.protobuf.Timestamp`.
 
 Wrapper types that wrap protobuf primitives, for example `java.util.UUID`
 which wraps `bytes`, are nullable when they cannot wrap their wrapped type's 
@@ -658,8 +654,6 @@ google.protobuf.BytesValue nullable_uuid = 3 [
 ];
 ```
 
-This behavior can be overridden with the [`non_null` option](#non-null-fields).
-
 Wrapper types can be repeated:
 
 ```protobuf
@@ -686,41 +680,6 @@ _N.b. Well-known type nullability is implemented with
 for each message defined in
 [wrappers.proto](https://github.com/protocolbuffers/protobuf/blob/main/src/google/protobuf/wrappers.proto)._
 
-### Non-null fields
-If a message has no meaning whatsoever when a particular non-scalar field is
-missing, you can emulate proto2's `required` key word by using the
-`(protokt.v1.property).non_null` option:
-
-```protobuf
-message Sample {}
-
-message NonNullSampleMessage {
-  Sample non_null_sample = 1 [
-    (protokt.v1.property).non_null = true
-  ];
-}
-```
-
-Generated code will not have a nullable type, so the field can be referenced
-without using Kotlin's `!!`.
-
-Oneof fields can also be declared non-null:
-
-```protobuf
-message NonNullSampleMessage {
-  oneof non_null_oneof {
-    option (protokt.v1.oneof).non_null = true;
-
-    string message = 1;
-  }
-}
-```
-
-Note that deserialization of a message with a non-nullable field will fail if the
-message being decoded does not contain an instance of the required field.
-
-This functionality will likely be removed.
-
 ### Interface implementation
 
 #### Messages
@@ -759,21 +718,19 @@ dependencies {
 }
 ```
 
-Messages can also implement interfaces by delegation to one of their fields;
-in this case the delegated interface need not live in a separate project, as
-protokt requires no inspection of it:
+Messages can also implement interfaces by delegation to one of their fields:
 
 ```protobuf
 message ImplementsWithDelegate {
   option (protokt.v1.class).implements = "Model2 by modelTwo";
 
-  ImplementsModel2 model_two = 1 [
-    (protokt.v1.property).non_null = true
-  ];
+  ImplementsModel2 model_two = 1;
 }
 ```
 
-Note that the `by` clause references the field by its lower camel case name.
+Note that the `by` clause references the field by its lower camel case name. 
+Properties on delegate interfaces must be nullable since message fields themselves
+are nullable and may not be present on the wire.
 
 #### Oneof Fields
 
@@ -782,7 +739,7 @@ Oneof fields can declare that they implement an interface with the
 also implement the interface. This allows access of common properties without a
 `when` statement that always ultimately extracts the same property.
 
-Suppose you have a domain object MyObjectWithConfig that has a non-null configuration
+Suppose you have a domain object MyObjectWithConfig that has configuration
 that specifies a third-party server for communication. For flexibility, this
 configuration will be modifiable by the server and versioned by a simple integer.
 To hasten subsequent loading of the configuration, a client may save a resolved
@@ -816,7 +773,6 @@ message MyObjectWithConfig {
   ];
 
   oneof Config {
-    option (protokt.v1.oneof).non_null = true;
     option (protokt.v1.oneof).implements = "com.toasttab.example.Config";
 
     ServerSpecified server_specified = 2;
@@ -836,9 +792,7 @@ message ServerSpecified {
 message ClientResolved {
   option (protokt.v1.class).implements = "com.toasttab.example.Config by config";
 
-  ServerSpecified config = 1 [
-    (protokt.v1.property).non_null = true
-  ];
+  ServerSpecified config = 1;
 
   bytes last_known_address = 2 [
     (protokt.v1.property).wrap = "java.net.InetAddress"
@@ -853,7 +807,7 @@ Protokt will generate:
 public class MyObjectWithConfig private constructor(
   @GeneratedProperty(1)
   public val id: UUID?,
-  public val config: Config,
+  public val config: Config?,
   public val unknownFields: UnknownFieldSet = UnknownFieldSet.empty()
 ) : AbstractMessage() {
 
@@ -906,18 +860,10 @@ accessing the property via a `when` expression:
 
 ```kotlin
 fun printVersion(config: MyObjectWithConfig.Config) {
-    println(config.version)
+    println(config?.version)
 }
 ```
 
-This pattern is dangerous: since the oneof must be marked non-nullable, you
-cannot compatibly add new implementing fields to a producer before a consumer
-is updated with the new generated code. The old consumer will attempt to
-deserialize the new field as an unknown field and the non-null assertion on the
-oneof field during the constructor call will fail.
-
-This functionality will likely be removed.
-
 ### BytesSlice
 
 When reading messages that contain other serialized messages as `bytes` fields,
diff --git a/extensions/protokt-extensions-lite/api/protokt-extensions-lite.api b/extensions/protokt-extensions-lite/api/protokt-extensions-lite.api
index e13ac3b11..2835d21ad 100644
--- a/extensions/protokt-extensions-lite/api/protokt-extensions-lite.api
+++ b/extensions/protokt-extensions-lite/api/protokt-extensions-lite.api
@@ -369,14 +369,13 @@ public final class protokt/v1/EnumValueOptions$Deserializer : protokt/v1/Abstrac
 
 public final class protokt/v1/FieldOptions : protokt/v1/AbstractMessage {
 	public static final field Deserializer Lprotokt/v1/FieldOptions$Deserializer;
-	public synthetic fun <init> (ZLjava/lang/String;ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun copy (Lkotlin/jvm/functions/Function1;)Lprotokt/v1/FieldOptions;
 	public static fun deserialize (Lprotokt/v1/Reader;)Lprotokt/v1/FieldOptions;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getBytesSlice ()Z
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getKeyWrap ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public final fun getValueWrap ()Ljava/lang/String;
 	public final fun getWrap ()Ljava/lang/String;
@@ -393,14 +392,12 @@ public final class protokt/v1/FieldOptions$Builder {
 	public final fun getBytesSlice ()Z
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getKeyWrap ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public final fun getValueWrap ()Ljava/lang/String;
 	public final fun getWrap ()Ljava/lang/String;
 	public final fun setBytesSlice (Z)V
 	public final fun setDeprecationMessage (Ljava/lang/String;)V
 	public final fun setKeyWrap (Ljava/lang/String;)V
-	public final fun setNonNull (Z)V
 	public final fun setUnknownFields (Lprotokt/v1/UnknownFieldSet;)V
 	public final fun setValueWrap (Ljava/lang/String;)V
 	public final fun setWrap (Ljava/lang/String;)V
@@ -593,13 +590,12 @@ public final class protokt/v1/MethodOptions$Deserializer : protokt/v1/AbstractDe
 
 public final class protokt/v1/OneofOptions : protokt/v1/AbstractMessage {
 	public static final field Deserializer Lprotokt/v1/OneofOptions$Deserializer;
-	public synthetic fun <init> (ZLjava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun copy (Lkotlin/jvm/functions/Function1;)Lprotokt/v1/OneofOptions;
 	public static fun deserialize (Lprotokt/v1/Reader;)Lprotokt/v1/OneofOptions;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getImplements ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public fun hashCode ()I
 	public static final fun invoke (Lkotlin/jvm/functions/Function1;)Lprotokt/v1/OneofOptions;
@@ -613,11 +609,9 @@ public final class protokt/v1/OneofOptions$Builder {
 	public final fun build ()Lprotokt/v1/OneofOptions;
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getImplements ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public final fun setDeprecationMessage (Ljava/lang/String;)V
 	public final fun setImplements (Ljava/lang/String;)V
-	public final fun setNonNull (Z)V
 	public final fun setUnknownFields (Lprotokt/v1/UnknownFieldSet;)V
 }
 
diff --git a/extensions/protokt-extensions-lite/src/extensions-proto/protokt/v1/protokt.proto b/extensions/protokt-extensions-lite/src/extensions-proto/protokt/v1/protokt.proto
index 421693853..c535a0f42 100644
--- a/extensions/protokt-extensions-lite/src/extensions-proto/protokt/v1/protokt.proto
+++ b/extensions/protokt-extensions-lite/src/extensions-proto/protokt/v1/protokt.proto
@@ -46,18 +46,6 @@ extend google.protobuf.MessageOptions {
 }
 
 message FieldOptions {
-  // Makes a message-type field non-nullable in the generated Kotlin code.
-  // Beware that deserialization will NPE if the field is missing from the
-  // protobuf payload. Adding a non-null field to an existing message is a
-  // backwards-incompatible change.
-  //
-  // For example:
-  //
-  // message Foo {
-  //   string id = 1 [(protokt.v1.property).non_null = true];
-  // }
-  bool non_null = 1;
-
   // Expose a wrapper class instead of a raw protobuf type.
   //
   // For example:
@@ -76,14 +64,14 @@ message FieldOptions {
   // full qualification is optional.
   //
   // This option can be applied to repeated fields.
-  string wrap = 2;
+  string wrap = 1;
 
   // Maps a bytes field to BytesSlice. If deserialized from a byte array,
   // BytesSlice will point to the source array without copying the subarray.
