diff --git a/ejson/lib/src/decoding.dart b/ejson/lib/src/decoding.dart
index 16d740e755..e8ec688d07 100644
--- a/ejson/lib/src/decoding.dart
+++ b/ejson/lib/src/decoding.dart
@@ -22,7 +22,7 @@ const commonDecoders = {
   UndefinedOr: _decodeUndefinedOr,
 };
 
-var customDecoders = const <Type, Function>{};
+var customDecoders = <Type, Function>{};
 
 // if registerSerializableTypes not called
 final decoders = () {
diff --git a/ejson/lib/src/encoding.dart b/ejson/lib/src/encoding.dart
index 5ed9e38924..c2b861735e 100644
--- a/ejson/lib/src/encoding.dart
+++ b/ejson/lib/src/encoding.dart
@@ -3,7 +3,7 @@ import 'package:type_plus/type_plus.dart';
 import 'types.dart';
 
 // No custom encoders, if registerSerializableTypes not called
-var customEncoders = const <Type, Function>{};
+var customEncoders = <Type, Function>{};
 
 var relaxed = false;
 
diff --git a/ejson/lib/src/generator/generator.dart b/ejson/lib/src/generator/generator.dart
index beb60f5abb..8d347b9447 100644
--- a/ejson/lib/src/generator/generator.dart
+++ b/ejson/lib/src/generator/generator.dart
@@ -1,17 +1,59 @@
+import 'dart:async';
+
 import 'package:analyzer/dart/element/element.dart';
 import 'package:build/build.dart';
 import 'package:ejson/ejson.dart';
 import 'package:source_gen/source_gen.dart';
 
 /// @nodoc
-class EJsonGenerator extends GeneratorForAnnotation<EJson> {
+class EJsonGenerator extends Generator {
+  const EJsonGenerator();
+
+  TypeChecker get typeChecker => TypeChecker.fromRuntime(EJson);
+
   @override
-  String generateForAnnotatedElement(
-    Element element,
-    ConstantReader annotation,
-    BuildStep buildStep,
-  ) {
-    if (element is ConstructorElement) {}
-    return '';
+  FutureOr<String> generate(LibraryReader library, BuildStep buildStep) async {
+    final ctors = library.classes.map(
+      (c) => c.constructors.singleWhere(
+        (c) =>
+            typeChecker.firstAnnotationOf(c, throwOnUnresolved: false) != null,
+      ),
+    );
+    return ctors.map((ctor) {
+      final cls = ctor.enclosingElement;
+      final className = ctor.enclosingElement.name;
+
+      log.info('Generating EJson for $className');
+      return '''
+        EJsonValue encode$className($className value) {
+          return {
+            ${ctor.parameters.map((p) => "'${p.name}': value.${p.name}.toEJson()").join('\n')}
+          };
+        }
+
+        $className decode$className(EJsonValue ejson) {
+          return switch (ejson) {
+            ${decodePattern(ctor.parameters)} => $className(
+              ${ctor.parameters.map((p) => "${p.name}.to<${p.type}>()").join(',\n')}
+            ),
+            _ => raiseInvalidEJson(ejson),
+          };
+        }
+
+        extension ${className}EJsonEncoderExtension on $className {
+          @pragma('vm:prefer-inline')
+          EJsonValue toEJson() => encode$className(this);
+        }
+      ''';
+    }).join('\n\n');
+  }
+}
+
+String decodePattern(Iterable<ParameterElement> parameters) {
+  if (parameters.isEmpty) {
+    return 'Map m when m.isEmpty';
   }
+  return parameters
+      .map((p) => "{'${p.name}': EJsonValue ${p.name}}")
+      .join(',\n');
 }
diff --git a/ejson/pubspec.lock b/ejson/pubspec.lock
deleted file mode 100644
index 3027d11792..0000000000
--- a/ejson/pubspec.lock
+++ /dev/null
@@ -1,405 +0,0 @@
-# Generated by pub
-# See https://dart.dev/tools/pub/glossary#lockfile
-packages:
-  _fe_analyzer_shared:
-    dependency: transitive
-    description:
-      name: _fe_analyzer_shared
-      sha256: ae92f5d747aee634b87f89d9946000c2de774be1d6ac3e58268224348cd0101a
-      url: "https://pub.dev"
-    source: hosted
-    version: "61.0.0"
-  analyzer:
