diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
deleted file mode 100644
index 5c6a502..0000000
--- a/.devcontainer/devcontainer.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-  "image": "mcr.microsoft.com/devcontainers/universal:2",
-  "features": {
-    "ghcr.io/devcontainers-extra/features/sbt-sdkman:2": {}
-  },
-  "postCreateCommand": "sdk install sbt"
-}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9208c3f..1a53cd4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,14 +13,13 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - uses: coursier/cache-action@v6
-      - uses: VirtusLab/scala-cli-setup@main
+      - uses: actions/setup-java@v4
         with:
-          jvm: temurin:21
-          apps: sbt
-          power: true
+          java-version: 25
+          distribution: temurin
       - name: Start up emulators
-        run: docker compose up -d 
-      - run: sbt buildCliBinary test
+        run: docker compose up -d
+      - run: ./mill tests.__.test
   publish:
     runs-on: ubuntu-latest
     name: Publish Artifacts
@@ -29,17 +28,16 @@ jobs:
     steps:
       - uses: actions/checkout@v5
       - uses: coursier/cache-action@v6
-      - uses: VirtusLab/scala-cli-setup@main
+      - uses: actions/setup-java@v4
         with:
-          jvm: temurin:21
-          apps: sbt
+          java-version: 25
+          distribution: temurin
       - name: Import signing key
         if: env.PGP_SECRET != '' && env.PGP_PASSPHRASE == ''
         env:
           PGP_SECRET: ${{ secrets.PGP_SECRET }}
           PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}
         run: echo $PGP_SECRET | base64 -d -i - | gpg --import
-
       - name: Import signing key and strip passphrase
         if: env.PGP_SECRET != '' && env.PGP_PASSPHRASE != ''
         env:
@@ -53,4 +51,8 @@ jobs:
         env:
           SONATYPE_USERNAME: ${{ secrets.SONATYPE_USERNAME }}
           SONATYPE_PASSWORD: ${{ secrets.SONATYPE_PASSWORD }}
-        run: sbt publishSigned sonaRelease
+          PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}
+        run: |
+          ./mill core.jvm.publish
+          ./mill core.native.publish
+          ./mill cli.publish
diff --git a/.mill-version b/.mill-version
new file mode 100644
index 0000000..0664a8f
--- /dev/null
+++ b/.mill-version
@@ -0,0 +1 @@
+1.1.6
diff --git a/README.md b/README.md
index 0487752..2bf491b 100644
--- a/README.md
+++ b/README.md
@@ -67,7 +67,7 @@ See output in `example/out`.
 ##### Jsoniter Json type and codec example
 Jsoniter doesn't ship with a type that can represent raw Json values to be used for mapping of `any` / `object` types,  
 but it provides methods to read / write raw values as bytes (related [issue](https://github.com/plokhotnyuk/jsoniter-scala/issues/1257)).  