-  bool bytes_slice = 3;
+  bool bytes_slice = 2;
 
   // Provides a message for deprecation
-  string deprecation_message = 4;
+  string deprecation_message = 3;
 
   // Expose a wrapper class instead of a raw protobuf type for the key type of
   // a map.
@@ -100,7 +88,7 @@ message FieldOptions {
   // class Foo(val map: Map<FooId, String>) ...
   //
   // Scoping rules  are the same as those for declaring regular field wrapper types.
-  string key_wrap = 5;
+  string key_wrap = 4;
 
   // Expose a wrapper class instead of a raw protobuf type for the value type of
   // a map.
@@ -117,7 +105,7 @@ message FieldOptions {
   // class Foo(val map: Map<Int, FooId>) ...
   //
   // Scoping rules  are the same as those for declaring regular field wrapper types.
-  string value_wrap = 6;
+  string value_wrap = 5;
 }
 
 extend google.protobuf.FieldOptions {
@@ -125,30 +113,13 @@ extend google.protobuf.FieldOptions {
 }
 
 message OneofOptions {
-  // Makes a oneof field non-nullable in generated Kotlin code. Beware that
-  // deserialization will NPE if the field is missing from the protobuf payload.
-  // Adding a non-null field to an existing message is a backwards-incompatible
-  // change.
-  //
-  // For example:
-  //
-  // message Message {
-  //   oneof some_field_name {
-  //     option (protokt.v1.oneof).non_null = true;
-  //
-  //     string id = 1;
-  //   }
-  // }
-  //
-  bool non_null = 1;
-
   // Make the sealed class implement an interface, enforcing the presence of a
   // property in each possible variant. Scoping rules  are the same as those
   // for declaring wrapper types.
-  string implements = 2;
+  string implements = 1;
 
   // Provides a message for deprecation
-  string deprecation_message = 3;
+  string deprecation_message = 2;
 }
 
 extend google.protobuf.OneofOptions {
diff --git a/gradle-plugin-integration-test/multiplatform/src/main/proto/testing/test.proto b/gradle-plugin-integration-test/multiplatform/src/main/proto/testing/test.proto
index 2e5acc377..24867861e 100644
--- a/gradle-plugin-integration-test/multiplatform/src/main/proto/testing/test.proto
+++ b/gradle-plugin-integration-test/multiplatform/src/main/proto/testing/test.proto
@@ -34,6 +34,6 @@ message TestMessage {
   }
 
   message Submessage {
-    TestMessage qux = 1 [(protokt.v1.property).non_null = true];
+    TestMessage qux = 1;
   }
 }
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/DeserializerSupport.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/DeserializerSupport.kt
index f2b19ffb6..201043e09 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/DeserializerSupport.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/DeserializerSupport.kt
@@ -17,7 +17,6 @@ package protokt.v1.codegen.generate
 
 import com.squareup.kotlinpoet.CodeBlock
 import com.squareup.kotlinpoet.buildCodeBlock
-import com.squareup.kotlinpoet.withIndent
 import protokt.v1.reflect.FieldType
 
 internal fun deserializeVarInitialState(p: PropertyInfo) =
@@ -28,33 +27,15 @@ internal fun deserializeVarInitialState(p: PropertyInfo) =
     }
 
 internal fun wrapDeserializedValueForConstructor(p: PropertyInfo) =
-    if (p.nonNullOption) {
-        buildCodeBlock {
-            beginControlFlow("requireNotNull(%N)", p.name)
-            add("StringBuilder(\"%N\")\n", p.name)
-            withIndent {
-                add(
-                    (
-                        ".append(\" specified nonnull with (protokt." +
-                            "${if (p.oneof) "oneof" else "property"}).non_null " +
-                            "but was null\")"
-                        ).bindSpaces()
-                )
-                add("\n")
-            }
-            endControlFlowWithoutNewline()
-        }
+    if (p.isMap) {
+        CodeBlock.of("%M(%N)", unmodifiableMap, p.name)
+    } else if (p.repeated) {
+        CodeBlock.of("%M(%N)", unmodifiableList, p.name)
     } else {
-        if (p.isMap) {
-            CodeBlock.of("%M(%N)", unmodifiableMap, p.name)
-        } else if (p.repeated) {
-            CodeBlock.of("%M(%N)", unmodifiableList, p.name)
-        } else {
-            buildCodeBlock {
-                add("%N", p.name)
-                if (p.wrapped && !p.nullable) {
-                    add(" ?: %L", p.defaultValue)
-                }
+        buildCodeBlock {
+            add("%N", p.name)
+            if (p.wrapped && !p.nullable) {
+                add(" ?: %L", p.defaultValue)
             }
         }
     }
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Implements.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Implements.kt
index 3ba0b3ef2..ef0bb4605 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Implements.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Implements.kt
@@ -16,10 +16,15 @@
 package protokt.v1.codegen.generate
 
 import com.squareup.kotlinpoet.ClassName
+import com.squareup.kotlinpoet.FunSpec
+import com.squareup.kotlinpoet.KModifier
+import com.squareup.kotlinpoet.PropertySpec
 import com.squareup.kotlinpoet.TypeSpec
+import com.squareup.kotlinpoet.asTypeName
 import protokt.v1.codegen.generate.CodeGenerator.Context
 import protokt.v1.codegen.util.Message
 import protokt.v1.codegen.util.StandardField
+import kotlin.reflect.KClass
 
 internal object Implements {
     fun StandardField.overrides(
@@ -27,7 +32,7 @@ internal object Implements {
         msg: Message
     ) =
         msg.superInterface(ctx)
-            ?.let { fieldName in ctx.info.context.classLookup.properties(it.canonicalName) }
+            ?.let { fieldName in ctx.info.context.classLookup.properties(it.canonicalName).map { p -> p.name } }
             ?: false
 
     fun TypeSpec.Builder.handleSuperInterface(implements: ClassName?, v: OneofGeneratorInfo? = null) =
@@ -43,27 +48,66 @@ internal object Implements {
 
     fun TypeSpec.Builder.handleSuperInterface(msg: Message, ctx: Context) =
         apply {
-            if (msg.options.protokt.implements.isNotEmpty()) {
-                if (msg.options.protokt.implements.delegates()) {
-                    addSuperinterface(
-                        ClassName.bestGuess(msg.options.protokt.implements.substringBefore(" by ")),
-                        msg.options.protokt.implements.substringAfter(" by ")
-                    )
-                } else {
-                    addSuperinterface(msg.superInterface(ctx)!!)
+            val superInterface = msg.superInterface(ctx)
+            if (superInterface != null) {
+                addSuperinterface(superInterface.`interface`)
+                if (superInterface.delegate != null) {
+                    // can't actually delegate because message types are nullable
+                    delegateProperties(msg, ctx, superInterface.canonicalName, superInterface.delegate)
                 }
             }
         }
 
-    private fun String.delegates() =
-        contains(" by ")
+    private fun TypeSpec.Builder.delegateProperties(msg: Message, ctx: Context, canonicalName: String, fieldName: String) {
+        val fieldsByName = msg.fields.filterIsInstance<StandardField>().associateBy { it.fieldName }
+        val interfaceFields =
+            ctx.info.context.classLookup
+                .properties(canonicalName)
+                .associateBy { it.name }
+
+        val implementFields = interfaceFields.values.filter { it.name !in fieldsByName.keys }
 
-    private fun Message.superInterface(ctx: Context) =
-        options.protokt.implements.let {
-            if (it.isNotEmpty() && !it.delegates()) {
-                inferClassName(it, ctx)
-            } else {
-                null
+        implementFields.forEach {
+            require(it.returnType.isMarkedNullable) {
+                "Delegated properties must be nullable because message types are nullable; " +
+                    "property ${it.name} is non-nullable"
             }
         }
+
+        implementFields.forEach {
+            addProperty(
+                PropertySpec.builder(
+                    it.name,
+                    (it.returnType.classifier as KClass<*>).asTypeName().copy(nullable = true)
+                )
+                    .addModifiers(KModifier.OVERRIDE)
+                    .getter(
+                        FunSpec.getterBuilder()
+                            .addCode("return %L?.%L", fieldName, it.name)
+                            .build()
+                    )
+                    .build()
+            )
+        }
+    }
+
+    private class SuperInterface(
+        val `interface`: ClassName,
+        val delegate: String?
