diff --git a/.circleci/config.yml b/.circleci/config.yml
index dfa66dadf7..a498260b45 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -15,6 +15,84 @@ executors:
       working_directory: /chronon
       docker:
         - image: houpy0829/chronon-ci:base--f87f50dc520f7a73894ae024eb78bd305d5b08e2
+    modern_ubuntu_executor:
+        resource_class: xlarge
+        working_directory: /chronon
+        docker:
+            - image: cimg/openjdk:11.0
+    modern_ubuntu_executor_xxlarge:
+        resource_class: 2xlarge
+        working_directory: /chronon
+        docker:
+            - image: cimg/openjdk:11.0
+
+commands:
+    install_build_dependencies:
+        description: "Install Thrift, Conda, SBT, and Mill on Ubuntu 22.04"
+        steps:
+            - run:
+                name: Install system dependencies
+                command: |
+                    sudo apt-get update
+                    sudo apt-get install -y \
+                        automake \
+                        bison \
+                        cmake \
+                        flex \
+                        g++ \
+                        git \
+                        libboost-dev \
+                        libboost-filesystem-dev \
+                        libboost-program-options-dev \
+                        libboost-system-dev \
+                        libboost-test-dev \
+                        libevent-dev \
+                        libssl-dev \
+                        libtool \
+                        make \
+                        pkg-config
+            - run:
+                name: Install Thrift 0.11.0 from source
+                command: |
+                    export THRIFT_VERSION=0.11.0
+                    curl -sSL "http://archive.apache.org/dist/thrift/$THRIFT_VERSION/thrift-$THRIFT_VERSION.tar.gz" -o thrift.tar.gz
+                    mkdir -p /tmp/thrift
+                    tar zxf thrift.tar.gz -C /tmp/thrift --strip-components=1
+                    rm thrift.tar.gz
+                    cd /tmp/thrift
+                    ./configure --without-python --without-cpp
+                    make
+                    sudo make install
+                    cd /
+                    rm -rf /tmp/thrift
+                    thrift --version
+            - run:
+                name: Install SBT
+                command: |
+                    echo "deb https://repo.scala-sbt.org/scalasbt/debian all main" | sudo tee /etc/apt/sources.list.d/sbt.list
+                    curl -sL "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x2EE0EA64E40A89B84B2DF73499E82A75642AC823" | sudo apt-key add
+                    sudo apt-get update
+                    sudo apt-get install -y sbt
+            - run:
+                name: Install Miniconda
+                command: |
+                    wget -q https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O ~/miniconda.sh
+                    bash ~/miniconda.sh -b -p $HOME/miniconda
+                    echo 'export PATH=$HOME/miniconda/bin:$PATH' >> $BASH_ENV
+                    source $BASH_ENV
+                    conda create -y -n chronon_py python=3.7
+                    conda install -y -q -n chronon_py --no-deps virtualenv
+                    $HOME/miniconda/envs/chronon_py/bin/pip install \
+                        flake8==5.0.4 flake8-quotes==3.3.1 thrift==0.11.0 click==7.0 thrift_json==0.1.0 nose>=1.3.7
+                    $HOME/miniconda/envs/chronon_py/bin/pip install build
+            - run:
+                name: Install Mill with checksum verification
+                command: |
+                    curl -L https://github.com/com-lihaoyi/mill/releases/download/0.10.15/0.10.15 -o mill
+                    echo "d90132b1a4ebe4d55d2bc43b3f18b5d6e8e3d12d89a83f83ad2276867e127916  mill" | sha256sum -c -
+                    chmod +x mill
+                    sudo mv mill /usr/local/bin/mill
+                    mill --version
 
 jobs:
     "Pull Docker Image":
@@ -195,6 +273,64 @@ jobs:
             destination: spark_warehouse.tar.gz
             when: on_fail
 
+    "Mill -- Compile All":
+      executor: modern_ubuntu_executor
+      steps:
+        - checkout
+        - install_build_dependencies
+        - run:
+            name: Compile all modules with Mill
+            shell: /bin/bash -leuxo pipefail
+            command: |
+              source $BASH_ENV
+              conda activate chronon_py
+              # Prepare scala version-specific sources for Mill