-    dependency: "direct main"
-    description:
-      name: analyzer
-      sha256: ea3d8652bda62982addfd92fdc2d0214e5f82e43325104990d4f4c4a2a313562
-      url: "https://pub.dev"
-    source: hosted
-    version: "5.13.0"
-  args:
-    dependency: transitive
-    description:
-      name: args
-      sha256: c372bb384f273f0c2a8aaaa226dad84dc27c8519a691b888725dec59518ad53a
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.4.1"
-  async:
-    dependency: transitive
-    description:
-      name: async
-      sha256: "947bfcf187f74dbc5e146c9eb9c0f10c9f8b30743e341481c1e2ed3ecc18c20c"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.11.0"
-  boolean_selector:
-    dependency: transitive
-    description:
-      name: boolean_selector
-      sha256: "6cfb5af12253eaf2b368f07bacc5a80d1301a071c73360d746b7f2e32d762c66"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.1"
-  build:
-    dependency: "direct main"
-    description:
-      name: build
-      sha256: "43865b79fbb78532e4bff7c33087aa43b1d488c4fdef014eaef568af6d8016dc"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.4.0"
-  collection:
-    dependency: "direct main"
-    description:
-      name: collection
-      sha256: f092b211a4319e98e5ff58223576de6c2803db36221657b46c82574721240687
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.17.2"
-  convert:
-    dependency: transitive
-    description:
-      name: convert
-      sha256: "0f08b14755d163f6e2134cb58222dd25ea2a2ee8a195e53983d57c075324d592"
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.1.1"
-  coverage:
-    dependency: transitive
-    description:
-      name: coverage
-      sha256: "2fb815080e44a09b85e0f2ca8a820b15053982b2e714b59267719e8a9ff17097"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.6.3"
-  crypto:
-    dependency: transitive
-    description:
-      name: crypto
-      sha256: ff625774173754681d66daaf4a448684fb04b78f902da9cb3d308c19cc5e8bab
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.0.3"
-  dart_style:
-    dependency: transitive
-    description:
-      name: dart_style
-      sha256: f4f1f73ab3fd2afcbcca165ee601fe980d966af6a21b5970c6c9376955c528ad
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.3.1"
-  file:
-    dependency: transitive
-    description:
-      name: file
-      sha256: "5fc22d7c25582e38ad9a8515372cd9a93834027aacf1801cf01164dac0ffa08c"
-      url: "https://pub.dev"
-    source: hosted
-    version: "7.0.0"
-  frontend_server_client:
-    dependency: transitive
-    description:
-      name: frontend_server_client
-      sha256: "408e3ca148b31c20282ad6f37ebfa6f4bdc8fede5b74bc2f08d9d92b55db3612"
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.2.0"
-  glob:
-    dependency: transitive
-    description:
-      name: glob
-      sha256: "0e7014b3b7d4dac1ca4d6114f82bf1782ee86745b9b42a92c9289c23d8a0ab63"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.2"
-  http_multi_server:
-    dependency: transitive
-    description:
-      name: http_multi_server
-      sha256: "97486f20f9c2f7be8f514851703d0119c3596d14ea63227af6f7a481ef2b2f8b"
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.2.1"
-  http_parser:
-    dependency: transitive
-    description:
-      name: http_parser
-      sha256: "2aa08ce0341cc9b354a498388e30986515406668dbcc4f7c950c3e715496693b"
-      url: "https://pub.dev"
-    source: hosted
-    version: "4.0.2"
-  io:
-    dependency: transitive
-    description:
-      name: io
-      sha256: "2ec25704aba361659e10e3e5f5d672068d332fc8ac516421d483a11e5cbd061e"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.0.4"
-  js:
-    dependency: transitive
-    description:
-      name: js