+    ) {
+        val canonicalName = `interface`.canonicalName
+    }
+
+    private fun Message.superInterface(ctx: Context): SuperInterface? {
+        val implements = options.protokt.implements
+        return when {
+            implements.isEmpty() -> null
+            implements.contains(" by ") ->
+                SuperInterface(
+                    inferClassName(implements.substringBefore(" by "), ctx),
+                    implements.substringAfter(" by ")
+                )
+            else -> SuperInterface(inferClassName(implements, ctx), null)
+        }
+    }
 }
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/MessageSizeGenerator.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/MessageSizeGenerator.kt
index c30a97008..991db1986 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/MessageSizeGenerator.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/MessageSizeGenerator.kt
@@ -20,7 +20,6 @@ import com.squareup.kotlinpoet.KModifier
 import com.squareup.kotlinpoet.PropertySpec
 import com.squareup.kotlinpoet.buildCodeBlock
 import protokt.v1.codegen.generate.CodeGenerator.Context
-import protokt.v1.codegen.generate.Nullability.hasNonNullOption
 import protokt.v1.codegen.generate.Wrapper.interceptFieldSizeof
 import protokt.v1.codegen.generate.Wrapper.interceptSizeof
 import protokt.v1.codegen.generate.Wrapper.interceptValueAccess
@@ -56,12 +55,7 @@ private class MessageSizeGenerator(
                 properties,
                 false,
                 { std, _ -> CodeBlock.of("$resultVarName·+=·%L", sizeOf(std, ctx)) },
-                { oneof, std, _ -> sizeofOneof(oneof, std) },
-                {
-                    if (it.hasNonNullOption) {
-                        add("$resultVarName·+=·")
-                    }
-                }
+                { oneof, std, _ -> sizeofOneof(oneof, std) }
             )
 
         return PropertySpec.builder(MESSAGE_SIZE, Int::class)
@@ -88,21 +82,18 @@ private class MessageSizeGenerator(
     }
 
     private fun sizeofOneof(o: Oneof, f: StandardField) =
-        sizeOf(
-            f,
-            ctx,
-            interceptSizeof(
+        CodeBlock.of(
+            "$resultVarName·+=·%L",
+            sizeOf(
                 f,
-                CodeBlock.of("%N.%N", o.fieldName, f.fieldName),
-                ctx
+                ctx,
+                interceptSizeof(
+                    f,
+                    CodeBlock.of("%N.%N", o.fieldName, f.fieldName),
+                    ctx
+                )
             )
-        ).let { s ->
-            if (o.hasNonNullOption) {
-                s
-            } else {
-                CodeBlock.of("$resultVarName·+=·%L", s)
-            }
-        }
+        )
 }
 
 internal fun sizeOf(
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Nullability.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Nullability.kt
index 48110e48c..fea49c911 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Nullability.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Nullability.kt
@@ -23,18 +23,7 @@ import protokt.v1.codegen.util.StandardField
 import protokt.v1.reflect.FieldType
 
 internal object Nullability {
-    val Field.hasNonNullOption
-        get() =
-            when (this) {
-                is StandardField -> options.protokt.nonNull
-                is Oneof -> options.protokt.nonNull
-            }
-
     val Field.nullable
-        get() =
-            isKotlinRepresentationNullable && !hasNonNullOption
-
-    private val Field.isKotlinRepresentationNullable
         get() =
             when (this) {
                 is StandardField -> (type == FieldType.Message && !repeated) || optional
@@ -47,13 +36,6 @@ internal object Nullability {
                 !repeated &&
                 type !in setOf(FieldType.Message, FieldType.Enum)
 
-    fun propertyType(o: Oneof) =
-        if (o.hasNonNullOption) {
-            o.className
-        } else {
-            o.className.copy(nullable = true)
-        }
-
     fun propertyType(f: StandardField, type: TypeName, wrapperRequiresNullability: Boolean) =
         if (f.nullable || wrapperRequiresNullability) {
             type.copy(nullable = true)
@@ -65,7 +47,6 @@ internal object Nullability {
         if (
             f.repeated ||
             f.nullable ||
-            f.isKotlinRepresentationNullable ||
             f.isWrappedNonRepeatedPrimitive
         ) {
             type.copy(nullable = true)
@@ -74,10 +55,7 @@ internal object Nullability {
         }
 
     fun dslPropertyType(f: StandardField, type: TypeName) =
-        if (
-            f.isKotlinRepresentationNullable ||
-            f.isWrappedNonRepeatedPrimitive
-        ) {
+        if (f.nullable || f.isWrappedNonRepeatedPrimitive) {
             type.copy(nullable = true)
         } else {
             type
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/PropertyAnnotator.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/PropertyAnnotator.kt
index 3f4aca019..d53de3ac4 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/PropertyAnnotator.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/PropertyAnnotator.kt
@@ -24,7 +24,6 @@ import protokt.v1.codegen.generate.Deprecation.renderOptions
 import protokt.v1.codegen.generate.Implements.overrides
 import protokt.v1.codegen.generate.Nullability.deserializeType
 import protokt.v1.codegen.generate.Nullability.dslPropertyType
-import protokt.v1.codegen.generate.Nullability.hasNonNullOption
 import protokt.v1.codegen.generate.Nullability.nullable
 import protokt.v1.codegen.generate.Nullability.propertyType
 import protokt.v1.codegen.generate.Wrapper.interceptDefaultValue
@@ -55,19 +54,17 @@ private class PropertyAnnotator(
         return when (field) {
             is StandardField -> {
                 annotateStandard(field).let { type ->
-                    val wrapperRequiresNullability = field.wrapperRequiresNullability(ctx)
                     PropertyInfo(
                         name = field.fieldName,
                         number = field.number,
-                        propertyType = propertyType(field, type, wrapperRequiresNullability),
+                        propertyType = propertyType(field, type, field.wrapperRequiresNullability(ctx)),
                         deserializeType = deserializeType(field, type),
                         builderPropertyType = dslPropertyType(field, type),
                         defaultValue = field.defaultValue(ctx, msg.mapEntry),
                         fieldType = field.type,
                         repeated = field.repeated,
                         mapEntry = field.mapEntry,
-                        nullable = field.nullable || field.optional || wrapperRequiresNullability,
-                        nonNullOption = field.hasNonNullOption,
+                        nullable = field.nullable || field.optional,
                         overrides = field.overrides(ctx, msg),
                         wrapped = field.wrapped,
                         documentation = documentation,
@@ -78,13 +75,12 @@ private class PropertyAnnotator(
             is Oneof ->
                 PropertyInfo(
                     name = field.fieldName,
-                    propertyType = propertyType(field),
+                    propertyType = field.className.copy(nullable = true),
                     deserializeType = field.className.copy(nullable = true),
                     builderPropertyType = field.className.copy(nullable = true),
                     defaultValue = field.defaultValue(ctx, false),
                     oneof = true,
                     nullable = field.nullable,
-                    nonNullOption = field.hasNonNullOption,
                     documentation = documentation
                 )
         }
@@ -141,7 +137,6 @@ internal class PropertyInfo(
     val builderPropertyType: TypeName,
     val defaultValue: CodeBlock,
     val nullable: Boolean,
-    val nonNullOption: Boolean,
     val fieldType: FieldType? = null,
     val repeated: Boolean = false,
     val mapEntry: Message? = null,
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/SerializeAndSizeSupport.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/SerializeAndSizeSupport.kt
index 9f11295f2..406f10e51 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/SerializeAndSizeSupport.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/SerializeAndSizeSupport.kt
@@ -19,7 +19,6 @@ import com.squareup.kotlinpoet.CodeBlock
 import com.squareup.kotlinpoet.PropertySpec
 import com.squareup.kotlinpoet.buildCodeBlock
 import protokt.v1.codegen.generate.CodeGenerator.Context
-import protokt.v1.codegen.generate.Nullability.hasNonNullOption
 import protokt.v1.codegen.generate.Nullability.nullable
 import protokt.v1.codegen.generate.Wrapper.interceptValueAccess
 import protokt.v1.codegen.generate.Wrapper.wrapperRequiresNullability
@@ -34,8 +33,7 @@ internal fun Message.mapFields(
     properties: List<PropertySpec>,
     skipConditionalForUnpackedRepeatedFields: Boolean,
     std: (StandardField, PropertySpec) -> CodeBlock,
-    oneof: (Oneof, StandardField, PropertySpec) -> CodeBlock,
-    oneofPreControlFlow: CodeBlock.Builder.(Oneof) -> Unit = {}
+    oneof: (Oneof, StandardField, PropertySpec) -> CodeBlock
 ): List<CodeBlock> =
     fields.zip(properties)
         .map { (field, property) ->
@@ -43,7 +41,7 @@ internal fun Message.mapFields(
                 is StandardField ->
                     standardFieldExecution(ctx, field, skipConditionalForUnpackedRepeatedFields) { std(field, property) }
                 is Oneof ->
-                    oneofFieldExecution(field, { oneof(field, it, property) }, oneofPreControlFlow)
+                    oneofFieldExecution(field) { oneof(field, it, property) }
