diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/functions.ts b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/functions.ts
index c8037e8545..1591b78e61 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/functions.ts
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/functions.ts
@@ -50,13 +50,14 @@ export const toWasmInit: MustacheFn = () => {
       type = type.substring(0, type.length - 1);
     } else {
       const nullType = toWasm()(value, render);
-      const nullable = "Nullable";
+      const nullable = "Option";
       const nullOptional = "| null";
 
       if (nullType.endsWith(nullOptional)) {
         return "null";
       } else if (nullType.startsWith(nullable)) {
-        return `new ${nullType}()`;
+        type = nullType.substring(6);
+        return `Option.None${type}()`;
       }
     }
 
@@ -227,7 +228,7 @@ const applyNullable = (
     ) {
       return `${type} | null`;
     } else {
-      return `Nullable<${type}>`;
+      return `Option<${type}>`;
     }
   } else {
     return type;
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/deserialize_enum.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/deserialize_enum.mustache
index 25ce5f5664..390ae595c0 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/deserialize_enum.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/deserialize_enum.mustache
@@ -8,19 +8,19 @@ if (reader.isNextString()) {
 }
 {{/required}}
 {{^required}}
-let value: Nullable<Types.{{type}}>;
+let value: Option<Types.{{type}}>;
 if (!reader.isNextNil()) {
   if (reader.isNextString()) {
-    value = Nullable.fromValue(
+    value = Option.Some(
       Types.get{{type}}Value(reader.readString())
     );
   } else {
-    value = Nullable.fromValue(
+    value = Option.Some(
       reader.readInt32()
     );
-    Types.sanitize{{type}}Value(value.value);
+    Types.sanitize{{type}}Value(value.unwrap());
   }
 } else {
-  value = Nullable.fromNull<Types.{{type}}>();
+  value = Option.None<Types.{{type}}>();
 }
 {{/required}}
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/index-ts.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/index-ts.mustache
index 1b2b569b9a..af1dfb53fa 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/index-ts.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/index-ts.mustache
@@ -1,7 +1,7 @@
 import {
   wrap_subinvoke,
   wrap_subinvokeImplementation,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/serialization-ts.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/serialization-ts.mustache
index cbeab27539..842613e064 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/serialization-ts.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/module-type/serialization-ts.mustache
@@ -70,7 +70,7 @@ export function write{{name}}Args(
 }
 
 export function deserialize{{name}}Result(buffer: ArrayBuffer): {{#return}}{{#toWasm}}{{toGraphQLType}}{{/toWasm}}{{/return}} {
-  const context: Context =  new Context("Deserializing imported module-type: {{name}}");
+  const context: Context = new Context("Deserializing imported module-type: {{name}}");
   const reader = new ReadDecoder(buffer, context);
 
   {{#return}}
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/object-type/index-ts.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/object-type/index-ts.mustache
index ab841d2923..260f1f14f1 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/object-type/index-ts.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/imported/object-type/index-ts.mustache
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/module-type/serialization-ts.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/module-type/serialization-ts.mustache
index e4ff00abd7..f4a4b0c88e 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/module-type/serialization-ts.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/module-type/serialization-ts.mustache
@@ -9,7 +9,7 @@ export class Input_{{name}} {
 }
 
 export function deserialize{{name}}Args(argsBuf: ArrayBuffer): Input_{{name}} {
-  const context: Context =  new Context("Deserializing module-type: {{name}}");
+  const context: Context = new Context("Deserializing module-type: {{name}}");
   {{#arguments.length}}
   const reader = new ReadDecoder(argsBuf, context);
   let numFields = reader.readMapLength();
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/object-type/index-ts.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/object-type/index-ts.mustache
index 9bdd689ad6..37031594f6 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/object-type/index-ts.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/object-type/index-ts.mustache
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/serialization_imports.mustache b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/serialization_imports.mustache
index 8aeb5aa792..9ded19f5d4 100644
--- a/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/serialization_imports.mustache
+++ b/packages/schema/bind/src/bindings/assemblyscript/wasm-as/templates/serialization_imports.mustache
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/index.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/index.ts
index cd97ce73c5..66c4600c3c 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/index.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/index.ts
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/serialization.ts
index f29e52aad3..ed4fbeff94 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/AnotherType/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/index.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/index.ts
index 0edc7a7894..c6b44c7fda 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/index.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/index.ts
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -21,7 +21,7 @@ export class CustomType {
   str: string;
   optStr: string | null;
   u: u32;
-  optU: Nullable<u32>;
+  optU: Option<u32>;
   m_u8: u8;
   m_u16: u16;
   m_u32: u32;
@@ -38,13 +38,13 @@ export class CustomType {
   bytes: ArrayBuffer;
   optBytes: ArrayBuffer | null;
   m_boolean: bool;
-  optBoolean: Nullable<bool>;
+  optBoolean: Option<bool>;
   uArray: Array<u32>;
   uOptArray: Array<u32> | null;
-  optUOptArray: Array<Nullable<u32>> | null;
+  optUOptArray: Array<Option<u32>> | null;
   optStrOptArray: Array<string | null> | null;
   uArrayArray: Array<Array<u32>>;
-  uOptArrayOptArray: Array<Array<Nullable<u32>> | null>;
+  uOptArrayOptArray: Array<Array<Option<u32>> | null>;
   uArrayOptArrayArray: Array<Array<Array<u32>> | null>;
   crazyArray: Array<Array<Array<Array<u32> | null>> | null> | null;
   object: Types.AnotherType;
@@ -52,9 +52,9 @@ export class CustomType {
   objectArray: Array<Types.AnotherType>;
   optObjectArray: Array<Types.AnotherType | null> | null;
   en: Types.CustomEnum;
-  optEnum: Nullable<Types.CustomEnum>;
+  optEnum: Option<Types.CustomEnum>;
   enumArray: Array<Types.CustomEnum>;
-  optEnumArray: Array<Nullable<Types.CustomEnum>> | null;
+  optEnumArray: Array<Option<Types.CustomEnum>> | null;
 