-      sha256: f2c445dce49627136094980615a031419f7f3eb393237e4ecd97ac15dea343f3
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.6.7"
-  lints:
-    dependency: "direct dev"
-    description:
-      name: lints
-      sha256: "6b0206b0bf4f04961fc5438198ccb3a885685cd67d4d4a32cc20ad7f8adbe015"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.0"
-  logging:
-    dependency: transitive
-    description:
-      name: logging
-      sha256: "623a88c9594aa774443aa3eb2d41807a48486b5613e67599fb4c41c0ad47c340"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.2.0"
-  matcher:
-    dependency: transitive
-    description:
-      name: matcher
-      sha256: "1803e76e6653768d64ed8ff2e1e67bea3ad4b923eb5c56a295c3e634bad5960e"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.12.16"
-  meta:
-    dependency: transitive
-    description:
-      name: meta
-      sha256: "3c74dbf8763d36539f114c799d8a2d87343b5067e9d796ca22b5eb8437090ee3"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.9.1"
-  mime:
-    dependency: transitive
-    description:
-      name: mime
-      sha256: e4ff8e8564c03f255408decd16e7899da1733852a9110a58fe6d1b817684a63e
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.0.4"
-  node_preamble:
-    dependency: transitive
-    description:
-      name: node_preamble
-      sha256: "6e7eac89047ab8a8d26cf16127b5ed26de65209847630400f9aefd7cd5c730db"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.0.2"
-  package_config:
-    dependency: transitive
-    description:
-      name: package_config
-      sha256: "1c5b77ccc91e4823a5af61ee74e6b972db1ef98c2ff5a18d3161c982a55448bd"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.0"
-  path:
-    dependency: transitive
-    description:
-      name: path
-      sha256: "8829d8a55c13fc0e37127c29fedf290c102f4e40ae94ada574091fe0ff96c917"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.8.3"
-  pool:
-    dependency: transitive
-    description:
-      name: pool
-      sha256: "20fe868b6314b322ea036ba325e6fc0711a22948856475e2c2b6306e8ab39c2a"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.5.1"
-  pub_semver:
-    dependency: transitive
-    description:
-      name: pub_semver
-      sha256: "40d3ab1bbd474c4c2328c91e3a7df8c6dd629b79ece4c4bd04bee496a224fb0c"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.4"
-  shelf:
-    dependency: transitive
-    description:
-      name: shelf
-      sha256: ad29c505aee705f41a4d8963641f91ac4cee3c8fad5947e033390a7bd8180fa4
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.4.1"
-  shelf_packages_handler:
-    dependency: transitive
-    description:
-      name: shelf_packages_handler
-      sha256: "89f967eca29607c933ba9571d838be31d67f53f6e4ee15147d5dc2934fee1b1e"
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.0.2"
-  shelf_static:
-    dependency: transitive
-    description:
-      name: shelf_static
-      sha256: a41d3f53c4adf0f57480578c1d61d90342cd617de7fc8077b1304643c2d85c1e
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.1.2"
-  shelf_web_socket:
-    dependency: transitive
-    description:
-      name: shelf_web_socket
-      sha256: "9ca081be41c60190ebcb4766b2486a7d50261db7bd0f5d9615f2d653637a84c1"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.0.4"
-  source_gen:
-    dependency: "direct main"
-    description:
-      name: source_gen
-      sha256: "373f96cf5a8744bc9816c1ff41cf5391bbdbe3d7a96fe98c622b6738a8a7bd33"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.3.2"
-  source_map_stack_trace:
-    dependency: transitive
-    description:
-      name: source_map_stack_trace
-      sha256: "84cf769ad83aa6bb61e0aa5a18e53aea683395f196a6f39c4c881fb90ed4f7ae"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.1"