             }
         }
 
@@ -58,18 +56,14 @@ private fun standardFieldExecution(
         add("\n")
     }
 
-    return if (field.hasNonNullOption) {
-        buildCodeBlock { addStmt() }
-    } else {
-        buildCodeBlock {
-            if (field.repeated && !field.packed && skipConditional) {
-                // skip isNotEmpty check when not packed; will short circuit correctly
-                addStmt()
-            } else {
-                beginControlFlow("if (%L)", field.nonDefault(ctx))
-                addStmt()
-                endControlFlow()
-            }
+    return buildCodeBlock {
+        if (field.repeated && !field.packed && skipConditional) {
+            // skip isNotEmpty check when not packed; will short circuit correctly
+            addStmt()
+        } else {
+            beginControlFlow("if (%L)", field.nonDefault(ctx))
+            addStmt()
+            endControlFlow()
         }
     }
 }
@@ -97,11 +91,9 @@ private fun StandardField.nonDefault(ctx: Context): CodeBlock {
 
 private fun oneofFieldExecution(
     field: Oneof,
-    stmt: (StandardField) -> CodeBlock,
-    preControlFlow: CodeBlock.Builder.(Oneof) -> Unit
+    stmt: (StandardField) -> CodeBlock
 ): CodeBlock =
     buildCodeBlock {
-        preControlFlow(field)
         beginControlFlow("when (%N)", field.fieldName)
         oneofInstanceConditionals(field) { stmt(it) }.forEach(::add)
         endControlFlow()
@@ -114,14 +106,7 @@ private fun oneofInstanceConditionals(f: Oneof, stmt: (StandardField) -> CodeBlo
             buildCodeBlock {
                 addStatement("is·%T·->\n%L", f.qualify(it), stmt(it))
             }
-        }
-        .let {
-            if (f.hasNonNullOption) {
-                it
-            } else {
-                it + buildCodeBlock { addStatement("null·->·Unit") }
-            }
-        }
+        } + buildCodeBlock { addStatement("null·->·Unit") }
 
 internal fun Oneof.qualify(f: StandardField) =
     className.nestedClass(fieldTypeNames.getValue(f.fieldName))
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Wrapper.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Wrapper.kt
index 528e4b322..dab259aa8 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Wrapper.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/generate/Wrapper.kt
@@ -24,7 +24,6 @@ import protokt.v1.BytesSlice
 import protokt.v1.Converter
 import protokt.v1.OptimizedSizeOfConverter
 import protokt.v1.codegen.generate.CodeGenerator.Context
-import protokt.v1.codegen.generate.Nullability.hasNonNullOption
 import protokt.v1.codegen.util.GeneratorContext
 import protokt.v1.codegen.util.StandardField
 import protokt.v1.reflect.ClassLookup
@@ -39,7 +38,7 @@ internal object Wrapper {
         get() = wrapWithWellKnownInterception(options.wrap, protoTypeName) != null
 
     fun StandardField.wrapperRequiresNullability(ctx: Context) =
-        wrapperRequiresNonNullOptionForNonNullity(ctx.info.context) && !hasNonNullOption
+        wrapperRequiresNonNullOptionForNonNullity(ctx.info.context)
 
     fun StandardField.wrapperRequiresNonNullOptionForNonNullity(ctx: GeneratorContext) =
         wrapped && withWrapper(ctx) { it.cannotDeserializeDefaultValue && !repeated } ?: false
diff --git a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/util/FieldParser.kt b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/util/FieldParser.kt
index b27f40680..361c2d651 100644
--- a/protokt-codegen/src/main/kotlin/protokt/v1/codegen/util/FieldParser.kt
+++ b/protokt-codegen/src/main/kotlin/protokt/v1/codegen/util/FieldParser.kt
@@ -27,7 +27,6 @@ import com.google.protobuf.DescriptorProtos.FileDescriptorProto
 import com.google.protobuf.DescriptorProtos.OneofDescriptorProto
 import com.squareup.kotlinpoet.ClassName
 import com.toasttab.protokt.v1.ProtoktProtos
-import protokt.v1.codegen.generate.Wrapper.wrapperRequiresNonNullOptionForNonNullity
 import protokt.v1.codegen.util.ErrorContext.withFieldName
 import protokt.v1.reflect.FieldType
 import protokt.v1.reflect.typeName
@@ -153,10 +152,6 @@ internal class FieldParser(
             index = idx
         )
 
-        if (protoktOptions.nonNull) {
-            validateNonNullOption(fdp, result, withinOneof, optional)
-        }
-
         return result
     }
 
@@ -220,51 +215,4 @@ internal class FieldParser(
                     // the default value for an unset boolean is false.
                     (ctx.proto3 && (!fdp.options.hasPacked() || (fdp.options.hasPacked() && fdp.options.packed)))
                 )
-
-    private fun validateNonNullOption(
-        fdp: FieldDescriptorProto,
-        field: StandardField,
-        withinOneof: Boolean,
-        optional: Boolean
-    ) {
-        fun FieldType.typeName() =
-            this::class.simpleName!!.lowercase()
-
-        fun name(field: StandardField) =
-            if (field.type == FieldType.Enum) {
-                field.protoTypeName
-            } else {
-                field.type.typeName()
-            }
-
-        val typeName =
-            when (field.type) {
-                FieldType.Enum, FieldType.Message -> fdp.typeName
-                else -> field.type.typeName()
-            }
-
-        require(!optional) {
-            "(protokt.property).non_null is not applicable to optional fields " +
-                "and is inapplicable to optional $typeName"
-        }
-        require(!withinOneof) {
-            "(protokt.property).non_null is only applicable to top level types " +
-                "and is inapplicable to oneof field $typeName"
-        }
-
-        require((field.type == FieldType.Message && !field.repeated) || field.wrapperRequiresNonNullOptionForNonNullity(ctx)) {
-            "(protokt.property).non_null is only applicable to message types " +
-                "and is inapplicable to non-message " +
-                when {
-                    field.mapEntry != null ->
-                        "map<${name(field.mapKey)}, ${name(field.mapValue)}>"
-
-                    field.repeated ->
-                        "repeated $typeName"
-
-                    else ->
-                        field.type.typeName()
-                }
-        }
-    }
 }
diff --git a/protokt-codegen/src/test/kotlin/protokt/v1/codegen/ImplementDelegationTest.kt b/protokt-codegen/src/test/kotlin/protokt/v1/codegen/ImplementDelegationTest.kt
new file mode 100644
index 000000000..b44e21209
--- /dev/null
+++ b/protokt-codegen/src/test/kotlin/protokt/v1/codegen/ImplementDelegationTest.kt
@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2023 Toast, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package protokt.v1.codegen
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class ImplementDelegationTest : AbstractProtoktCodegenTest() {
+    @Test
+    fun `delegate to interface with non-null property`() {
+        val result = runPlugin("implement_by_delegate_with_non_null_property.proto") as Failure
+
+        assertThat(result.err)
+            .contains("Delegated properties must be nullable because message types are nullable; property id is non-nullable")
+    }
+}
+
+@Suppress("UNUSED")
+interface Model {
+    val id: String
+}
diff --git a/protokt-codegen/src/test/kotlin/protokt/v1/codegen/NonNullValidationTest.kt b/protokt-codegen/src/test/kotlin/protokt/v1/codegen/NonNullValidationTest.kt
deleted file mode 100644
index 5f2b694ea..000000000
--- a/protokt-codegen/src/test/kotlin/protokt/v1/codegen/NonNullValidationTest.kt
+++ /dev/null
@@ -1,140 +0,0 @@
-/*
- * Copyright (c) 2022 Toast, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package protokt.v1.codegen
-
-import com.google.common.truth.Truth
-import org.junit.jupiter.params.ParameterizedTest
-import org.junit.jupiter.params.provider.Arguments
-import org.junit.jupiter.params.provider.MethodSource
-import protokt.v1.reflect.FieldType
-
-class NonNullValidationTest : AbstractProtoktCodegenTest() {
-    @ParameterizedTest
-    @MethodSource("fieldTypes")
-    fun `field with bad non-null option`(fieldType: String, fieldTypeName: String?) {
-        assertFailure(
-            "non_null.proto",
-            fieldType,
-            "Error generating code for file test_file.proto: message TestMessageWithBadNonNullField, field value",
-            "java.lang.IllegalArgumentException: (protokt.property).non_null is only applicable to message types " +
-                "and is inapplicable to non-message " + (fieldTypeName ?: fieldType)
-        )
-    }
-
-    @ParameterizedTest
-    @MethodSource("fieldTypes")
-    fun `field in nested message with bad non-null option`(fieldType: String, fieldTypeName: String?) {
-        assertFailure(
-            "non_null_nested.proto",
-            fieldType,
-            "Error generating code for file test_file.proto: message Outer.TestNestedMessageWithBadNonNullField, field value",
-            "java.lang.IllegalArgumentException: (protokt.property).non_null is only applicable to message types " +
-                "and is inapplicable to non-message " + (fieldTypeName ?: fieldType)
-        )
-    }
-
-    @ParameterizedTest
-    @MethodSource("fieldTypesOneof")
-    fun `oneof type`(fieldType: String, fieldTypeName: String?) {
-        assertFailure(
-            "non_null_oneof.proto",
-            fieldType,
-            "Error generating code for file test_file.proto: message TestMessageWithBadNonNullOneof, field bar",
-            "java.lang.IllegalArgumentException: (protokt.property).non_null is only applicable to top level types " +
-                "and is inapplicable to oneof field " + (fieldTypeName ?: fieldType)
-        )
-    }
-
-    @ParameterizedTest
-    @MethodSource("fieldTypesOptional")
-    fun `optional field`(fieldType: String, fieldTypeName: String?) {