   static toBuffer(type: CustomType): ArrayBuffer {
     return serializeCustomType(type);
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/serialization.ts
index 2529b4cb63..5b8a71d97a 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/CustomType/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -38,7 +38,7 @@ export function writeCustomType(writer: Write, type: CustomType): void {
   writer.writeString("u");
   writer.writeUInt32(type.u);
   writer.context().pop();
-  writer.context().push("optU", "Nullable<u32>", "writing property");
+  writer.context().push("optU", "Option<u32>", "writing property");
   writer.writeString("optU");
   writer.writeNullableUInt32(type.optU);
   writer.context().pop();
@@ -106,7 +106,7 @@ export function writeCustomType(writer: Write, type: CustomType): void {
   writer.writeString("boolean");
   writer.writeBool(type.m_boolean);
   writer.context().pop();
-  writer.context().push("optBoolean", "Nullable<bool>", "writing property");
+  writer.context().push("optBoolean", "Option<bool>", "writing property");
   writer.writeString("optBoolean");
   writer.writeNullableBool(type.optBoolean);
   writer.context().pop();
@@ -122,9 +122,9 @@ export function writeCustomType(writer: Write, type: CustomType): void {
     writer.writeUInt32(item);
   });
   writer.context().pop();
-  writer.context().push("optUOptArray", "Array<Nullable<u32>> | null", "writing property");
+  writer.context().push("optUOptArray", "Array<Option<u32>> | null", "writing property");
   writer.writeString("optUOptArray");
-  writer.writeNullableArray(type.optUOptArray, (writer: Write, item: Nullable<u32>): void => {
+  writer.writeNullableArray(type.optUOptArray, (writer: Write, item: Option<u32>): void => {
     writer.writeNullableUInt32(item);
   });
   writer.context().pop();
@@ -142,10 +142,10 @@ export function writeCustomType(writer: Write, type: CustomType): void {
     });
   });
   writer.context().pop();
-  writer.context().push("uOptArrayOptArray", "Array<Array<Nullable<u32>> | null>", "writing property");
+  writer.context().push("uOptArrayOptArray", "Array<Array<Option<u32>> | null>", "writing property");
   writer.writeString("uOptArrayOptArray");
-  writer.writeArray(type.uOptArrayOptArray, (writer: Write, item: Array<Nullable<u32>> | null): void => {
-    writer.writeNullableArray(item, (writer: Write, item: Nullable<u32>): void => {
+  writer.writeArray(type.uOptArrayOptArray, (writer: Write, item: Array<Option<u32>> | null): void => {
+    writer.writeNullableArray(item, (writer: Write, item: Option<u32>): void => {
       writer.writeNullableUInt32(item);
     });
   });
@@ -204,7 +204,7 @@ export function writeCustomType(writer: Write, type: CustomType): void {
   writer.writeString("en");
   writer.writeInt32(type.en);
   writer.context().pop();
-  writer.context().push("optEnum", "Nullable<Types.CustomEnum>", "writing property");
+  writer.context().push("optEnum", "Option<Types.CustomEnum>", "writing property");
   writer.writeString("optEnum");
   writer.writeNullableInt32(type.optEnum);
   writer.context().pop();
@@ -214,9 +214,9 @@ export function writeCustomType(writer: Write, type: CustomType): void {
     writer.writeInt32(item);
   });
   writer.context().pop();
-  writer.context().push("optEnumArray", "Array<Nullable<Types.CustomEnum>> | null", "writing property");
+  writer.context().push("optEnumArray", "Array<Option<Types.CustomEnum>> | null", "writing property");
   writer.writeString("optEnumArray");
-  writer.writeNullableArray(type.optEnumArray, (writer: Write, item: Nullable<Types.CustomEnum>): void => {
+  writer.writeNullableArray(type.optEnumArray, (writer: Write, item: Option<Types.CustomEnum>): void => {
     writer.writeNullableInt32(item);
   });
   writer.context().pop();
@@ -236,7 +236,7 @@ export function readCustomType(reader: Read): CustomType {
   let _optStr: string | null = null;
   let _u: u32 = 0;
   let _uSet: bool = false;
-  let _optU: Nullable<u32> = new Nullable<u32>();
+  let _optU: Option<u32> = Option.None<u32>();
   let _u8: u8 = 0;
   let _u8Set: bool = false;
   let _u16: u16 = 0;
@@ -265,15 +265,15 @@ export function readCustomType(reader: Read): CustomType {
   let _optBytes: ArrayBuffer | null = null;
   let _boolean: bool = false;
   let _booleanSet: bool = false;
-  let _optBoolean: Nullable<bool> = new Nullable<bool>();
+  let _optBoolean: Option<bool> = Option.None<bool>();
   let _uArray: Array<u32> = [];
   let _uArraySet: bool = false;
   let _uOptArray: Array<u32> | null = null;
-  let _optUOptArray: Array<Nullable<u32>> | null = null;
+  let _optUOptArray: Array<Option<u32>> | null = null;
   let _optStrOptArray: Array<string | null> | null = null;
   let _uArrayArray: Array<Array<u32>> = [];
   let _uArrayArraySet: bool = false;
-  let _uOptArrayOptArray: Array<Array<Nullable<u32>> | null> = [];
+  let _uOptArrayOptArray: Array<Array<Option<u32>> | null> = [];
   let _uOptArrayOptArraySet: bool = false;
   let _uArrayOptArrayArray: Array<Array<Array<u32>> | null> = [];
   let _uArrayOptArrayArraySet: bool = false;
@@ -286,10 +286,10 @@ export function readCustomType(reader: Read): CustomType {
   let _optObjectArray: Array<Types.AnotherType | null> | null = null;
   let _en: Types.CustomEnum = 0;
   let _enSet: bool = false;
-  let _optEnum: Nullable<Types.CustomEnum> = new Nullable<Types.CustomEnum>();
+  let _optEnum: Option<Types.CustomEnum> = Option.None<Types.CustomEnum>();
   let _enumArray: Array<Types.CustomEnum> = [];
   let _enumArraySet: bool = false;
-  let _optEnumArray: Array<Nullable<Types.CustomEnum>> | null = null;
+  let _optEnumArray: Array<Option<Types.CustomEnum>> | null = null;
 