+              mill api.prepareScalaSources
+              # Compile all modules
+              mill api.compile aggregator.compile online.compile spark.compile flink.compile
+
+    "Mill -- Tests":
+      executor: modern_ubuntu_executor_xxlarge
+      steps:
+        - checkout
+        - install_build_dependencies
+        - run:
+            name: Run all tests with Mill
+            shell: /bin/bash -leuxo pipefail
+            command: |
+              source $BASH_ENV
+              conda activate chronon_py
+              mill api.prepareScalaSources
+              mill api.test aggregator.test online.test spark.test flink.test
+        - run:
+            name: Compress spark-warehouse
+            command: |
+              cd /tmp/ && tar -czvf spark-warehouse.tar.gz chronon/spark-warehouse
+            when: on_fail
+        - store_artifacts:
+            path: /tmp/spark-warehouse.tar.gz
+            destination: spark_warehouse.tar.gz
+            when: on_fail
+
+    "Mill -- Python API Build":
+      executor: modern_ubuntu_executor
+      steps:
+        - checkout
+        - install_build_dependencies
+        - run:
+            name: Build Python API with Mill
+            shell: /bin/bash -leuxo pipefail
+            command: |
+              source $BASH_ENV
+              conda activate chronon_py
+              # Set project root for Mill commands
+              export CHRONON_ROOT=/chronon
+              # Generate Python Thrift and build wheel
+              mill generatePythonThrift
+              mill buildPythonApi
+        - store_artifacts:
+            path: /chronon/api/py/dist
+
 workflows:
     build_test_deploy:
         jobs:
@@ -221,5 +357,14 @@ workflows:
                   requires:
                       - "Pull Docker Image"
             - "Scala 13 -- Iceberg Table Utils Tests":
+                  requires:
+                      - "Pull Docker Image"
+            - "Mill -- Compile All":
+                  requires:
+                      - "Pull Docker Image"
+            - "Mill -- Tests":
+                  requires:
+                      - "Pull Docker Image"
+            - "Mill -- Python API Build":
                   requires:
                       - "Pull Docker Image"
\ No newline at end of file
diff --git a/aggregator/package.mill b/aggregator/package.mill
new file mode 100644
index 0000000000..e312494507
--- /dev/null
+++ b/aggregator/package.mill
@@ -0,0 +1,69 @@
+package build.aggregator
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+object `package` extends SbtModule with PublishModule {
+
+  def scalaVersion = "2.12.12"
+
+  def mvnDeps = Seq(
+    mvn"com.google.code.gson:gson:2.8.6",
+    mvn"com.yahoo.datasketches:sketches-core:0.13.4",
+    mvn"org.apache.commons:commons-lang3:3.12.0"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.api)
+
+  def compileMvnDeps = Seq(
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1"
+  )
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "awhittier-mill-0.0.110-SNAPSHOT"
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"junit:junit:4.13.2",
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"org.scalatest::scalatest:3.2.15",
+      mvn"org.apache.commons:commons-math3:3.6.1"
+    )
+
+    def moduleDeps = super.moduleDeps ++ Seq(build.api.test)
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+  }
+}
diff --git a/api/package.mill b/api/package.mill
new file mode 100644
index 0000000000..b0f6e5658c
--- /dev/null
+++ b/api/package.mill
@@ -0,0 +1,105 @@
+package build.api
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+object `package` extends SbtModule with PublishModule {
+
+  def scalaVersion = "2.12.12"
+
+  def mvnDeps = Seq(
+    mvn"org.apache.thrift:libthrift:0.13.0",
+    mvn"org.scala-lang.modules::scala-collection-compat:2.6.0",
+    mvn"org.scala-lang:scala-reflect:2.12.12"
+  )
+
+  def compileMvnDeps = Seq(
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1"
+  )
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "awhittier-mill-0.0.110-SNAPSHOT"
+
+  /**
+   * Prepare Scala version-specific sources for Mill compilation.
+   *
+   * Mill's security model prevents reading from scala-2.12/ during Task execution,
+   * so we copy version-specific sources to the main scala/ directory before compilation.
+   *
+   * This is a one-time setup command - run it once per clean build:
+   *   ./mill api.prepareScalaSources
+   *
+   * SBT users don't need this - sbt automatically picks up scala-2.12/ directories.