-Given that we can create a custom type with a codec which can look for example like [that](modules/example-jsoniter-json/shared/src/main/scala/json.scala):
+Given that we can create a custom type with a codec which can look for example like [that](modules/example-jsoniter-json/src/main/scala/json.scala):
 ```scala
 package example.jsoniter
 import com.github.plokhotnyuk.jsoniter_scala.core.*
diff --git a/build.mill b/build.mill
new file mode 100644
index 0000000..4ab4c3c
--- /dev/null
+++ b/build.mill
@@ -0,0 +1,222 @@
+package build
+
+import mill.*
+import mill.scalalib.*
+import mill.scalanativelib.*
+import mill.scalanativelib.api.*
+import mill.scalalib.publish.*
+import mill.util.VcsVersionModule
+import mill.api.Task.Simple
+import mill.api.TaskCtx
+import os.Path
+
+val scalaVer = "3.8.3"
+
+val scalaNativeVer = "0.5.12"
+
+val sttpClient4Ver = "4.0.23"
+
+val zioVer = "2.1.26"
+
+val zioJsonVer = "0.9.1"
+
+val jsoniterVer = "2.38.12"
+
+val munitVer = "1.3.0"
+
+val upickleVer = "4.4.3"
+
+/** Build the Scala Native CLI binary */
+def buildCliBinary: T[PathRef] = Task {
+  val linked = cli.nativeLink()
+  val dest = Task.dest / "cli"
+  os.makeDir.all(dest / os.up)
+  os.copy.over(linked.path, dest)
+  PathRef(dest)
+}
+
+trait Publishable extends PublishModule with VcsVersionModule {
+  def pomSettings = PomSettings(
+    description = "Google Cloud client code generator",
+    organization = "dev.rolang",
+    url = "https://github.com/rolang/google-rest-api-codegen",
+    licenses = Seq(License.MIT),
+    versionControl = VersionControl.github("rolang", "google-rest-api-codegen"),
+    developers = Seq(
+      Developer(id = "rolang", name = "Roman Langolf", url = "https://rolang.dev", email = "rolang@pm.me")
+    )
+  )
+}
+
+// ---------------------------------------------------------------------------
+// core: published as gcp-codegen, JVM + Scala Native
+// ---------------------------------------------------------------------------
+
+object core extends Module {
+  // jvm and native share src via SbtModule's parent-dir convention:
+  //   <moduleDir>/jvm/../src/main/scala == <moduleDir>/src/main/scala
+
+  trait CoreModule extends ScalaModule with SbtModule with Publishable {
+    override def moduleDir: Path = super.moduleDir / ".." / ".." / "modules" / "core"
+
+    def scalaVersion = scalaVer
+    override def artifactName = Task { "gcp-codegen" }
+    override def mvnDeps = Task { Seq(mvn"com.lihaoyi::upickle::$upickleVer") }
+  }
+
+  object jvm extends CoreModule
+
+  object native extends CoreModule with ScalaNativeModule {
+    def scalaNativeVersion = scalaNativeVer
+    override def nativeMultithreading: T[Option[Boolean]] = Task { Some(false) }
+  }
+}
+
+// ---------------------------------------------------------------------------
+// cli: published as gcp-codegen-cli, Scala Native binary
+// ---------------------------------------------------------------------------
+
+object cli extends ScalaNativeModule with Publishable with SbtModule {
+  override def moduleDir: Path = super.moduleDir / ".." / "modules" / "cli"
+  def scalaVersion = scalaVer
+  def scalaNativeVersion = scalaNativeVer