   while (numFields > 0) {
     numFields--;
@@ -314,7 +314,7 @@ export function readCustomType(reader: Read): CustomType {
       reader.context().pop();
     }
     else if (field == "optU") {
-      reader.context().push(field, "Nullable<u32>", "type found, reading property");
+      reader.context().push(field, "Option<u32>", "type found, reading property");
       _optU = reader.readNullableUInt32();
       reader.context().pop();
     }
@@ -411,7 +411,7 @@ export function readCustomType(reader: Read): CustomType {
       reader.context().pop();
     }
     else if (field == "optBoolean") {
-      reader.context().push(field, "Nullable<bool>", "type found, reading property");
+      reader.context().push(field, "Option<bool>", "type found, reading property");
       _optBoolean = reader.readNullableBool();
       reader.context().pop();
     }
@@ -431,8 +431,8 @@ export function readCustomType(reader: Read): CustomType {
       reader.context().pop();
     }
     else if (field == "optUOptArray") {
-      reader.context().push(field, "Array<Nullable<u32>> | null", "type found, reading property");
-      _optUOptArray = reader.readNullableArray((reader: Read): Nullable<u32> => {
+      reader.context().push(field, "Array<Option<u32>> | null", "type found, reading property");
+      _optUOptArray = reader.readNullableArray((reader: Read): Option<u32> => {
         return reader.readNullableUInt32();
       });
       reader.context().pop();
@@ -455,9 +455,9 @@ export function readCustomType(reader: Read): CustomType {
       reader.context().pop();
     }
     else if (field == "uOptArrayOptArray") {
-      reader.context().push(field, "Array<Array<Nullable<u32>> | null>", "type found, reading property");
-      _uOptArrayOptArray = reader.readArray((reader: Read): Array<Nullable<u32>> | null => {
-        return reader.readNullableArray((reader: Read): Nullable<u32> => {
+      reader.context().push(field, "Array<Array<Option<u32>> | null>", "type found, reading property");
+      _uOptArrayOptArray = reader.readArray((reader: Read): Array<Option<u32>> | null => {
+        return reader.readNullableArray((reader: Read): Option<u32> => {
           return reader.readNullableUInt32();
         });
       });
@@ -539,21 +539,21 @@ export function readCustomType(reader: Read): CustomType {
       reader.context().pop();
     }
     else if (field == "optEnum") {
-      reader.context().push(field, "Nullable<Types.CustomEnum>", "type found, reading property");
-      let value: Nullable<Types.CustomEnum>;
+      reader.context().push(field, "Option<Types.CustomEnum>", "type found, reading property");
+      let value: Option<Types.CustomEnum>;
       if (!reader.isNextNil()) {
         if (reader.isNextString()) {
-          value = Nullable.fromValue(
+          value = Option.Some(
             Types.getCustomEnumValue(reader.readString())
           );
         } else {
-          value = Nullable.fromValue(
+          value = Option.Some(
             reader.readInt32()
           );
-          Types.sanitizeCustomEnumValue(value.value);
+          Types.sanitizeCustomEnumValue(value.unwrap());
         }
       } else {
-        value = Nullable.fromNull<Types.CustomEnum>();
+        value = Option.None<Types.CustomEnum>();
       }
       _optEnum = value;
       reader.context().pop();
@@ -574,22 +574,22 @@ export function readCustomType(reader: Read): CustomType {
       reader.context().pop();
     }
     else if (field == "optEnumArray") {
-      reader.context().push(field, "Array<Nullable<Types.CustomEnum>> | null", "type found, reading property");
-      _optEnumArray = reader.readNullableArray((reader: Read): Nullable<Types.CustomEnum> => {
-        let value: Nullable<Types.CustomEnum>;
+      reader.context().push(field, "Array<Option<Types.CustomEnum>> | null", "type found, reading property");
+      _optEnumArray = reader.readNullableArray((reader: Read): Option<Types.CustomEnum> => {
+        let value: Option<Types.CustomEnum>;
         if (!reader.isNextNil()) {
           if (reader.isNextString()) {
-            value = Nullable.fromValue(
+            value = Option.Some(
               Types.getCustomEnumValue(reader.readString())
             );
           } else {
-            value = Nullable.fromValue(
+            value = Option.Some(
               reader.readInt32()
             );
-            Types.sanitizeCustomEnumValue(value.value);
+            Types.sanitizeCustomEnumValue(value.unwrap());
           }
         } else {
-          value = Nullable.fromNull<Types.CustomEnum>();
+          value = Option.None<Types.CustomEnum>();
         }
         return value;
       });
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/index.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/index.ts
index 09dee2ac73..904a3bdb79 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/index.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/index.ts
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -20,7 +20,7 @@ import * as Types from "..";
 export class Env {
   prop: string;
   optProp: string | null;
-  optMap: Map<string, Nullable<i32>> | null;
+  optMap: Map<string, Option<i32>> | null;
 
   static toBuffer(type: Env): ArrayBuffer {
     return serializeEnv(type);
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/serialization.ts
index 601434c3e0..e83f1c9ca1 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/Env/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -34,11 +34,11 @@ export function writeEnv(writer: Write, type: Env): void {
   writer.writeString("optProp");
   writer.writeNullableString(type.optProp);
   writer.context().pop();
-  writer.context().push("optMap", "Map<string, Nullable<i32>> | null", "writing property");
+  writer.context().push("optMap", "Map<string, Option<i32>> | null", "writing property");
   writer.writeString("optMap");
   writer.writeNullableExtGenericMap(type.optMap, (writer: Write, key: string) => {
     writer.writeString(key);
-  }, (writer: Write, value: Nullable<i32>): void => {
+  }, (writer: Write, value: Option<i32>): void => {
     writer.writeNullableInt32(value);
   });
   writer.context().pop();
@@ -56,7 +56,7 @@ export function readEnv(reader: Read): Env {
   let _prop: string = "";
   let _propSet: bool = false;
   let _optProp: string | null = null;
-  let _optMap: Map<string, Nullable<i32>> | null = null;
+  let _optMap: Map<string, Option<i32>> | null = null;
 
   while (numFields > 0) {
     numFields--;
@@ -75,10 +75,10 @@ export function readEnv(reader: Read): Env {
       reader.context().pop();
     }
     else if (field == "optMap") {
-      reader.context().push(field, "Map<string, Nullable<i32>> | null", "type found, reading property");
+      reader.context().push(field, "Map<string, Option<i32>> | null", "type found, reading property");
       _optMap = reader.readNullableExtGenericMap((reader: Read): string => {
         return reader.readString();
-      }, (reader: Read): Nullable<i32> => {
+      }, (reader: Read): Option<i32> => {
         return reader.readNullableInt32();
       });
       reader.context().pop();
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/Module/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/Module/serialization.ts
index 6ee48d0a3e..f214d2abae 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/Module/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/Module/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -16,14 +16,14 @@ export class Input_moduleMethod {
   str: string;
   optStr: string | null;
   en: Types.CustomEnum;
-  optEnum: Nullable<Types.CustomEnum>;
+  optEnum: Option<Types.CustomEnum>;
   enumArray: Array<Types.CustomEnum>;
-  optEnumArray: Array<Nullable<Types.CustomEnum>> | null;
+  optEnumArray: Array<Option<Types.CustomEnum>> | null;
   map: Map<string, i32>;
 }
 
 export function deserializemoduleMethodArgs(argsBuf: ArrayBuffer): Input_moduleMethod {
-  const context: Context =  new Context("Deserializing module-type: moduleMethod");
+  const context: Context = new Context("Deserializing module-type: moduleMethod");
   const reader = new ReadDecoder(argsBuf, context);
   let numFields = reader.readMapLength();
 