-        assertFailure(
-            "non_null_optional.proto",
-            fieldType,
-            "Error generating code for file test_file.proto: message TestMessageWithBadNonNullOptionalField, field value",
-            "java.lang.IllegalArgumentException: (protokt.property).non_null is not applicable to optional fields " +
-                "and is inapplicable to optional " + (fieldTypeName ?: fieldType)
-        )
-    }
-
-    private fun assertFailure(
-        fileName: String,
-        fieldType: String,
-        line0: String,
-        line1: String
-    ) {
-        val result = runPlugin(fileName) { replace("REPLACE", fieldType) } as Failure
-
-        println(result.err)
-
-        Truth.assertThat(result.exitCode).isEqualTo(-1)
-        Truth.assertThat(result.err.lines()[0]).isEqualTo(line0)
-        Truth.assertThat(result.err.lines()[1]).isEqualTo(line1)
-    }
-
-    companion object {
-        @JvmStatic
-        fun fieldTypes() =
-            mapToArgs(argLists())
-
-        private fun mapToArgs(list: List<*>) =
-            list.map {
-                if (it is String) {
-                    Arguments.of(it, null)
-                } else {
-                    Arguments.of(*(it as List<*>).toTypedArray())
-                }
-            }
-
-        private fun argLists() =
-            ineligibleAnonymousTypes().map { it.simpleName!!.lowercase() } +
-                ineligibleAnonymousTypes().map { "repeated ${it.simpleName!!.lowercase()}" } +
-                listOf(
-                    listOf("Foo", "enum"),
-                    listOf("repeated Foo", "repeated .toasttab.protokt.v1.codegen.testing.Foo"),
-                    listOf("repeated Bar", "repeated .toasttab.protokt.v1.codegen.testing.Bar"),
-                    listOf("map<int32, Foo>", "map<int32, .toasttab.protokt.v1.codegen.testing.Foo>")
-                )
-
-        @JvmStatic
-        fun fieldTypesOptional() =
-            mapToArgs(argListsOptional())
-
-        private fun argListsOptional() =
-            ineligibleAnonymousTypes().map { it.simpleName!!.lowercase() } +
-                listOf(
-                    listOf("Foo", ".toasttab.protokt.v1.codegen.testing.Foo"),
-                    listOf("Bar", ".toasttab.protokt.v1.codegen.testing.Bar")
-                )
-
-        @JvmStatic
-        fun fieldTypesOneof() =
-            mapToArgs(argListsOneof())
-
-        private fun argListsOneof() =
-            ineligibleAnonymousTypes().map { it.simpleName!!.lowercase() } +
-                listOf(
-                    listOf("Foo", ".toasttab.protokt.v1.codegen.testing.Foo"),
-                    listOf("Bar", ".toasttab.protokt.v1.codegen.testing.Bar")
-                )
-
-        private fun ineligibleAnonymousTypes() =
-            FieldType::class
-                .sealedSubclasses
-                .flatMap { it.sealedSubclasses }
-                .filterNot { it in setOf(FieldType.Message::class, FieldType.Enum::class) }
-    }
-}
diff --git a/protokt-codegen/src/test/resources/non_null.proto b/protokt-codegen/src/test/resources/implement_by_delegate_with_non_null_property.proto
similarity index 69%
rename from protokt-codegen/src/test/resources/non_null.proto
rename to protokt-codegen/src/test/resources/implement_by_delegate_with_non_null_property.proto
index ff5818170..df5242907 100644
--- a/protokt-codegen/src/test/resources/non_null.proto
+++ b/protokt-codegen/src/test/resources/implement_by_delegate_with_non_null_property.proto
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022 Toast, Inc.
+ * Copyright (c) 2023 Toast, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,14 +19,14 @@ package toasttab.protokt.v1.codegen.testing;
 
 import "protokt/v1/protokt.proto";
 
-message TestMessageWithBadNonNullField {
-  REPLACE value = 1 [
-    (.protokt.v1.property).non_null = true
-  ];
-}
+message ImplementsModel {
+  option (.protokt.v1.class).implements = "protokt.v1.codegen.Model";
 
-enum Foo {
-  FOO = 0;
+  string id = 1;
 }
 
-message Bar {}
+message ImplementsWithDelegate {
+  option (.protokt.v1.class).implements = "protokt.v1.codegen.Model by model";
+
+  ImplementsModel model = 1;
+}
diff --git a/protokt-codegen/src/test/resources/non_null_nested.proto b/protokt-codegen/src/test/resources/non_null_nested.proto
deleted file mode 100644
index 0253a4979..000000000
--- a/protokt-codegen/src/test/resources/non_null_nested.proto
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * Copyright (c) 2022 Toast, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-syntax = "proto3";
-
-package toasttab.protokt.v1.codegen.testing;
-
-import "protokt/v1/protokt.proto";
-
-message Outer {
-  message TestNestedMessageWithBadNonNullField {
-    REPLACE value = 1 [
-      (.protokt.v1.property).non_null = true
-    ];
-  }
-}
-
-enum Foo {
-  FOO = 0;
-}
-
-message Bar {}
diff --git a/protokt-codegen/src/test/resources/non_null_oneof.proto b/protokt-codegen/src/test/resources/non_null_oneof.proto
deleted file mode 100644
index a0a2f5589..000000000
--- a/protokt-codegen/src/test/resources/non_null_oneof.proto
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright (c) 2022 Toast, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-syntax = "proto3";
-
-package toasttab.protokt.v1.codegen.testing;
-
-import "protokt/v1/protokt.proto";
-
-message TestMessageWithBadNonNullOneof {
-  oneof foo {
-    REPLACE bar = 1 [(.protokt.v1.property).non_null = true];
-  }
-}
-
-message Foo {}
-
-enum Bar {
-  BAR = 0;
-}
diff --git a/protokt-codegen/src/test/resources/non_null_optional.proto b/protokt-codegen/src/test/resources/non_null_optional.proto
deleted file mode 100644
index 00c73ac39..000000000
--- a/protokt-codegen/src/test/resources/non_null_optional.proto
+++ /dev/null
@@ -1,32 +0,0 @@
-/*
- * Copyright (c) 2022 Toast, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-syntax = "proto2";
-
-package toasttab.protokt.v1.codegen.testing;
-
-import "protokt/v1/protokt.proto";
-
-message TestMessageWithBadNonNullOptionalField {
-  optional REPLACE value = 1 [
-    (.protokt.v1.property).non_null = true
-  ];
-}
-
-enum Foo {
-  FOO = 0;
-}
-
-message Bar {}
diff --git a/protokt-reflect/api/protokt-reflect.api b/protokt-reflect/api/protokt-reflect.api
index d951bdb00..1c2211833 100644
--- a/protokt-reflect/api/protokt-reflect.api
+++ b/protokt-reflect/api/protokt-reflect.api
@@ -240,7 +240,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$FieldOptions : com/goog
 	public static final field BYTES_SLICE_FIELD_NUMBER I
 	public static final field DEPRECATION_MESSAGE_FIELD_NUMBER I
 	public static final field KEY_WRAP_FIELD_NUMBER I
-	public static final field NON_NULL_FIELD_NUMBER I
 	public static final field VALUE_WRAP_FIELD_NUMBER I
 	public static final field WRAP_FIELD_NUMBER I
 	public fun equals (Ljava/lang/Object;)Z
@@ -254,7 +253,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$FieldOptions : com/goog
 	public static final fun getDescriptor ()Lcom/google/protobuf/Descriptors$Descriptor;
 	public fun getKeyWrap ()Ljava/lang/String;
 	public fun getKeyWrapBytes ()Lcom/google/protobuf/ByteString;
-	public fun getNonNull ()Z
 	public fun getParserForType ()Lcom/google/protobuf/Parser;
 	public fun getSerializedSize ()I
 	public final fun getUnknownFields ()Lcom/google/protobuf/UnknownFieldSet;
@@ -309,7 +307,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder :
 	public synthetic fun clearField (Lcom/google/protobuf/Descriptors$FieldDescriptor;)Lcom/google/protobuf/Message$Builder;
 	public fun clearField (Lcom/google/protobuf/Descriptors$FieldDescriptor;)Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
 	public fun clearKeyWrap ()Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
-	public fun clearNonNull ()Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
 	public synthetic fun clearOneof (Lcom/google/protobuf/Descriptors$OneofDescriptor;)Lcom/google/protobuf/AbstractMessage$Builder;
 	public synthetic fun clearOneof (Lcom/google/protobuf/Descriptors$OneofDescriptor;)Lcom/google/protobuf/GeneratedMessageV3$Builder;
 	public synthetic fun clearOneof (Lcom/google/protobuf/Descriptors$OneofDescriptor;)Lcom/google/protobuf/Message$Builder;
@@ -333,7 +330,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder :
 	public fun getDescriptorForType ()Lcom/google/protobuf/Descriptors$Descriptor;
 	public fun getKeyWrap ()Ljava/lang/String;
 	public fun getKeyWrapBytes ()Lcom/google/protobuf/ByteString;
-	public fun getNonNull ()Z
 	public fun getValueWrap ()Ljava/lang/String;
 	public fun getValueWrapBytes ()Lcom/google/protobuf/ByteString;
 	public fun getWrap ()Ljava/lang/String;
@@ -360,7 +356,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder :
 	public fun setField (Lcom/google/protobuf/Descriptors$FieldDescriptor;Ljava/lang/Object;)Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
 	public fun setKeyWrap (Ljava/lang/String;)Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
 	public fun setKeyWrapBytes (Lcom/google/protobuf/ByteString;)Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
-	public fun setNonNull (Z)Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
 	public synthetic fun setRepeatedField (Lcom/google/protobuf/Descriptors$FieldDescriptor;ILjava/lang/Object;)Lcom/google/protobuf/GeneratedMessageV3$Builder;
 	public synthetic fun setRepeatedField (Lcom/google/protobuf/Descriptors$FieldDescriptor;ILjava/lang/Object;)Lcom/google/protobuf/Message$Builder;
 	public fun setRepeatedField (Lcom/google/protobuf/Descriptors$FieldDescriptor;ILjava/lang/Object;)Lcom/toasttab/protokt/v1/ProtoktProtos$FieldOptions$Builder;
@@ -379,7 +374,6 @@ public abstract interface class com/toasttab/protokt/v1/ProtoktProtos$FieldOptio