+  override def moduleDeps = Seq(core.native)
+  override def artifactName = Task { "gcp-codegen-cli" }
+  override def nativeMultithreading: T[Option[Boolean]] = Task { Some(false) }
+  override def releaseMode: T[ReleaseMode] = Task { ReleaseMode.ReleaseFast }
+}
+
+// ---------------------------------------------------------------------------
+// example-jsoniter-json: not published, JVM + Scala Native
+// ---------------------------------------------------------------------------
+
+object exampleJsoniterJson extends Module {
+  trait ExampleModule extends ScalaModule with SbtModule {
+    override def moduleDir: Path = super.moduleDir / ".." / ".." / "modules" / "example-jsoniter-json"
+    def scalaVersion = scalaVer
+    override def mvnDeps = Task { Seq(mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-core:$jsoniterVer") }
+    override def compileMvnDeps = Task {
+      Seq(mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-macros:$jsoniterVer")
+    }
+  }
+
+  object jvm extends ExampleModule
+
+  object native extends ExampleModule with ScalaNativeModule {
+    def scalaNativeVersion = scalaNativeVer
+  }
+}
+
+// ---------------------------------------------------------------------------
+// testLocal: local dev helper, not published
+// ---------------------------------------------------------------------------
+
+object testLocal extends ScalaModule {
+    override def sources = Task.Sources(moduleDir / "src" / "main" / "scala")
+  def scalaVersion = scalaVer
+  override def moduleDeps = Seq(exampleJsoniterJson.jvm)
+  override def mvnDeps = Task {
+    Seq(
+      mvn"com.softwaremill.sttp.client4::core:$sttpClient4Ver",
+      mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-core:$jsoniterVer",
+      mvn"dev.zio::zio-json:$zioJsonVer",
+      mvn"dev.zio::zio:$zioVer"
+    )
+  }
+  override def compileMvnDeps = Task {
+    Seq(mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-macros:$jsoniterVer")
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Test modules: one per (api, version, httpSource, jsonCodec, arrayType) combo
+// ---------------------------------------------------------------------------
+
+type TestKey = (String, String, String, String, String)
+
+val testCombos: Seq[TestKey] = for {
+  (apiName, apiVersion) <- Seq(
+    "pubsub" -> "v1",
+    "storage" -> "v1",
+    "aiplatform" -> "v1",
+    "iamcredentials" -> "v1",
+    "redis" -> "v1",
+    "sheets" -> "v4"
+  )
+  httpSource <- Seq("Sttp4")
+  jsonCodec <- Seq("ZioJson", "Jsoniter")
+  arrayType <- Seq("ZioChunk", "List")
+} yield (apiName, apiVersion, httpSource, jsonCodec, arrayType)
+
+object tests extends Cross[TestModule](testCombos)
+trait TestModule extends Cross.Module5[String, String, String, String, String] with ScalaModule {
+  val apiName = crossValue
+  val apiVersion = crossValue2
+  val httpSource = crossValue3
+  val jsonCodec = crossValue4
+  val arrayType = crossValue5
+
+  def scalaVersion = scalaVer
+
+  override def scalacOptions: T[Seq[String]] =
+    Task { super.scalacOptions() ++ Seq("-Xmax-inlines:64") }
+
+  override def sources: T[Seq[PathRef]] = Task { Seq.empty[PathRef] }
+