@@ -32,10 +32,10 @@ export function deserializemoduleMethodArgs(argsBuf: ArrayBuffer): Input_moduleM
   let _optStr: string | null = null;
   let _en: Types.CustomEnum = 0;
   let _enSet: bool = false;
-  let _optEnum: Nullable<Types.CustomEnum> = new Nullable<Types.CustomEnum>();
+  let _optEnum: Option<Types.CustomEnum> = Option.None<Types.CustomEnum>();
   let _enumArray: Array<Types.CustomEnum> = [];
   let _enumArraySet: bool = false;
-  let _optEnumArray: Array<Nullable<Types.CustomEnum>> | null = null;
+  let _optEnumArray: Array<Option<Types.CustomEnum>> | null = null;
   let _map: Map<string, i32> = new Map<string, i32>();
   let _mapSet: bool = false;
 
@@ -69,21 +69,21 @@ export function deserializemoduleMethodArgs(argsBuf: ArrayBuffer): Input_moduleM
       reader.context().pop();
     }
     else if (field == "optEnum") {
-      reader.context().push(field, "Nullable<Types.CustomEnum>", "type found, reading property");
-      let value: Nullable<Types.CustomEnum>;
+      reader.context().push(field, "Option<Types.CustomEnum>", "type found, reading property");
+      let value: Option<Types.CustomEnum>;
       if (!reader.isNextNil()) {
         if (reader.isNextString()) {
-          value = Nullable.fromValue(
+          value = Option.Some(
             Types.getCustomEnumValue(reader.readString())
           );
         } else {
-          value = Nullable.fromValue(
+          value = Option.Some(
             reader.readInt32()
           );
-          Types.sanitizeCustomEnumValue(value.value);
+          Types.sanitizeCustomEnumValue(value.unwrap());
         }
       } else {
-        value = Nullable.fromNull<Types.CustomEnum>();
+        value = Option.None<Types.CustomEnum>();
       }
       _optEnum = value;
       reader.context().pop();
@@ -104,22 +104,22 @@ export function deserializemoduleMethodArgs(argsBuf: ArrayBuffer): Input_moduleM
       reader.context().pop();
     }
     else if (field == "optEnumArray") {
-      reader.context().push(field, "Array<Nullable<Types.CustomEnum>> | null", "type found, reading property");
-      _optEnumArray = reader.readNullableArray((reader: Read): Nullable<Types.CustomEnum> => {
-        let value: Nullable<Types.CustomEnum>;
+      reader.context().push(field, "Array<Option<Types.CustomEnum>> | null", "type found, reading property");
+      _optEnumArray = reader.readNullableArray((reader: Read): Option<Types.CustomEnum> => {
+        let value: Option<Types.CustomEnum>;
         if (!reader.isNextNil()) {
           if (reader.isNextString()) {
-            value = Nullable.fromValue(
+            value = Option.Some(
               Types.getCustomEnumValue(reader.readString())
             );
           } else {
-            value = Nullable.fromValue(
+            value = Option.Some(
               reader.readInt32()
             );
-            Types.sanitizeCustomEnumValue(value.value);
+            Types.sanitizeCustomEnumValue(value.unwrap());
           }
         } else {
-          value = Nullable.fromNull<Types.CustomEnum>();
+          value = Option.None<Types.CustomEnum>();
         }
         return value;
       });
@@ -187,7 +187,7 @@ export class Input_objectMethod {
 }
 
 export function deserializeobjectMethodArgs(argsBuf: ArrayBuffer): Input_objectMethod {
-  const context: Context =  new Context("Deserializing module-type: objectMethod");
+  const context: Context = new Context("Deserializing module-type: objectMethod");
   const reader = new ReadDecoder(argsBuf, context);
   let numFields = reader.readMapLength();
 
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/index.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/index.ts
index 6a52f417bb..2b53e96219 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/index.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/index.ts
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/serialization.ts
index cfbe766951..98b67d08ff 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_AnotherObject/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/index.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/index.ts
index 5246bae2bd..859818f55b 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/index.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/index.ts
@@ -1,7 +1,7 @@
 import {
   wrap_subinvoke,
   wrap_subinvokeImplementation,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/serialization.ts
index 65a08566f7..d1bb72d7e5 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Module/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -16,16 +16,16 @@ export class Input_importedMethod {
   str: string;
   optStr: string | null;
   u: u32;
-  optU: Nullable<u32>;
-  uArrayArray: Array<Array<Nullable<u32>> | null>;
+  optU: Option<u32>;
+  uArrayArray: Array<Array<Option<u32>> | null>;
   object: Types.TestImport_Object;
   optObject: Types.TestImport_Object | null;
   objectArray: Array<Types.TestImport_Object>;
   optObjectArray: Array<Types.TestImport_Object | null> | null;
   en: Types.TestImport_Enum;
-  optEnum: Nullable<Types.TestImport_Enum>;
+  optEnum: Option<Types.TestImport_Enum>;
   enumArray: Array<Types.TestImport_Enum>;
-  optEnumArray: Array<Nullable<Types.TestImport_Enum>> | null;
+  optEnumArray: Array<Option<Types.TestImport_Enum>> | null;
 }
 
 export function serializeimportedMethodArgs(input: Input_importedMethod): ArrayBuffer {
@@ -56,14 +56,14 @@ export function writeimportedMethodArgs(
   writer.writeString("u");
   writer.writeUInt32(input.u);
   writer.context().pop();
-  writer.context().push("optU", "Nullable<u32>", "writing property");
+  writer.context().push("optU", "Option<u32>", "writing property");
   writer.writeString("optU");
   writer.writeNullableUInt32(input.optU);
   writer.context().pop();
-  writer.context().push("uArrayArray", "Array<Array<Nullable<u32>> | null>", "writing property");
+  writer.context().push("uArrayArray", "Array<Array<Option<u32>> | null>", "writing property");
   writer.writeString("uArrayArray");
-  writer.writeArray(input.uArrayArray, (writer: Write, item: Array<Nullable<u32>> | null): void => {
-    writer.writeNullableArray(item, (writer: Write, item: Nullable<u32>): void => {
+  writer.writeArray(input.uArrayArray, (writer: Write, item: Array<Option<u32>> | null): void => {
+    writer.writeNullableArray(item, (writer: Write, item: Option<u32>): void => {
       writer.writeNullableUInt32(item);
     });
   });
@@ -100,7 +100,7 @@ export function writeimportedMethodArgs(
   writer.writeString("en");
   writer.writeInt32(input.en);
   writer.context().pop();
-  writer.context().push("optEnum", "Nullable<Types.TestImport_Enum>", "writing property");
+  writer.context().push("optEnum", "Option<Types.TestImport_Enum>", "writing property");
   writer.writeString("optEnum");
   writer.writeNullableInt32(input.optEnum);
   writer.context().pop();
@@ -110,16 +110,16 @@ export function writeimportedMethodArgs(
     writer.writeInt32(item);
   });
   writer.context().pop();
-  writer.context().push("optEnumArray", "Array<Nullable<Types.TestImport_Enum>> | null", "writing property");
+  writer.context().push("optEnumArray", "Array<Option<Types.TestImport_Enum>> | null", "writing property");
   writer.writeString("optEnumArray");
-  writer.writeNullableArray(input.optEnumArray, (writer: Write, item: Nullable<Types.TestImport_Enum>): void => {
+  writer.writeNullableArray(input.optEnumArray, (writer: Write, item: Option<Types.TestImport_Enum>): void => {
     writer.writeNullableInt32(item);
   });
   writer.context().pop();
 }
 