+   */
+  def prepareScalaSources() = Task.Command {
+    val scala212Dir = millSourcePath0 / "src" / "main" / "scala-2.12"
+    val scalaDir = millSourcePath0 / "src" / "main" / "scala"
+
+    os.walk(scala212Dir)
+      .filter(_.ext == "scala")
+      .foreach { sourceFile =>
+        val relativePath = sourceFile.relativeTo(scala212Dir)
+        val targetFile = scalaDir / relativePath
+        os.makeDir.all(targetFile / os.up)
+        os.copy.over(sourceFile, targetFile, createFolders = true)
+        println(s"✓ Copied: ${sourceFile.last}")
+      }
+    println(s"✓ Scala 2.12 sources prepared for Mill compilation")
+    ()
+  }
+
+  // Generate Java sources from Thrift
+  def generatedSources = Task {
+    val thriftFile = millSourcePath0 / "thrift" / "api.thrift"
+    val outDir = Task.dest / "java"
+    os.remove.all(outDir)
+    os.makeDir.all(outDir)
+    os.proc("thrift", "--gen", "java", "-out", outDir, thriftFile)
+      .call(stdout = os.Inherit)
+
+    os.walk(outDir).filter(_.ext == "java").map(PathRef(_))
+  }
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"junit:junit:4.13.2",
+      mvn"org.scalatest::scalatest:3.2.15",
+      mvn"org.scalatestplus::mockito-3-4:3.2.10.0"
+    )
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+  }
+}
diff --git a/api/py/python-api-build.sh b/api/py/python-api-build.sh
index a984be5ee0..144b17f28c 100755
--- a/api/py/python-api-build.sh
+++ b/api/py/python-api-build.sh
@@ -26,6 +26,23 @@ SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
 echo "Removing old distributions..."
 rm -f $SCRIPT_DIR/dist/*
 
+# Create and activate venv if it doesn't exist
+VENV_DIR="$SCRIPT_DIR/../../venv"
+if [[ ! -d "$VENV_DIR" ]]; then
+  echo "Creating Python virtual environment..."
+  python3 -m venv "$VENV_DIR"
+fi
+
+# Activate venv
+echo "Activating Python virtual environment..."
+source "$VENV_DIR/bin/activate"
+
+# Install build dependencies in venv if needed
+if ! python3 -c "import build" 2>/dev/null; then
+  echo "Installing Python build dependencies..."
+  pip install --quiet build twine
+fi
+
 # The default action is "build"
 if [[ -z "${ACTION}" ]] || [[ "${ACTION}" == "build" ]]; then
   PYPI_REPOSITORY="internal"
diff --git a/build.mill b/build.mill
new file mode 100644
index 0000000000..81179bdff7
--- /dev/null
+++ b/build.mill
@@ -0,0 +1,116 @@
+//| mill-version: 1.0.6
+package build
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+// Compute project root - use environment variable override for CI, otherwise detect from git
+val PROJECT_ROOT = os.Path(sys.env.getOrElse("CHRONON_ROOT",
+  os.proc("git", "rev-parse", "--show-toplevel").call().out.text().trim()
+))
+
+object `package` extends SbtModule with PublishModule {
+
+  def artifactName = "chronon"
+
+  def scalaVersion = "2.12.12"
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "0.0.110-SNAPSHOT"
+
+  /**
+   * Generate Python Thrift sources from api.thrift
+   * Usage: ./mill generatePythonThrift
+   */
+  def generatePythonThrift() = Task.Command {
+    // Use captured project root directory
+    val root = PROJECT_ROOT
+    val thriftFile = root / "api" / "thrift" / "api.thrift"
+    val outDir = root / "api" / "py" / "ai" / "chronon"
+
+    println(s"Generating Python Thrift files from: $thriftFile")
+    println(s"Output directory: $outDir")
+
+    // Remove old generated files
+    if (os.exists(outDir / "api")) {
+      os.remove.all(outDir / "api")
+    }
+
+    // Generate Python Thrift files
+    os.proc("thrift", "--gen", "py", "-out", outDir, thriftFile)
+      .call(cwd = root, stdout = os.Inherit, stderr = os.Inherit)
+
+    println("Python Thrift generation completed!")
+    ()
+  }
+
+  /**
+   * Build Python API wheel
+   * Usage: ./mill buildPythonApi
+   * Usage: ./mill buildPythonApi --action release
+   */
+  def buildPythonApi(action: String = "build") = Task.Command {
+    println(s"Building Python API with action: $action")
+
+    // Generate Python Thrift first
+    generatePythonThrift()()
+
+    // Use captured project root directory
+    val root = PROJECT_ROOT
+
+    // Get version and branch for Python API (mirroring sbt's git.versionProperty)
+    val branchStr = os.proc("git", "rev-parse", "--abbrev-ref", "HEAD")
+      .call(cwd = root)
+      .out
+      .text()
+      .trim()
+      .replace("/", "-")
+
+    // Read version from version.sbt
+    val baseVersion = "0.0.110-SNAPSHOT"
+    val versionStr = if (branchStr == "main" || branchStr == "master") {
+      baseVersion
+    } else {
+      s"${branchStr}-${baseVersion}"
+    }
+
+    println(s"Version: $versionStr, Branch: $branchStr")
+
+    // Run the Python API build script
+    val script = root / "api" / "py" / "python-api-build.sh"
+    os.proc(script, versionStr, branchStr, action)
+      .call(cwd = root, stdout = os.Inherit, stderr = os.Inherit)
+
+    println(s"Python API $action completed!")