+  override def moduleDeps: Seq[JavaModule] =
+    if (jsonCodec == "Jsoniter") Seq(exampleJsoniterJson.jvm) else Seq()
+
+  override def mvnDeps: T[Seq[Dep]] = Task {
+    Seq(mvn"com.softwaremill.sttp.client4::core:$sttpClient4Ver") ++
+      (jsonCodec match {
+        case "Jsoniter" =>
+          Seq(mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-core:$jsoniterVer")
+        case "ZioJson" => Seq(mvn"dev.zio::zio-json:$zioJsonVer")
+        case other     => sys.error(s"Unknown jsonCodec: $other")
+      }) ++
+      (arrayType match {
+        case "ZioChunk" => Seq(mvn"dev.zio::zio:$zioVer")
+        case _          => Seq.empty
+      })
+  }
+
+  override def compileMvnDeps: T[Seq[Dep]] = Task {
+    if (jsonCodec == "Jsoniter")
+      Seq(mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-macros:$jsoniterVer")
+    else Seq.empty
+  }
+
+  override def generatedSources: T[Seq[PathRef]] = Task {
+    val dest = Task.dest
+    val basePkg = s"gcp.$apiName.$apiVersion.${httpSource}_${jsonCodec}_${arrayType}".toLowerCase()
+    val outSrcDir = dest / "scala"
+    val ws = implicitly[TaskCtx].workspace
+    val specFile =
+      ws / "modules" / "test-resources" / "src" / "main" / "resources" / s"${apiName}_${apiVersion}.json"
+
+    val cliBin = buildCliBinary()
+
+    os.makeDir.all(outSrcDir)
+    os.proc(
+      cliBin.path,
+      s"-specs=$specFile",
+      s"-out-dir=$outSrcDir",
+      s"-out-pkg=$basePkg",
+      s"-http-source=$httpSource",
+      s"-json-codec=$jsonCodec",
+      s"-array-type=$arrayType",
+      s"-jsoniter-json-type=_root_.example.jsoniter.Json"
+    ).call(cwd = ws)
+    Seq(PathRef(dest))
+  }
+
+  object test extends ScalaTests {
+    override def mvnDeps: T[Seq[Dep]] = Task {
+      Seq(
+        mvn"org.scalameta::munit:$munitVer",
+        mvn"com.github.plokhotnyuk.jsoniter-scala::jsoniter-scala-macros:$jsoniterVer"
+      )
+    }
+    def testFramework = "munit.Framework"
+  }
+}
diff --git a/mill b/mill
new file mode 100755
index 0000000..5268dce
--- /dev/null
+++ b/mill
@@ -0,0 +1,199 @@
+#!/usr/bin/env sh
+
+set -e
+
+if [ -z "${DEFAULT_MILL_VERSION}" ] ; then DEFAULT_MILL_VERSION="1.1.6"; fi
+
+if [ -z "${GITHUB_RELEASE_CDN}" ] ; then GITHUB_RELEASE_CDN=""; fi
+
+if [ -z "$MILL_MAIN_CLI" ] ; then MILL_MAIN_CLI="${0}"; fi
+
+MILL_REPO_URL="https://github.com/com-lihaoyi/mill"
+
+MILL_BUILD_SCRIPT=""
+
+if [ -f "build.mill" ] ; then
+  MILL_BUILD_SCRIPT="build.mill"
+elif [ -f "build.mill.scala" ] ; then
+  MILL_BUILD_SCRIPT="build.mill.scala"
+elif [ -f "build.sc" ] ; then
+  MILL_BUILD_SCRIPT="build.sc"
+fi
+
+# `s/.*://`:
+#   This is a greedy match that removes everything from the beginning of the line up to (and including) the last
+#   colon (:). This effectively isolates the value part of the declaration.
+#
+#  `s/#.*//`:
+#    This removes any comments at the end of the line.
+#
+#  `s/['\"]//g`:
+#    This removes all single and double quotes from the string, wherever they appear (g is for "global").
+#
+#  `s/^[[:space:]]*//; s/[[:space:]]*$//`:
+#    These two expressions trim any leading or trailing whitespace ([[:space:]] matches spaces and tabs).