 export function deserializeimportedMethodResult(buffer: ArrayBuffer): Types.TestImport_Object | null {
-  const context: Context =  new Context("Deserializing imported module-type: importedMethod");
+  const context: Context = new Context("Deserializing imported module-type: importedMethod");
   const reader = new ReadDecoder(buffer, context);
 
   reader.context().push("importedMethod", "Types.TestImport_Object | null", "reading function output");
@@ -162,7 +162,7 @@ export function writeanotherMethodArgs(
 }
 
 export function deserializeanotherMethodResult(buffer: ArrayBuffer): i32 {
-  const context: Context =  new Context("Deserializing imported module-type: anotherMethod");
+  const context: Context = new Context("Deserializing imported module-type: anotherMethod");
   const reader = new ReadDecoder(buffer, context);
 
   reader.context().push("anotherMethod", "i32", "reading function output");
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/index.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/index.ts
index fc03152ed8..192e0901cc 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/index.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/index.ts
@@ -1,7 +1,7 @@
 import {
   Read,
   Write,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -26,9 +26,9 @@ export class TestImport_Object {
   objectArray: Array<Types.TestImport_AnotherObject>;
   optObjectArray: Array<Types.TestImport_AnotherObject | null> | null;
   en: Types.TestImport_Enum;
-  optEnum: Nullable<Types.TestImport_Enum>;
+  optEnum: Option<Types.TestImport_Enum>;
   enumArray: Array<Types.TestImport_Enum>;
-  optEnumArray: Array<Nullable<Types.TestImport_Enum>> | null;
+  optEnumArray: Array<Option<Types.TestImport_Enum>> | null;
 
   static toBuffer(type: TestImport_Object): ArrayBuffer {
     return serializeTestImport_Object(type);
diff --git a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/serialization.ts b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/serialization.ts
index 623dcdc2d5..9b588e9ca7 100644
--- a/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/serialization.ts
+++ b/packages/test-cases/cases/bind/sanity/output/wasm-as/imported/TestImport_Object/serialization.ts
@@ -4,7 +4,7 @@ import {
   Write,
   WriteSizer,
   WriteEncoder,
-  Nullable,
+  Option,
   BigInt,
   BigNumber,
   JSON,
@@ -58,7 +58,7 @@ export function writeTestImport_Object(writer: Write, type: TestImport_Object):
   writer.writeString("en");
   writer.writeInt32(type.en);
   writer.context().pop();
-  writer.context().push("optEnum", "Nullable<Types.TestImport_Enum>", "writing property");
+  writer.context().push("optEnum", "Option<Types.TestImport_Enum>", "writing property");
   writer.writeString("optEnum");
   writer.writeNullableInt32(type.optEnum);
   writer.context().pop();
@@ -68,9 +68,9 @@ export function writeTestImport_Object(writer: Write, type: TestImport_Object):
     writer.writeInt32(item);
   });
   writer.context().pop();
-  writer.context().push("optEnumArray", "Array<Nullable<Types.TestImport_Enum>> | null", "writing property");
+  writer.context().push("optEnumArray", "Array<Option<Types.TestImport_Enum>> | null", "writing property");
   writer.writeString("optEnumArray");
-  writer.writeNullableArray(type.optEnumArray, (writer: Write, item: Nullable<Types.TestImport_Enum>): void => {
+  writer.writeNullableArray(type.optEnumArray, (writer: Write, item: Option<Types.TestImport_Enum>): void => {
     writer.writeNullableInt32(item);
   });
   writer.context().pop();
@@ -93,10 +93,10 @@ export function readTestImport_Object(reader: Read): TestImport_Object {
   let _optObjectArray: Array<Types.TestImport_AnotherObject | null> | null = null;
   let _en: Types.TestImport_Enum = 0;
   let _enSet: bool = false;
-  let _optEnum: Nullable<Types.TestImport_Enum> = new Nullable<Types.TestImport_Enum>();
+  let _optEnum: Option<Types.TestImport_Enum> = Option.None<Types.TestImport_Enum>();
   let _enumArray: Array<Types.TestImport_Enum> = [];
   let _enumArraySet: bool = false;
-  let _optEnumArray: Array<Nullable<Types.TestImport_Enum>> | null = null;
+  let _optEnumArray: Array<Option<Types.TestImport_Enum>> | null = null;
 
   while (numFields > 0) {
     numFields--;
@@ -153,21 +153,21 @@ export function readTestImport_Object(reader: Read): TestImport_Object {
       reader.context().pop();
     }
     else if (field == "optEnum") {
-      reader.context().push(field, "Nullable<Types.TestImport_Enum>", "type found, reading property");
-      let value: Nullable<Types.TestImport_Enum>;
+      reader.context().push(field, "Option<Types.TestImport_Enum>", "type found, reading property");
+      let value: Option<Types.TestImport_Enum>;
       if (!reader.isNextNil()) {
         if (reader.isNextString()) {
-          value = Nullable.fromValue(
+          value = Option.Some(
             Types.getTestImport_EnumValue(reader.readString())
           );
         } else {
-          value = Nullable.fromValue(
+          value = Option.Some(
             reader.readInt32()
           );
-          Types.sanitizeTestImport_EnumValue(value.value);
+          Types.sanitizeTestImport_EnumValue(value.unwrap());
         }
       } else {
-        value = Nullable.fromNull<Types.TestImport_Enum>();
+        value = Option.None<Types.TestImport_Enum>();
       }
       _optEnum = value;
       reader.context().pop();
@@ -188,22 +188,22 @@ export function readTestImport_Object(reader: Read): TestImport_Object {
       reader.context().pop();
     }
     else if (field == "optEnumArray") {
-      reader.context().push(field, "Array<Nullable<Types.TestImport_Enum>> | null", "type found, reading property");
-      _optEnumArray = reader.readNullableArray((reader: Read): Nullable<Types.TestImport_Enum> => {
-        let value: Nullable<Types.TestImport_Enum>;
+      reader.context().push(field, "Array<Option<Types.TestImport_Enum>> | null", "type found, reading property");
+      _optEnumArray = reader.readNullableArray((reader: Read): Option<Types.TestImport_Enum> => {
+        let value: Option<Types.TestImport_Enum>;
         if (!reader.isNextNil()) {
           if (reader.isNextString()) {
-            value = Nullable.fromValue(
+            value = Option.Some(
               Types.getTestImport_EnumValue(reader.readString())
             );
           } else {
-            value = Nullable.fromValue(
+            value = Option.Some(
               reader.readInt32()
             );
-            Types.sanitizeTestImport_EnumValue(value.value);
+            Types.sanitizeTestImport_EnumValue(value.unwrap());
           }
         } else {
-          value = Nullable.fromNull<Types.TestImport_Enum>();
+          value = Option.None<Types.TestImport_Enum>();
         }
         return value;
       });
diff --git a/packages/wasm/as/assembly/__tests__/msgpack.spec.ts b/packages/wasm/as/assembly/__tests__/msgpack.spec.ts
index 44ccfdbcc7..e63ef0a802 100644
--- a/packages/wasm/as/assembly/__tests__/msgpack.spec.ts
+++ b/packages/wasm/as/assembly/__tests__/msgpack.spec.ts
@@ -1,7 +1,6 @@
 /* eslint-disable @typescript-eslint/no-inferrable-types */
 