 	public abstract fun getDeprecationMessageBytes ()Lcom/google/protobuf/ByteString;
 	public abstract fun getKeyWrap ()Ljava/lang/String;
 	public abstract fun getKeyWrapBytes ()Lcom/google/protobuf/ByteString;
-	public abstract fun getNonNull ()Z
 	public abstract fun getValueWrap ()Ljava/lang/String;
 	public abstract fun getValueWrapBytes ()Lcom/google/protobuf/ByteString;
 	public abstract fun getWrap ()Ljava/lang/String;
@@ -733,7 +727,6 @@ public abstract interface class com/toasttab/protokt/v1/ProtoktProtos$MethodOpti
 public final class com/toasttab/protokt/v1/ProtoktProtos$OneofOptions : com/google/protobuf/GeneratedMessageV3, com/toasttab/protokt/v1/ProtoktProtos$OneofOptionsOrBuilder {
 	public static final field DEPRECATION_MESSAGE_FIELD_NUMBER I
 	public static final field IMPLEMENTS_FIELD_NUMBER I
-	public static final field NON_NULL_FIELD_NUMBER I
 	public fun equals (Ljava/lang/Object;)Z
 	public static fun getDefaultInstance ()Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions;
 	public synthetic fun getDefaultInstanceForType ()Lcom/google/protobuf/Message;
@@ -744,7 +737,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$OneofOptions : com/goog
 	public static final fun getDescriptor ()Lcom/google/protobuf/Descriptors$Descriptor;
 	public fun getImplements ()Ljava/lang/String;
 	public fun getImplementsBytes ()Lcom/google/protobuf/ByteString;
-	public fun getNonNull ()Z
 	public fun getParserForType ()Lcom/google/protobuf/Parser;
 	public fun getSerializedSize ()I
 	public final fun getUnknownFields ()Lcom/google/protobuf/UnknownFieldSet;
@@ -794,7 +786,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder :
 	public synthetic fun clearField (Lcom/google/protobuf/Descriptors$FieldDescriptor;)Lcom/google/protobuf/Message$Builder;
 	public fun clearField (Lcom/google/protobuf/Descriptors$FieldDescriptor;)Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
 	public fun clearImplements ()Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
-	public fun clearNonNull ()Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
 	public synthetic fun clearOneof (Lcom/google/protobuf/Descriptors$OneofDescriptor;)Lcom/google/protobuf/AbstractMessage$Builder;
 	public synthetic fun clearOneof (Lcom/google/protobuf/Descriptors$OneofDescriptor;)Lcom/google/protobuf/GeneratedMessageV3$Builder;
 	public synthetic fun clearOneof (Lcom/google/protobuf/Descriptors$OneofDescriptor;)Lcom/google/protobuf/Message$Builder;
@@ -815,7 +806,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder :
 	public fun getDescriptorForType ()Lcom/google/protobuf/Descriptors$Descriptor;
 	public fun getImplements ()Ljava/lang/String;
 	public fun getImplementsBytes ()Lcom/google/protobuf/ByteString;
-	public fun getNonNull ()Z
 	public final fun isInitialized ()Z
 	public synthetic fun mergeFrom (Lcom/google/protobuf/CodedInputStream;Lcom/google/protobuf/ExtensionRegistryLite;)Lcom/google/protobuf/AbstractMessage$Builder;
 	public synthetic fun mergeFrom (Lcom/google/protobuf/CodedInputStream;Lcom/google/protobuf/ExtensionRegistryLite;)Lcom/google/protobuf/AbstractMessageLite$Builder;
@@ -837,7 +827,6 @@ public final class com/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder :
 	public fun setField (Lcom/google/protobuf/Descriptors$FieldDescriptor;Ljava/lang/Object;)Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
 	public fun setImplements (Ljava/lang/String;)Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
 	public fun setImplementsBytes (Lcom/google/protobuf/ByteString;)Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
-	public fun setNonNull (Z)Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
 	public synthetic fun setRepeatedField (Lcom/google/protobuf/Descriptors$FieldDescriptor;ILjava/lang/Object;)Lcom/google/protobuf/GeneratedMessageV3$Builder;
 	public synthetic fun setRepeatedField (Lcom/google/protobuf/Descriptors$FieldDescriptor;ILjava/lang/Object;)Lcom/google/protobuf/Message$Builder;
 	public fun setRepeatedField (Lcom/google/protobuf/Descriptors$FieldDescriptor;ILjava/lang/Object;)Lcom/toasttab/protokt/v1/ProtoktProtos$OneofOptions$Builder;
@@ -851,7 +840,6 @@ public abstract interface class com/toasttab/protokt/v1/ProtoktProtos$OneofOptio
 	public abstract fun getDeprecationMessageBytes ()Lcom/google/protobuf/ByteString;
 	public abstract fun getImplements ()Ljava/lang/String;
 	public abstract fun getImplementsBytes ()Lcom/google/protobuf/ByteString;
-	public abstract fun getNonNull ()Z
 }
 
 public final class com/toasttab/protokt/v1/ProtoktProtos$ServiceOptions : com/google/protobuf/GeneratedMessageV3, com/toasttab/protokt/v1/ProtoktProtos$ServiceOptionsOrBuilder {
@@ -1014,14 +1002,13 @@ public final class protokt/v1/EnumValueOptions$Deserializer : protokt/v1/Abstrac
 
 public final class protokt/v1/FieldOptions : protokt/v1/AbstractMessage {
 	public static final field Deserializer Lprotokt/v1/FieldOptions$Deserializer;
-	public synthetic fun <init> (ZLjava/lang/String;ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun copy (Lkotlin/jvm/functions/Function1;)Lprotokt/v1/FieldOptions;
 	public static fun deserialize (Lprotokt/v1/Reader;)Lprotokt/v1/FieldOptions;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getBytesSlice ()Z
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getKeyWrap ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public final fun getValueWrap ()Ljava/lang/String;
 	public final fun getWrap ()Ljava/lang/String;
@@ -1038,14 +1025,12 @@ public final class protokt/v1/FieldOptions$Builder {
 	public final fun getBytesSlice ()Z
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getKeyWrap ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public final fun getValueWrap ()Ljava/lang/String;
 	public final fun getWrap ()Ljava/lang/String;
 	public final fun setBytesSlice (Z)V
 	public final fun setDeprecationMessage (Ljava/lang/String;)V
 	public final fun setKeyWrap (Ljava/lang/String;)V
-	public final fun setNonNull (Z)V
 	public final fun setUnknownFields (Lprotokt/v1/UnknownFieldSet;)V
 	public final fun setValueWrap (Ljava/lang/String;)V
 	public final fun setWrap (Ljava/lang/String;)V
@@ -1155,13 +1140,12 @@ public final class protokt/v1/MethodOptions$Deserializer : protokt/v1/AbstractDe
 
 public final class protokt/v1/OneofOptions : protokt/v1/AbstractMessage {
 	public static final field Deserializer Lprotokt/v1/OneofOptions$Deserializer;
-	public synthetic fun <init> (ZLjava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/String;Lprotokt/v1/UnknownFieldSet;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public final fun copy (Lkotlin/jvm/functions/Function1;)Lprotokt/v1/OneofOptions;
 	public static fun deserialize (Lprotokt/v1/Reader;)Lprotokt/v1/OneofOptions;
 	public fun equals (Ljava/lang/Object;)Z
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getImplements ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public fun hashCode ()I
 	public static final fun invoke (Lkotlin/jvm/functions/Function1;)Lprotokt/v1/OneofOptions;
@@ -1175,11 +1159,9 @@ public final class protokt/v1/OneofOptions$Builder {
 	public final fun build ()Lprotokt/v1/OneofOptions;
 	public final fun getDeprecationMessage ()Ljava/lang/String;
 	public final fun getImplements ()Ljava/lang/String;
-	public final fun getNonNull ()Z
 	public final fun getUnknownFields ()Lprotokt/v1/UnknownFieldSet;
 	public final fun setDeprecationMessage (Ljava/lang/String;)V
 	public final fun setImplements (Ljava/lang/String;)V
-	public final fun setNonNull (Z)V
 	public final fun setUnknownFields (Lprotokt/v1/UnknownFieldSet;)V
 }
 
diff --git a/shared-src/reflect/protokt/v1/reflect/ClassLookup.kt b/shared-src/reflect/protokt/v1/reflect/ClassLookup.kt
index 9a6d766a2..f77fb7d56 100644
--- a/shared-src/reflect/protokt/v1/reflect/ClassLookup.kt
+++ b/shared-src/reflect/protokt/v1/reflect/ClassLookup.kt
@@ -21,6 +21,7 @@ import protokt.v1.OptimizedSizeOfConverter
 import java.io.File
 import java.net.URLClassLoader
 import kotlin.reflect.KClass
+import kotlin.reflect.KProperty
 import kotlin.reflect.full.hasAnnotation
 import kotlin.reflect.full.memberProperties
 
@@ -63,11 +64,11 @@ internal class ClassLookup(classpath: List<String>) {
 
     private val classLookup = mutableMapOf<String, KClass<*>>()
 
-    fun properties(canonicalClassName: String): Collection<String> =
+    fun properties(canonicalClassName: String): Collection<KProperty<*>> =
         try {
             classLookup.getOrPut(canonicalClassName) {
                 classLoader.loadClass(canonicalClassName).kotlin
-            }.memberProperties.map { it.name }
+            }.memberProperties
         } catch (t: Throwable) {
             throw Exception("Class not found: $canonicalClassName")
         }
diff --git a/testing/interop/src/main/proto/protokt/v1/testing/wrappers_dynamic.proto b/testing/interop/src/main/proto/protokt/v1/testing/wrappers_dynamic.proto
index 278ea49f2..13bb58fad 100644
--- a/testing/interop/src/main/proto/protokt/v1/testing/wrappers_dynamic.proto
+++ b/testing/interop/src/main/proto/protokt/v1/testing/wrappers_dynamic.proto
@@ -75,8 +75,6 @@ message Wrappers {
 
 message OneofWrappers {
   oneof wrapped_oneof {
-    option (.protokt.v1.oneof).non_null = true;
-
     bytes uuid_oneof = 2 [
       (.protokt.v1.property).wrap = "java.util.UUID"
     ];
diff --git a/testing/options-api/src/main/kotlin/protokt/v1/testing/IModel2.kt b/testing/options-api/src/main/kotlin/protokt/v1/testing/IModel2.kt
index 256c6cae3..bd10869b6 100644
--- a/testing/options-api/src/main/kotlin/protokt/v1/testing/IModel2.kt
+++ b/testing/options-api/src/main/kotlin/protokt/v1/testing/IModel2.kt
@@ -16,5 +16,5 @@
 package protokt.v1.testing
 
 interface IModel2 {
-    val id: String
+    val id: String?