+TRIM_VALUE_SED="s/.*://; s/#.*//; s/['\"]//g; s/^[[:space:]]*//; s/[[:space:]]*$//"
+
+if [ -z "${MILL_VERSION}" ] ; then
+  if [ -f ".mill-version" ] ; then
+    MILL_VERSION="$(tr '\r' '\n' < .mill-version | head -n 1 2> /dev/null)"
+  elif [ -f ".config/mill-version" ] ; then
+    MILL_VERSION="$(tr '\r' '\n' < .config/mill-version | head -n 1 2> /dev/null)"
+  elif [ -f "build.mill.yaml" ] ; then
+    MILL_VERSION="$(grep -E "mill-version:" "build.mill.yaml" | sed -E "$TRIM_VALUE_SED")"
+  elif [ -n "${MILL_BUILD_SCRIPT}" ] ; then
+    MILL_VERSION="$(grep -E "//\|.*mill-version" "${MILL_BUILD_SCRIPT}" | sed -E "$TRIM_VALUE_SED")"
+  fi
+fi
+
+if [ -z "${MILL_VERSION}" ] ; then MILL_VERSION="${DEFAULT_MILL_VERSION}"; fi
+
+MILL_USER_CACHE_DIR="${XDG_CACHE_HOME:-${HOME}/.cache}/mill"
+
+if [ -z "${MILL_FINAL_DOWNLOAD_FOLDER}" ] ; then MILL_FINAL_DOWNLOAD_FOLDER="${MILL_USER_CACHE_DIR}/download"; fi
+
+MILL_NATIVE_SUFFIX="-native"
+MILL_JVM_SUFFIX="-jvm"
+ARTIFACT_SUFFIX=""
+
+# Check if GLIBC version is at least the required version
+# Returns 0 (true) if GLIBC >= required version, 1 (false) otherwise
+check_glibc_version() {
+  required_version="2.39"
+  required_major=$(echo "$required_version" | cut -d. -f1)
+  required_minor=$(echo "$required_version" | cut -d. -f2)
+  # Get GLIBC version from ldd --version (first line contains version like "ldd (GNU libc) 2.31")
+  glibc_version=$(ldd --version 2>/dev/null | head -n 1 | grep -oE '[0-9]+\.[0-9]+$' || echo "")
+  if [ -z "$glibc_version" ]; then
+    # If we can't determine GLIBC version, assume it's too old
+    return 1
+  fi
+  glibc_major=$(echo "$glibc_version" | cut -d. -f1)
+  glibc_minor=$(echo "$glibc_version" | cut -d. -f2)
+  if [ "$glibc_major" -gt "$required_major" ]; then
+    return 0
+  elif [ "$glibc_major" -eq "$required_major" ] && [ "$glibc_minor" -ge "$required_minor" ]; then
+    return 0
+  else
+    return 1
+  fi
+}
+
+set_artifact_suffix() {
+  if [ "$(uname -s 2>/dev/null | cut -c 1-5)" = "Linux" ]; then
+    # Native binaries require new enough GLIBC; fall back to JVM launcher if older
+    if ! check_glibc_version; then
+      return
+    fi
+    if [ "$(uname -m)" = "aarch64" ]; then ARTIFACT_SUFFIX="-native-linux-aarch64"
+    else ARTIFACT_SUFFIX="-native-linux-amd64"; fi
+  elif [ "$(uname)" = "Darwin" ]; then
+    if [ "$(uname -m)" = "arm64" ]; then ARTIFACT_SUFFIX="-native-mac-aarch64"
+    else ARTIFACT_SUFFIX="-native-mac-amd64"; fi
+  else
+    echo "This native mill launcher supports only Linux and macOS." 1>&2
+    exit 1
+  fi
+}
+
+case "$MILL_VERSION" in
+  *"$MILL_NATIVE_SUFFIX")
+    MILL_VERSION=${MILL_VERSION%"$MILL_NATIVE_SUFFIX"}
+    set_artifact_suffix
+    ;;
+
+  *"$MILL_JVM_SUFFIX")
+    MILL_VERSION=${MILL_VERSION%"$MILL_JVM_SUFFIX"}
+    ;;
+
+  *)
+    case "$MILL_VERSION" in
+      0.1.* | 0.2.* | 0.3.* | 0.4.* | 0.5.* | 0.6.* | 0.7.* | 0.8.* | 0.9.* | 0.10.* | 0.11.* | 0.12.*)
+        ;;
+      *)
+        set_artifact_suffix
+        ;;
+    esac
+    ;;
+esac
+
+MILL="${MILL_FINAL_DOWNLOAD_FOLDER}/$MILL_VERSION$ARTIFACT_SUFFIX"
+
+# If not already downloaded, download it