 import {
-  Nullable,
   Read,
   ReadDecoder,
   Write,
@@ -11,6 +10,7 @@ import {
   BigInt,
   BigNumber,
 } from "../";
+import { Option } from "as-container";
 
 class Sanity {
   nil: string | null = "null";
@@ -21,8 +21,8 @@ class Sanity {
   uint16: u16;
   uint32: u32;
   boolean: bool;
-  optUint32: Nullable<u32> = new Nullable<u32>();
-  optBool: Nullable<bool> = new Nullable<bool>();
+  optUint32: Option<u32> = Option.None<u32>();
+  optBool: Option<bool> = Option.None<bool>();
   float32: f32;
   float64: f64;
   str: string = "";
@@ -49,8 +49,8 @@ class Sanity {
     this.uint16 = 65535;
     this.uint32 = 4294967295;
     this.boolean = true;
-    this.optUint32 = Nullable.fromValue<u32>(234234234);
-    this.optBool = Nullable.fromValue<bool>(true);
+    this.optUint32 = Option.Some<u32>(234234234);
+    this.optBool = Option.Some<bool>(true);
     this.float32 = 3.40282344818115234375;
     this.float64 = 3124124512.598273468017578125;
     this.str = "Hello, world!";
diff --git a/packages/wasm/as/assembly/__tests__/nullable.spec.ts b/packages/wasm/as/assembly/__tests__/nullable.spec.ts
deleted file mode 100644
index 424731136b..0000000000
--- a/packages/wasm/as/assembly/__tests__/nullable.spec.ts
+++ /dev/null
@@ -1,17 +0,0 @@
-import { Nullable } from "../msgpack/Nullable";
-
-describe("Nullable: Sanity", () => {
-  it("Works", () => {
-    const value = Nullable.fromValue<u64>(500);
-    const other = Nullable.fromNull<u64>();
-
-    expect(value.value).toBe(500);
-    expect(other).not.toBe(value);
-
-    expect(value == other).toBe(false);
-    expect(value != other).toBe(true);
-
-    const sameValue = Nullable.fromValue(value.value);
-    expect(sameValue == value).toBe(true);
-  });
-});
diff --git a/packages/wasm/as/assembly/index.ts b/packages/wasm/as/assembly/index.ts
index ffacda0174..372b974bd4 100644
--- a/packages/wasm/as/assembly/index.ts
+++ b/packages/wasm/as/assembly/index.ts
@@ -1,11 +1,5 @@
-export {
-  Read,
-  ReadDecoder,
-  Write,
-  WriteEncoder,
-  WriteSizer,
-  Nullable,
-} from "./msgpack";
+export { Option } from "as-container";
+export { Read, ReadDecoder, Write, WriteEncoder, WriteSizer } from "./msgpack";
 export * from "./json";
 export * from "./math";
 export * from "./containers";
diff --git a/packages/wasm/as/assembly/msgpack/Nullable.ts b/packages/wasm/as/assembly/msgpack/Nullable.ts
deleted file mode 100644
index 3165d50f07..0000000000
--- a/packages/wasm/as/assembly/msgpack/Nullable.ts
+++ /dev/null
@@ -1,55 +0,0 @@
-// Only class and string types can be
-// "nullable" using the `| null` notation.
-// Nullable<T> is used for nullable value types.
-// https://www.assemblyscript.org/types.html#type-rules
-export class Nullable<T> {
-  private _value: T;
-  private _nil: bool;
-
-  constructor() {
-    this.toNull();
-  }
-
-  static fromValue<T>(value: T): Nullable<T> {
-    const nullable = new Nullable<T>();
-    nullable.value = value;
-    return nullable;
-  }
-
-  static fromNull<T>(): Nullable<T> {
-    return new Nullable<T>();
-  }
-
-  get value(): T {
-    return this._value;
-  }
-
-  set value(arg: T) {
-    this._value = arg;
-    this._nil = false;
-  }
-
-  get isNull(): bool {
-    return this._nil;
-  }
-
-  toNull(): void {
-    this._nil = true;
-  }
-
-  @inline
-  @operator("==")
-  protected eq(rhs: Nullable<T>): bool {
-    if (this._nil) {
-      return this._nil == rhs._nil;
-    } else {
-      return !(rhs._nil || this._value != rhs._value);
-    }
-  }
-
-  @inline
-  @operator("!=")
-  protected neq(rhs: Nullable<T>): bool {
-    return !this.eq(rhs);
-  }
-}
diff --git a/packages/wasm/as/assembly/msgpack/Read.ts b/packages/wasm/as/assembly/msgpack/Read.ts
index 09517b9f0e..317623afbc 100644
--- a/packages/wasm/as/assembly/msgpack/Read.ts
+++ b/packages/wasm/as/assembly/msgpack/Read.ts
@@ -1,8 +1,9 @@
-import { Nullable } from "./Nullable";
 import { BigInt, BigNumber } from "../math";
 import { Context } from "../debug";
 import { JSON } from "../json";
 
+import { Option } from "as-container";
+
 export abstract class Read {
   abstract readBool(): bool;
   abstract readInt8(): i8;
@@ -32,15 +33,15 @@ export abstract class Read {
     value_fn: (reader: Read) => V
   ): Map<K, V>;
 