-  source_maps:
-    dependency: transitive
-    description:
-      name: source_maps
-      sha256: "708b3f6b97248e5781f493b765c3337db11c5d2c81c3094f10904bfa8004c703"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.10.12"
-  source_span:
-    dependency: transitive
-    description:
-      name: source_span
-      sha256: "53e943d4206a5e30df338fd4c6e7a077e02254531b138a15aec3bd143c1a8b3c"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.10.0"
-  stack_trace:
-    dependency: transitive
-    description:
-      name: stack_trace
-      sha256: c3c7d8edb15bee7f0f74debd4b9c5f3c2ea86766fe4178eb2a18eb30a0bdaed5
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.11.0"
-  stream_channel:
-    dependency: transitive
-    description:
-      name: stream_channel
-      sha256: "83615bee9045c1d322bbbd1ba209b7a749c2cbcdcb3fdd1df8eb488b3279c1c8"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.1"
-  string_scanner:
-    dependency: transitive
-    description:
-      name: string_scanner
-      sha256: "556692adab6cfa87322a115640c11f13cb77b3f076ddcc5d6ae3c20242bedcde"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.2.0"
-  term_glyph:
-    dependency: transitive
-    description:
-      name: term_glyph
-      sha256: a29248a84fbb7c79282b40b8c72a1209db169a2e0542bce341da992fe1bc7e84
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.2.1"
-  test:
-    dependency: "direct dev"
-    description:
-      name: test
-      sha256: "13b41f318e2a5751c3169137103b60c584297353d4b1761b66029bae6411fe46"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.24.3"
-  test_api:
-    dependency: transitive
-    description:
-      name: test_api
-      sha256: "75760ffd7786fffdfb9597c35c5b27eaeec82be8edfb6d71d32651128ed7aab8"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.6.0"
-  test_core:
-    dependency: transitive
-    description:
-      name: test_core
-      sha256: "99806e9e6d95c7b059b7a0fc08f07fc53fabe54a829497f0d9676299f1e8637e"
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.5.3"
-  type_plus:
-    dependency: "direct main"
-    description:
-      name: type_plus
-      sha256: "28cbdcb9d2118f65881d11158ecb4d9db8b78589969e3168061d06963ef3ca59"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.0.0"
-  typed_data:
-    dependency: transitive
-    description:
-      name: typed_data
-      sha256: facc8d6582f16042dd49f2463ff1bd6e2c9ef9f3d5da3d9b087e244a7b564b3c
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.3.2"
-  vm_service:
-    dependency: transitive
-    description:
-      name: vm_service
-      sha256: f3743ca475e0c9ef71df4ba15eb2d7684eecd5c8ba20a462462e4e8b561b2e11
-      url: "https://pub.dev"
-    source: hosted
-    version: "11.6.0"
-  watcher:
-    dependency: transitive
-    description:
-      name: watcher
-      sha256: "3d2ad6751b3c16cf07c7fca317a1413b3f26530319181b37e3b9039b84fc01d8"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.1.0"
-  web_socket_channel:
-    dependency: transitive
-    description:
-      name: web_socket_channel
-      sha256: d88238e5eac9a42bb43ca4e721edba3c08c6354d4a53063afaa568516217621b
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.4.0"
-  webkit_inspection_protocol:
-    dependency: transitive
-    description:
-      name: webkit_inspection_protocol
-      sha256: "67d3a8b6c79e1987d19d848b0892e582dbb0c66c57cc1fef58a177dd2aa2823d"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.2.0"
-  yaml:
-    dependency: transitive
-    description:
-      name: yaml
-      sha256: "75769501ea3489fca56601ff33454fe45507ea3bfb014161abc3b43ae25989d5"
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.1.2"
-sdks:
-  dart: ">=3.0.1 <4.0.0"