+if [ ! -s "${MILL}" ] || [ "$MILL_TEST_DRY_RUN_LAUNCHER_SCRIPT" = "1" ] ; then
+  case $MILL_VERSION in
+    0.0.* | 0.1.* | 0.2.* | 0.3.* | 0.4.*)
+      MILL_DOWNLOAD_SUFFIX=""
+      MILL_DOWNLOAD_FROM_MAVEN=0
+      ;;
+    0.5.* | 0.6.* | 0.7.* | 0.8.* | 0.9.* | 0.10.* | 0.11.0-M*)
+      MILL_DOWNLOAD_SUFFIX="-assembly"
+      MILL_DOWNLOAD_FROM_MAVEN=0
+      ;;
+    *)
+      MILL_DOWNLOAD_SUFFIX="-assembly"
+      MILL_DOWNLOAD_FROM_MAVEN=1
+      ;;
+  esac
+  case $MILL_VERSION in
+    0.12.0 | 0.12.1 | 0.12.2 | 0.12.3 | 0.12.4 | 0.12.5 | 0.12.6 | 0.12.7 | 0.12.8 | 0.12.9 | 0.12.10 | 0.12.11)
+      MILL_DOWNLOAD_EXT="jar"
+      ;;
+    0.12.*)
+      MILL_DOWNLOAD_EXT="exe"
+      ;;
+    0.*)
+      MILL_DOWNLOAD_EXT="jar"
+      ;;
+    *)
+      MILL_DOWNLOAD_EXT="exe"
+      ;;
+  esac
+
+  MILL_TEMP_DOWNLOAD_FILE="${MILL_OUTPUT_DIR:-out}/mill-temp-download"
+  mkdir -p "$(dirname "${MILL_TEMP_DOWNLOAD_FILE}")"
+
+  if [ "$MILL_DOWNLOAD_FROM_MAVEN" = "1" ] ; then
+    MILL_DOWNLOAD_URL="https://repo1.maven.org/maven2/com/lihaoyi/mill-dist${ARTIFACT_SUFFIX}/${MILL_VERSION}/mill-dist${ARTIFACT_SUFFIX}-${MILL_VERSION}.${MILL_DOWNLOAD_EXT}"
+  else
+    MILL_VERSION_TAG=$(echo "$MILL_VERSION" | sed -E 's/([^-]+)(-M[0-9]+)?(-.*)?/\1\2/')
+    MILL_DOWNLOAD_URL="${GITHUB_RELEASE_CDN}${MILL_REPO_URL}/releases/download/${MILL_VERSION_TAG}/${MILL_VERSION}${MILL_DOWNLOAD_SUFFIX}"
+    unset MILL_VERSION_TAG
+  fi
+
+
+  if [ "$MILL_TEST_DRY_RUN_LAUNCHER_SCRIPT" = "1" ] ; then
+    echo "$MILL_DOWNLOAD_URL"
+    echo "$MILL"
+    exit 0
+  fi
+
+  echo "Downloading mill ${MILL_VERSION} from ${MILL_DOWNLOAD_URL} ..." 1>&2
+  curl -f -L -o "${MILL_TEMP_DOWNLOAD_FILE}" "${MILL_DOWNLOAD_URL}"
+
+  chmod +x "${MILL_TEMP_DOWNLOAD_FILE}"
+
+  mkdir -p "${MILL_FINAL_DOWNLOAD_FOLDER}"
+  mv "${MILL_TEMP_DOWNLOAD_FILE}" "${MILL}"
+
+  unset MILL_TEMP_DOWNLOAD_FILE
+  unset MILL_DOWNLOAD_SUFFIX
+fi
+
+MILL_FIRST_ARG=""
+if [ "$1" = "--bsp" ] || [ "${1#"-i"}" != "$1" ] || [ "$1" = "--interactive" ] || [ "$1" = "--no-server" ] || [ "$1" = "--no-daemon" ] || [ "$1" = "--help" ] ; then
+  # Need to preserve the first position of those listed options
+  MILL_FIRST_ARG=$1
+  shift
+fi
+
+unset MILL_FINAL_DOWNLOAD_FOLDER
+unset MILL_OLD_DOWNLOAD_PATH
+unset OLD_MILL
+unset MILL_VERSION
+unset MILL_REPO_URL
+
+# -D mill.main.cli is for compatibility with Mill 0.10.9 - 0.13.0-M2
+# We don't quote MILL_FIRST_ARG on purpose, so we can expand the empty value without quotes
+# shellcheck disable=SC2086
+exec "${MILL}" $MILL_FIRST_ARG -D "mill.main.cli=${MILL_MAIN_CLI}" "$@"
diff --git a/modules/cli/src/main/scala/cli.scala b/modules/cli/src/main/scala/main.scala
similarity index 97%
rename from modules/cli/src/main/scala/cli.scala
rename to modules/cli/src/main/scala/main.scala
index dd20351..c81be95 100644
--- a/modules/cli/src/main/scala/cli.scala
+++ b/modules/cli/src/main/scala/main.scala
@@ -1,7 +1,7 @@
 // for test runs using scala-cli
 //> using jvm system
-//> using scala 3.8.2
-//> using file ../../../../core/shared/src/main/scala/codegen.scala
+//> using scala 3.8.3
+//> using file ../../../../core/src/main/scala/codegen.scala
 //> using dep com.lihaoyi::upickle:4.4.3
 