-  abstract readNullableBool(): Nullable<bool>;
-  abstract readNullableInt8(): Nullable<i8>;
-  abstract readNullableInt16(): Nullable<i16>;
-  abstract readNullableInt32(): Nullable<i32>;
-  abstract readNullableUInt8(): Nullable<u8>;
-  abstract readNullableUInt16(): Nullable<u16>;
-  abstract readNullableUInt32(): Nullable<u32>;
-  abstract readNullableFloat32(): Nullable<f32>;
-  abstract readNullableFloat64(): Nullable<f64>;
+  abstract readNullableBool(): Option<bool>;
+  abstract readNullableInt8(): Option<i8>;
+  abstract readNullableInt16(): Option<i16>;
+  abstract readNullableInt32(): Option<i32>;
+  abstract readNullableUInt8(): Option<u8>;
+  abstract readNullableUInt16(): Option<u16>;
+  abstract readNullableUInt32(): Option<u32>;
+  abstract readNullableFloat32(): Option<f32>;
+  abstract readNullableFloat64(): Option<f64>;
   abstract readNullableString(): string | null;
   abstract readNullableBytes(): ArrayBuffer | null;
   abstract readNullableBigInt(): BigInt | null;
diff --git a/packages/wasm/as/assembly/msgpack/ReadDecoder.ts b/packages/wasm/as/assembly/msgpack/ReadDecoder.ts
index f276810161..3a902eb81e 100644
--- a/packages/wasm/as/assembly/msgpack/ReadDecoder.ts
+++ b/packages/wasm/as/assembly/msgpack/ReadDecoder.ts
@@ -9,13 +9,14 @@ import {
   isFixedArray,
   isFixedString,
 } from "./Format";
-import { Nullable } from "./Nullable";
 import { Read } from "./Read";
 import { BigInt, BigNumber } from "../math";
 import { Context } from "../debug";
 import { JSON } from "../json";
 import { ExtensionType } from "./ExtensionType";
 
+import { Option } from "as-container";
+
 export class ReadDecoder extends Read {
   private readonly _context: Context;
   private _view: DataView;
@@ -363,67 +364,67 @@ export class ReadDecoder extends Read {
     return this.readMap(key_fn, value_fn);
   }
 
-  readNullableBool(): Nullable<bool> {
+  readNullableBool(): Option<bool> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<bool>();
+      return Option.None<bool>();
     }
-    return Nullable.fromValue<bool>(this.readBool());
+    return Option.Some<bool>(this.readBool());
   }
 
-  readNullableInt8(): Nullable<i8> {
+  readNullableInt8(): Option<i8> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<i8>();
+      return Option.None<i8>();
     }
-    return Nullable.fromValue<i8>(this.readInt8());
+    return Option.Some<i8>(this.readInt8());
   }
 
-  readNullableInt16(): Nullable<i16> {
+  readNullableInt16(): Option<i16> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<i16>();
+      return Option.None<i16>();
     }
-    return Nullable.fromValue<i16>(this.readInt16());
+    return Option.Some<i16>(this.readInt16());
   }
 
-  readNullableInt32(): Nullable<i32> {
+  readNullableInt32(): Option<i32> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<i32>();
+      return Option.None<i32>();
     }
-    return Nullable.fromValue<i32>(this.readInt32());
+    return Option.Some<i32>(this.readInt32());
   }
 
-  readNullableUInt8(): Nullable<u8> {
+  readNullableUInt8(): Option<u8> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<u8>();
+      return Option.None<u8>();
     }
-    return Nullable.fromValue<u8>(this.readUInt8());
+    return Option.Some<u8>(this.readUInt8());
   }
 
-  readNullableUInt16(): Nullable<u16> {
+  readNullableUInt16(): Option<u16> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<u16>();
+      return Option.None<u16>();
     }
-    return Nullable.fromValue<u16>(this.readUInt16());
+    return Option.Some<u16>(this.readUInt16());
   }
 
-  readNullableUInt32(): Nullable<u32> {
+  readNullableUInt32(): Option<u32> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<u32>();
+      return Option.None<u32>();
     }
-    return Nullable.fromValue<u32>(this.readUInt32());
+    return Option.Some<u32>(this.readUInt32());
   }
 
-  readNullableFloat32(): Nullable<f32> {
+  readNullableFloat32(): Option<f32> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<f32>();
+      return Option.None<f32>();
     }
-    return Nullable.fromValue<f32>(this.readFloat32());
+    return Option.Some<f32>(this.readFloat32());
   }
 
-  readNullableFloat64(): Nullable<f64> {
+  readNullableFloat64(): Option<f64> {
     if (this.isNextNil()) {
-      return Nullable.fromNull<f64>();
+      return Option.None<f64>();
     }
-    return Nullable.fromValue<f64>(this.readFloat64());
+    return Option.Some<f64>(this.readFloat64());
   }
 
   readNullableString(): string | null {
diff --git a/packages/wasm/as/assembly/msgpack/Write.ts b/packages/wasm/as/assembly/msgpack/Write.ts
index b02a9ebbbf..f7ff982686 100644
--- a/packages/wasm/as/assembly/msgpack/Write.ts
+++ b/packages/wasm/as/assembly/msgpack/Write.ts
@@ -1,8 +1,9 @@
-import { Nullable } from "./Nullable";
 import { BigInt, BigNumber } from "../math";
 import { Context } from "../debug";
 import { JSON } from "../json";
 
+import { Option } from "as-container";
+
 export abstract class Write {
   abstract writeNil(): void;
   abstract writeBool(value: bool): void;
@@ -38,15 +39,15 @@ export abstract class Write {
     value_fn: (writer: Write, value: V) => void
   ): void;
 
-  abstract writeNullableBool(value: Nullable<bool>): void;
-  abstract writeNullableInt8(value: Nullable<i8>): void;
-  abstract writeNullableInt16(value: Nullable<i16>): void;
-  abstract writeNullableInt32(value: Nullable<i32>): void;
-  abstract writeNullableUInt8(value: Nullable<u8>): void;
-  abstract writeNullableUInt16(value: Nullable<u16>): void;
-  abstract writeNullableUInt32(value: Nullable<u32>): void;
-  abstract writeNullableFloat32(value: Nullable<f32>): void;
-  abstract writeNullableFloat64(value: Nullable<f64>): void;
+  abstract writeNullableBool(value: Option<bool>): void;
+  abstract writeNullableInt8(value: Option<i8>): void;
+  abstract writeNullableInt16(value: Option<i16>): void;
+  abstract writeNullableInt32(value: Option<i32>): void;
+  abstract writeNullableUInt8(value: Option<u8>): void;
+  abstract writeNullableUInt16(value: Option<u16>): void;
+  abstract writeNullableUInt32(value: Option<u32>): void;
+  abstract writeNullableFloat32(value: Option<f32>): void;
+  abstract writeNullableFloat64(value: Option<f64>): void;
   abstract writeNullableString(value: string | null): void;
   abstract writeNullableBytes(value: ArrayBuffer | null): void;
   abstract writeNullableBigInt(value: BigInt | null): void;
diff --git a/packages/wasm/as/assembly/msgpack/WriteEncoder.ts b/packages/wasm/as/assembly/msgpack/WriteEncoder.ts
index 8763a348ed..02140973b5 100644
--- a/packages/wasm/as/assembly/msgpack/WriteEncoder.ts
+++ b/packages/wasm/as/assembly/msgpack/WriteEncoder.ts
@@ -2,13 +2,14 @@ import { DataView } from "./DataView";
 import { WriteSizer } from "./WriteSizer";
 import { Format } from "./Format";
 import { ExtensionType } from "./ExtensionType";
-import { Nullable } from "./Nullable";
 import { Write } from "./Write";
 import { throwArrayIndexOutOfRange } from "./utils";
 import { BigInt, BigNumber } from "../math";
 import { Context } from "../debug";
 import { JSON } from "../json";
 