 }
diff --git a/testing/options/src/main/proto/protokt/v1/testing/message_implements.proto b/testing/options/src/main/proto/protokt/v1/testing/message_implements.proto
index ff568d257..ff69fe627 100644
--- a/testing/options/src/main/proto/protokt/v1/testing/message_implements.proto
+++ b/testing/options/src/main/proto/protokt/v1/testing/message_implements.proto
@@ -38,7 +38,5 @@ message ImplementsModel2 {
 message ImplementsWithDelegate {
   option (.protokt.v1.class).implements = "IModel2 by modelTwo";
 
-  ImplementsModel2 model_two = 1 [
-    (.protokt.v1.property).non_null = true
-  ];
+  ImplementsModel2 model_two = 1;
 }
diff --git a/testing/options/src/main/proto/protokt/v1/testing/non_null_property_and_oneof.proto b/testing/options/src/main/proto/protokt/v1/testing/non_null_property_and_oneof.proto
deleted file mode 100644
index d348af90f..000000000
--- a/testing/options/src/main/proto/protokt/v1/testing/non_null_property_and_oneof.proto
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright (c) 2019 Toast, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-syntax = "proto3";
-
-package protokt.v1.testing;
-
-import "google/protobuf/wrappers.proto";
-import "protokt/v1/protokt.proto";
-
-message NonNullModel {
-  google.protobuf.StringValue non_null_string_value = 1 [
-    (.protokt.v1.property).non_null = true
-  ];
-
-  oneof non_null_oneof {
-    option (.protokt.v1.oneof).non_null = true;
-
-    string message = 2;
-  }
-}
-
-message NonNullModelMirror {
-  google.protobuf.StringValue non_null_string_value = 1;
-
-  oneof non_null_oneof {
-    string message = 2;
-  }
-}
diff --git a/testing/options/src/main/proto/protokt/v1/testing/oneof_implements.proto b/testing/options/src/main/proto/protokt/v1/testing/oneof_implements.proto
index 96b2a21a4..6c7f48c59 100644
--- a/testing/options/src/main/proto/protokt/v1/testing/oneof_implements.proto
+++ b/testing/options/src/main/proto/protokt/v1/testing/oneof_implements.proto
@@ -39,7 +39,6 @@ message ImplementsOneof2 {
 
 message ContainsOneofThatImplements {
   oneof implementing_oneof {
-    option (.protokt.v1.oneof).non_null = true;
     option (.protokt.v1.oneof).implements = "OneofModel";
 
     ImplementsOneof1 implements_one = 1;
diff --git a/testing/options/src/main/proto/protokt/v1/testing/pkg/shared_simple_names_alternate_package.proto b/testing/options/src/main/proto/protokt/v1/testing/pkg/shared_simple_names_alternate_package.proto
index 733a8ae87..7a41d5884 100644
--- a/testing/options/src/main/proto/protokt/v1/testing/pkg/shared_simple_names_alternate_package.proto
+++ b/testing/options/src/main/proto/protokt/v1/testing/pkg/shared_simple_names_alternate_package.proto
@@ -21,17 +21,13 @@ import "google/protobuf/duration.proto";
 import "protokt/v1/protokt.proto";
 
 message ImportsWrapperModel {
-  google.protobuf.Duration native_duration = 1 [
-    (.protokt.v1.property).non_null = true
-  ];
+  google.protobuf.Duration native_duration = 1;
 
   google.protobuf.Duration java_duration = 2 [
-    (.protokt.v1.property).wrap = "java.time.Duration",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "java.time.Duration"
   ];
 
   google.protobuf.Duration superfluous_duration = 3 [
-    (.protokt.v1.property).wrap = "protokt.v1.testing.Duration",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "protokt.v1.testing.Duration"
   ];
 }
diff --git a/testing/options/src/main/proto/protokt/v1/testing/shared_simple_names.proto b/testing/options/src/main/proto/protokt/v1/testing/shared_simple_names.proto
index 8c4c74b1f..79cdbb5ba 100644
--- a/testing/options/src/main/proto/protokt/v1/testing/shared_simple_names.proto
+++ b/testing/options/src/main/proto/protokt/v1/testing/shared_simple_names.proto
@@ -21,17 +21,13 @@ import "google/protobuf/duration.proto";
 import "protokt/v1/protokt.proto";
 
 message ImportsWrapperModel {
-  google.protobuf.Duration native_duration = 1 [
-    (.protokt.v1.property).non_null = true
-  ];
+  google.protobuf.Duration native_duration = 1;
 
   google.protobuf.Duration java_duration = 2 [
-    (.protokt.v1.property).wrap = "java.time.Duration",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "java.time.Duration"
   ];
 
   google.protobuf.Duration superfluous_duration = 3 [
-    (.protokt.v1.property).wrap = "protokt.v1.testing.Duration",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "protokt.v1.testing.Duration"
   ];
 }
diff --git a/testing/options/src/main/proto/protokt/v1/testing/wrapper_types.proto b/testing/options/src/main/proto/protokt/v1/testing/wrapper_types.proto
index 6f45d39ad..98aeb7f55 100644
--- a/testing/options/src/main/proto/protokt/v1/testing/wrapper_types.proto
+++ b/testing/options/src/main/proto/protokt/v1/testing/wrapper_types.proto
@@ -44,18 +44,15 @@ message Wrappers {
   ];
 
   .protokt.v1.InetSocketAddress socket_address = 5 [
-    (.protokt.v1.property).wrap = "java.net.InetSocketAddress",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "java.net.InetSocketAddress"
   ];
 
   google.protobuf.Timestamp instant = 6 [
-    (.protokt.v1.property).wrap = "java.time.Instant",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "java.time.Instant"
   ];
 
   google.protobuf.Duration duration = 7 [
-    (.protokt.v1.property).wrap = "java.time.Duration",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "java.time.Duration"
   ];
 
   string local_date = 8 [
@@ -71,8 +68,7 @@ message Wrappers {
   ];
 
   google.type.Date google_date = 11 [
-    (.protokt.v1.property).wrap = "java.time.LocalDate",
-    (.protokt.v1.property).non_null = true
+    (.protokt.v1.property).wrap = "java.time.LocalDate"
   ];
 
   optional bytes optional_uuid = 12 [
@@ -86,27 +82,10 @@ message Wrappers {
   optional string optional_local_date = 14 [
     (.protokt.v1.property).wrap = "java.time.LocalDate"
   ];
-
-  bytes non_null_uuid = 15 [
-    (.protokt.v1.property).wrap = "java.util.UUID",
-    (.protokt.v1.property).non_null = true
-  ];
-
-  bytes non_null_ip_address = 16 [
-    (.protokt.v1.property).wrap = "java.net.InetAddress",
-    (.protokt.v1.property).non_null = true
-  ];
-
-  string non_null_local_date = 17 [
-    (.protokt.v1.property).wrap = "java.time.LocalDate",
-    (.protokt.v1.property).non_null = true
-  ];
 }
 
 message OneofWrappers {
   oneof wrapped_oneof {
-    option (.protokt.v1.oneof).non_null = true;
-
     bytes id_oneof = 1 [
       (.protokt.v1.property).wrap = "protokt.v1.testing.Id"
     ];
diff --git a/testing/options/src/test/kotlin/protokt/v1/testing/NonNullableTest.kt b/testing/options/src/test/kotlin/protokt/v1/testing/NonNullableTest.kt
deleted file mode 100644
index 29b0dc2b5..000000000
--- a/testing/options/src/test/kotlin/protokt/v1/testing/NonNullableTest.kt
+++ /dev/null
@@ -1,69 +0,0 @@
-/*
- * Copyright (c) 2019 Toast, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package protokt.v1.testing
-
-import com.google.common.truth.Truth.assertThat
-import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.assertThrows
-
-class NonNullableTest {
-    @Test
-    fun `test declared nullability`() {
-        assertThat(
-            NonNullModel::class.propertyIsMarkedNullable("nonNullStringValue")