 package gcp.codegen.cli
diff --git a/modules/core/shared/src/main/scala/codegen.scala b/modules/core/src/main/scala/codegen.scala
similarity index 100%
rename from modules/core/shared/src/main/scala/codegen.scala
rename to modules/core/src/main/scala/codegen.scala
diff --git a/modules/example-jsoniter-json/shared/src/main/scala/json.scala b/modules/example-jsoniter-json/src/main/scala/json.scala
similarity index 100%
rename from modules/example-jsoniter-json/shared/src/main/scala/json.scala
rename to modules/example-jsoniter-json/src/main/scala/json.scala
diff --git a/project/build.properties b/project/build.properties
deleted file mode 100644
index dabdb15..0000000
--- a/project/build.properties
+++ /dev/null
@@ -1 +0,0 @@
-sbt.version=1.12.11
diff --git a/build.sbt b/sbt_backup/build_sbt.bak
similarity index 86%
rename from build.sbt
rename to sbt_backup/build_sbt.bak
index 3427c82..5705c47 100644
--- a/build.sbt
+++ b/sbt_backup/build_sbt.bak
@@ -40,34 +40,30 @@ lazy val noPublish = Seq(
   publish / skip := true
 )
 
-val sttpClient4Version = "4.0.13"
+val sttpClient4Version = "4.0.23"
 
-val zioVersion = "2.1.23"
+val zioVersion = "2.1.26"
 
-val zioJsonVersion = "0.8.0"
+val zioJsonVersion = "0.9.1"
 
 val jsoniterVersion = "2.38.12"
 
-val munitVersion = "1.2.1"
+val munitVersion = "1.3.0"
 
 val upickleVersion = "4.4.3"
 
-addCommandAlias("fmt", "all scalafmtSbt scalafmt test:scalafmt")
+addCommandAlias("fmt", "all scalafmtSbt scalafmt Test/scalafmt")
 
 lazy val root = (project in file("."))
   .aggregate(
-    core.native,
-    core.jvm,
-    exampleJsoniterJson.native,
-    exampleJsoniterJson.jvm,
-    cli
+    (core.projectRefs ++ exampleJsoniterJson.projectRefs ++ Seq(LocalProject("cli")) ++ testProjects.componentProjects
+      .map(p => LocalProject(p.id))) *
   )
-  .aggregate(testProjects.componentProjects.map(p => LocalProject(p.id)) *)
   .settings(noPublish)
 
 // for supporting code inspection / testing of generated code via test_gen.sh script
 lazy val testLocal = (project in file("test-local"))
-  .dependsOn(exampleJsoniterJson.jvm)
+  .dependsOn(LocalProject("exampleJsoniterJson"))
   .settings(
     libraryDependencies ++= Seq(
       "com.softwaremill.sttp.client4" %% "core" % sttpClient4Version,
@@ -79,8 +75,7 @@ lazy val testLocal = (project in file("test-local"))
   )
   .settings(noPublish)
 
-lazy val core = crossProject(JVMPlatform, NativePlatform)
-  .in(file("modules/core"))
+lazy val core = (projectMatrix in file("modules/core"))
   .settings(publishSettings)
   .settings(
     name := "gcp-codegen",
@@ -88,24 +83,25 @@ lazy val core = crossProject(JVMPlatform, NativePlatform)
   )
   .settings(
     libraryDependencies ++= Seq(
-      "com.lihaoyi" %%% "upickle" % upickleVersion
+      "com.lihaoyi" %% "upickle" % upickleVersion
     )
   )
+  .jvmPlatform(scalaVersions = Seq("3.8.3"))
+  .nativePlatform(scalaVersions = Seq("3.8.3"))
 
 lazy val cli = project
   .in(file("modules/cli"))
-  .aggregate(core.native)
-  .dependsOn(core.native)
+  .aggregate(LocalProject("coreNative"))
+  .dependsOn(LocalProject("coreNative"))
   .enablePlugins(ScalaNativePlugin)