+import { Option } from "as-container";
+
 export class WriteEncoder extends Write {
   private readonly _context: Context;
   private _view: DataView;
@@ -234,85 +235,85 @@ export class WriteEncoder extends Write {
     this.writeMap(m, key_fn, value_fn);
   }
 
-  writeNullableBool(value: Nullable<bool>): void {
-    if (value.isNull) {
+  writeNullableBool(value: Option<bool>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeBool(value.value);
+    this.writeBool(value.unwrap());
   }
 
-  writeNullableInt8(value: Nullable<i8>): void {
-    if (value.isNull) {
+  writeNullableInt8(value: Option<i8>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeInt8(value.value);
+    this.writeInt8(value.unwrap());
   }
 
-  writeNullableInt16(value: Nullable<i16>): void {
-    if (value.isNull) {
+  writeNullableInt16(value: Option<i16>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeInt16(value.value);
+    this.writeInt16(value.unwrap());
   }
 
-  writeNullableInt32(value: Nullable<i32>): void {
-    if (value.isNull) {
+  writeNullableInt32(value: Option<i32>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeInt32(value.value);
+    this.writeInt32(value.unwrap());
   }
 
-  writeNullableUInt8(value: Nullable<u8>): void {
-    if (value.isNull) {
+  writeNullableUInt8(value: Option<u8>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeUInt8(value.value);
+    this.writeUInt8(value.unwrap());
   }
 
-  writeNullableUInt16(value: Nullable<u16>): void {
-    if (value.isNull) {
+  writeNullableUInt16(value: Option<u16>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeUInt16(value.value);
+    this.writeUInt16(value.unwrap());
   }
 
-  writeNullableUInt32(value: Nullable<u32>): void {
-    if (value.isNull) {
+  writeNullableUInt32(value: Option<u32>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeUInt32(value.value);
+    this.writeUInt32(value.unwrap());
   }
 
-  writeNullableFloat32(value: Nullable<f32>): void {
-    if (value.isNull) {
+  writeNullableFloat32(value: Option<f32>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeFloat32(value.value);
+    this.writeFloat32(value.unwrap());
   }
 
-  writeNullableFloat64(value: Nullable<f64>): void {
-    if (value.isNull) {
+  writeNullableFloat64(value: Option<f64>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeFloat64(value.value);
+    this.writeFloat64(value.unwrap());
   }
 
   writeNullableString(value: string | null): void {
diff --git a/packages/wasm/as/assembly/msgpack/WriteSizer.ts b/packages/wasm/as/assembly/msgpack/WriteSizer.ts
index f88aaf639f..4b32fd07c9 100644
--- a/packages/wasm/as/assembly/msgpack/WriteSizer.ts
+++ b/packages/wasm/as/assembly/msgpack/WriteSizer.ts
@@ -1,9 +1,10 @@
 import { Write } from "./Write";
-import { Nullable } from "./Nullable";
 import { BigInt, BigNumber } from "../math";
 import { Context } from "../debug";
 import { JSON } from "../json";
 
+import { Option } from "as-container";
+
 export class WriteSizer extends Write {
   length: i32;
   extByteLengths: Array<u32>;
@@ -194,85 +195,85 @@ export class WriteSizer extends Write {
     this.extByteLengths.push(byteLength);
   }
 
-  writeNullableBool(value: Nullable<bool>): void {
-    if (value.isNull) {
+  writeNullableBool(value: Option<bool>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeBool(value.value);
+    this.writeBool(value.unwrap());
   }
 
-  writeNullableInt8(value: Nullable<i8>): void {
-    if (value.isNull) {
+  writeNullableInt8(value: Option<i8>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeInt8(value.value);
+    this.writeInt8(value.unwrap());
   }
 
-  writeNullableInt16(value: Nullable<i16>): void {
-    if (value.isNull) {
+  writeNullableInt16(value: Option<i16>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeInt16(value.value);
+    this.writeInt16(value.unwrap());
   }
 
-  writeNullableInt32(value: Nullable<i32>): void {
-    if (value.isNull) {
+  writeNullableInt32(value: Option<i32>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeInt32(value.value);
+    this.writeInt32(value.unwrap());
   }
 
-  writeNullableUInt8(value: Nullable<u8>): void {
-    if (value.isNull) {
+  writeNullableUInt8(value: Option<u8>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeUInt8(value.value);
+    this.writeUInt8(value.unwrap());
   }
 
-  writeNullableUInt16(value: Nullable<u16>): void {
-    if (value.isNull) {
+  writeNullableUInt16(value: Option<u16>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeUInt16(value.value);
+    this.writeUInt16(value.unwrap());
   }
 
-  writeNullableUInt32(value: Nullable<u32>): void {
-    if (value.isNull) {
+  writeNullableUInt32(value: Option<u32>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeUInt32(value.value);
+    this.writeUInt32(value.unwrap());
   }
 
-  writeNullableFloat32(value: Nullable<f32>): void {
-    if (value.isNull) {
+  writeNullableFloat32(value: Option<f32>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeFloat32(value.value);
+    this.writeFloat32(value.unwrap());
   }
 
-  writeNullableFloat64(value: Nullable<f64>): void {
-    if (value.isNull) {
+  writeNullableFloat64(value: Option<f64>): void {
+    if (value.isNone) {
       this.writeNil();
       return;
     }
 
-    this.writeFloat64(value.value);
+    this.writeFloat64(value.unwrap());
   }
 
   writeNullableString(value: string | null): void {
diff --git a/packages/wasm/as/assembly/msgpack/index.ts b/packages/wasm/as/assembly/msgpack/index.ts
index 1ed14b50e4..0f7d2c3630 100644
--- a/packages/wasm/as/assembly/msgpack/index.ts
+++ b/packages/wasm/as/assembly/msgpack/index.ts
@@ -3,4 +3,3 @@ export * from "./ReadDecoder";
 export * from "./Write";
 export * from "./WriteEncoder";
 export * from "./WriteSizer";
-export * from "./Nullable";