-        ).isFalse()
-
-        assertThat(
-            NonNullModel::class.propertyIsMarkedNullable("nonNullOneof")
-        ).isFalse()
-    }
-
-    @Test
-    fun `detailed error when attempting to deserialize null field`() {
-        val thrown = assertThrows<IllegalArgumentException> {
-            NonNullModel.deserialize(
-                NonNullModelMirror {
-                    nonNullStringValue = null
-                    nonNullOneof = NonNullModelMirror.NonNullOneof.Message("asdf")
-                }.serialize()
-            )
-        }
-
-        assertThat(thrown).hasMessageThat().apply {
-            contains("nonNullStringValue")
-            contains("was null")
-            contains("(protokt.property).non_null")
-        }
-    }
-
-    @Test
-    fun `detailed error when attempting to deserialize null oneof`() {
-        val thrown = assertThrows<IllegalArgumentException> {
-            NonNullModel.deserialize(
-                NonNullModelMirror {
-                    nonNullStringValue = "asdf"
-                    nonNullOneof = null
-                }.serialize()
-            )
-        }
-
-        assertThat(thrown).hasMessageThat().apply {
-            contains("nonNullOneof")
-            contains("was null")
-            contains("(protokt.oneof).non_null")
-        }
-    }
-}
diff --git a/testing/options/src/test/kotlin/protokt/v1/testing/OneofImplementsTest.kt b/testing/options/src/test/kotlin/protokt/v1/testing/OneofImplementsTest.kt
index 7a5245338..3c86904b8 100644
--- a/testing/options/src/test/kotlin/protokt/v1/testing/OneofImplementsTest.kt
+++ b/testing/options/src/test/kotlin/protokt/v1/testing/OneofImplementsTest.kt
@@ -28,8 +28,8 @@ class OneofImplementsTest {
 
     @Test
     fun `property shared between oneof types can be assigned and accessed without switching`() {
-        val assigned: OneofModel = obj.implementingOneof
+        val assigned: OneofModel? = obj.implementingOneof
 
-        assertThat(assigned.id).isEqualTo(Id("val"))
+        assertThat(assigned?.id).isEqualTo(Id("val"))
     }
 }
diff --git a/testing/options/src/test/kotlin/protokt/v1/testing/WrapperTypesTest.kt b/testing/options/src/test/kotlin/protokt/v1/testing/WrapperTypesTest.kt
index 4b0abc7db..2aab57e95 100644
--- a/testing/options/src/test/kotlin/protokt/v1/testing/WrapperTypesTest.kt
+++ b/testing/options/src/test/kotlin/protokt/v1/testing/WrapperTypesTest.kt
@@ -17,7 +17,6 @@ package protokt.v1.testing
 
 import com.google.common.truth.Truth.assertThat
 import org.junit.jupiter.api.Test
-import org.junit.jupiter.api.assertThrows
 import protokt.v1.Bytes
 import protokt.v1.testing.OneofWrappers.WrappedOneof
 import java.net.InetAddress
@@ -44,9 +43,6 @@ class WrapperTypesTest {
             optionalUuid = UUID.randomUUID()
             optionalIpAddress = InetAddress.getByAddress(byteArrayOf(0, 0, 0, 1))
             optionalLocalDate = LocalDate.of(1950, 10, 4)
-            nonNullUuid = UUID.randomUUID()
-            nonNullIpAddress = InetAddress.getByAddress(byteArrayOf(0, 0, 0, 1))
-            nonNullLocalDate = LocalDate.of(1950, 10, 4)
         }
 
     @Test
@@ -64,21 +60,6 @@ class WrapperTypesTest {
         assertThat(Wrappers::class.propertyIsMarkedNullable("localDate")).isTrue()
     }
 
-    @Test
-    fun `nonnull uuid property is not nullable`() {
-        assertThat(Wrappers::class.propertyIsMarkedNullable("nonNullUuid")).isFalse()
-    }
-
-    @Test
-    fun `nonnull ipAddress property is not nullable`() {
-        assertThat(Wrappers::class.propertyIsMarkedNullable("nonNullIpAddress")).isFalse()
-    }
-
-    @Test
-    fun `nonnull localDate property is not nullable`() {
-        assertThat(Wrappers::class.propertyIsMarkedNullable("nonNullLocalDate")).isFalse()
-    }
-
     @Test
     fun `round trip should preserve model`() {
         assertThat(Wrappers.deserialize(model.serialize())).isEqualTo(model)
@@ -271,7 +252,7 @@ class WrapperTypesTest {
     fun `round trip should preserve socket address oneof`() {
         val deserialized = OneofWrappers.deserialize(
             OneofWrappers {
-                wrappedOneof = WrappedOneof.SocketAddressOneof(model.socketAddress)
+                wrappedOneof = WrappedOneof.SocketAddressOneof(model.socketAddress!!)
             }.serialize()
         )
 
@@ -284,7 +265,7 @@ class WrapperTypesTest {
     fun `round trip should preserve instant oneof`() {
         val deserialized = OneofWrappers.deserialize(
             OneofWrappers {
-                wrappedOneof = WrappedOneof.InstantOneof(model.instant)
+                wrappedOneof = WrappedOneof.InstantOneof(model.instant!!)
             }.serialize()
         )
 
@@ -297,7 +278,7 @@ class WrapperTypesTest {
     fun `round trip should preserve duration oneof`() {
         val deserialized = OneofWrappers.deserialize(
             OneofWrappers {
-                wrappedOneof = WrappedOneof.DurationOneof(model.duration)
+                wrappedOneof = WrappedOneof.DurationOneof(model.duration!!)
             }.serialize()
         )
 
@@ -323,7 +304,7 @@ class WrapperTypesTest {
     fun `round trip should preserve google localdate oneof`() {
         val deserialized = OneofWrappers.deserialize(
             OneofWrappers {
-                wrappedOneof = WrappedOneof.GoogleDateOneof(model.googleDate)
+                wrappedOneof = WrappedOneof.GoogleDateOneof(model.googleDate!!)
             }.serialize()
         )
 
@@ -332,16 +313,6 @@ class WrapperTypesTest {
         ).isEqualTo(model.googleDate)
     }
 
-    @Test
-    fun `wrapped message should not be nullable`() {
-        val thrown = assertThrows<IllegalArgumentException> {
-            model.copy { instant = null }
-        }
-
-        assertThat(thrown).hasMessageThat()
-            .isEqualTo("instant specified nonnull with (protokt.property).non_null but was null")
-    }
-
     @Test
     fun `round trip preserves repeated wrapped types`() {
         val list = listOf(UUID.randomUUID())
diff --git a/testing/options/src/test/kotlin/protokt/v1/testing/pkg/SharedSimpleNamesAlternativePackageTest.kt b/testing/options/src/test/kotlin/protokt/v1/testing/pkg/SharedSimpleNamesAlternativePackageTest.kt
index c1e13a4b0..fd4e223e9 100644
--- a/testing/options/src/test/kotlin/protokt/v1/testing/pkg/SharedSimpleNamesAlternativePackageTest.kt
+++ b/testing/options/src/test/kotlin/protokt/v1/testing/pkg/SharedSimpleNamesAlternativePackageTest.kt
@@ -30,11 +30,11 @@ class SharedSimpleNamesAlternativePackageTest {
 
 fun checkDurationTypes(klass: KClass<*>) {
     assertThat(klass.propertyType("nativeDuration"))
-        .isEqualTo(protokt.v1.google.protobuf.Duration::class.createType())
+        .isEqualTo(protokt.v1.google.protobuf.Duration::class.createType(nullable = true))
 
     assertThat(klass.propertyType("javaDuration"))
-        .isEqualTo(java.time.Duration::class.createType())
+        .isEqualTo(java.time.Duration::class.createType(nullable = true))
 
     assertThat(klass.propertyType("superfluousDuration"))
-        .isEqualTo(protokt.v1.testing.Duration::class.createType())
+        .isEqualTo(protokt.v1.testing.Duration::class.createType(nullable = true))
 }