   .settings(publishSettings)
   .settings(
     name := "gcp-codegen-cli",
     moduleName := "gcp-codegen-cli",
-    nativeConfig := nativeConfig.value.withMultithreading(false)
+    nativeConfig ~= { _.withMultithreading(false) }
   )
 
-lazy val exampleJsoniterJson = crossProject(JVMPlatform, NativePlatform)
-  .in(file("modules/example-jsoniter-json"))
+lazy val exampleJsoniterJson = (projectMatrix in file("modules/example-jsoniter-json"))
   .settings(noPublish)
   .settings(
     name := "example-jsoniter-json",
@@ -117,6 +113,8 @@ lazy val exampleJsoniterJson = crossProject(JVMPlatform, NativePlatform)
       "com.github.plokhotnyuk.jsoniter-scala" %% "jsoniter-scala-macros" % jsoniterVersion % "compile-internal"
     )
   )
+  .jvmPlatform(scalaVersions = Seq("3.8.3"))
+  .nativePlatform(scalaVersions = Seq("3.8.3"))
 
 def dependencyByConfig(httpSource: String, jsonCodec: String, arrayType: String): Seq[ModuleID] = {
   (httpSource match {
@@ -182,7 +180,7 @@ lazy val testProjects: CompositeProject = new CompositeProject {
 }
 
 lazy val cliBinFile: File = {
-  val cliTarget = new File("modules/cli/target/bin")
+  val cliTarget = new File("target/bin")
 
   def normalise(s: String) = s.toLowerCase.replaceAll("[^a-z0-9]+", "")
   val props = sys.props.toMap
@@ -208,8 +206,8 @@ lazy val cliBinFile: File = {
 }
 
 lazy val buildCliBinary = taskKey[File]("")
-buildCliBinary := {
-  val built = (cli / Compile / nativeLinkReleaseFast).value
+buildCliBinary := Def.uncached {
+  val built = java.io.File((cli / Compile / nativeLinkReleaseFast).value.toString.replace(s"$${OUT}", "target/out"))
   IO.copyFile(built, cliBinFile)
   cliBinFile
 }
@@ -231,11 +229,11 @@ def codegenTask(
     val outSrcDir = outDir / "scala"
 
     @scala.annotation.tailrec
-    def listFilesRec(dir: List[File], res: List[File]): List[File] =
+    def listFilesRec(dir: List[File], res: Seq[File]): Seq[File] =
       dir match {
         case x :: xs =>
           val (dirs, files) = IO.listFiles(x).toList.partition(_.isDirectory())
-          listFilesRec(dirs ::: xs, files ::: res)
+          listFilesRec(dirs ::: xs, files ++ res)
         case Nil => res
       }
 
@@ -267,6 +265,6 @@ def codegenTask(
 
     val files = listFilesRec(List(outDir), Nil)
     IO.delete(outDir / ".scala-build")
-    files
+    files.toSeq
   }
 }
diff --git a/sbt_backup/project/build_properties.bak b/sbt_backup/project/build_properties.bak
new file mode 100644
index 0000000..ab6f7c0
--- /dev/null
+++ b/sbt_backup/project/build_properties.bak
@@ -0,0 +1 @@
+sbt.version=2.0.0-RC12
diff --git a/project/plugins.sbt b/sbt_backup/project/plugins_sbt.bak
similarity index 74%
rename from project/plugins.sbt
rename to sbt_backup/project/plugins_sbt.bak
index 0895661..eb56196 100644
--- a/project/plugins.sbt
+++ b/sbt_backup/project/plugins_sbt.bak
@@ -2,8 +2,6 @@ addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.5.12")
 
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.6")
 
-addSbtPlugin("org.portable-scala" % "sbt-scala-native-crossproject" % "1.3.2")
-
 addSbtPlugin("com.github.sbt" % "sbt-dynver" % "5.1.1")
 
 addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")