+    ()
+  }
+
+}
diff --git a/flink/package.mill b/flink/package.mill
new file mode 100644
index 0000000000..34629ae45f
--- /dev/null
+++ b/flink/package.mill
@@ -0,0 +1,73 @@
+package build.flink
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+object `package` extends SbtModule with PublishModule {
+
+  def scalaVersion = "2.12.12"
+
+  def mvnDeps = Seq(
+    mvn"org.apache.avro:avro:1.8.2",
+    mvn"org.apache.flink::flink-streaming-scala:1.16.1",
+    mvn"org.apache.flink:flink-clients:1.16.1",
+    mvn"org.apache.flink:flink-metrics-dropwizard:1.16.1",
+    mvn"org.apache.flink:flink-test-utils:1.16.1"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.aggregator, build.online)
+
+  def compileMvnDeps = Seq(
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-hive:3.1.1",
+    mvn"org.apache.spark::spark-sql-kafka-0-10:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1",
+    mvn"org.apache.spark::spark-streaming:3.1.1"
+  )
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "cb0ceedc95c0a4602315424f558e418f4c2628ef-SNAPSHOT"
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"junit:junit:4.13.2",
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"org.scalatest::scalatest:3.2.15"
+    )
+
+    def moduleDeps = super.moduleDeps ++ Seq(build.aggregator.test)
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+  }
+}
diff --git a/mill b/mill
new file mode 100755
index 0000000000..136be4dfe1
--- /dev/null
+++ b/mill
@@ -0,0 +1,339 @@
+#!/usr/bin/env sh
+
+# This is a wrapper script, that automatically selects or downloads Mill from Maven Central or GitHub release pages.
+#
+# This script determines the Mill version to use by trying these sources
+#   - env-variable `MILL_VERSION`
+#   - local file `.mill-version`
+#   - local file `.config/mill-version`
+#   - `mill-version` from YAML frontmatter of current buildfile
+#   - if accessible, find the latest stable version available on Maven Central (https://repo1.maven.org/maven2)
+#   - env-variable `DEFAULT_MILL_VERSION`
+#
+# If a version has the suffix '-native' a native binary will be used.
+# If a version has the suffix '-jvm' an executable jar file will be used, requiring an already installed Java runtime.
+# If no such suffix is found, the script will pick a default based on version and platform.
+#
+# Once a version was determined, it tries to use either
+#    - a system-installed mill, if found and it's version matches
+#    - an already downloaded version under ~/.cache/mill/download
+#
+# If no working mill version was found on the system,
+# this script downloads a binary file from Maven Central or Github Pages (this is version dependent)
+# into a cache location (~/.cache/mill/download).
+#
+# Mill Project URL: https://github.com/com-lihaoyi/mill
+# Script Version: 1.0.6
+#
+# If you want to improve this script, please also contribute your changes back!
+# This script was generated from: dist/scripts/src/mill.sh
+#
+# Licensed under the Apache License, Version 2.0
+
+set -e
+
+if [ -z "${DEFAULT_MILL_VERSION}" ] ; then
+  DEFAULT_MILL_VERSION="1.0.6"
+fi
+
+
+if [ -z "${GITHUB_RELEASE_CDN}" ] ; then
+  GITHUB_RELEASE_CDN=""
+fi
+
+
+MILL_REPO_URL="https://github.com/com-lihaoyi/mill"
+
+if [ -z "${CURL_CMD}" ] ; then
+  CURL_CMD=curl
+fi
+
+# Explicit commandline argument takes precedence over all other methods
+if [ "$1" = "--mill-version" ] ; then
+    echo "The --mill-version option is no longer supported." 1>&2
+fi
+
+MILL_BUILD_SCRIPT=""
+
+if [ -f "build.mill" ] ; then
+  MILL_BUILD_SCRIPT="build.mill"
+elif [ -f "build.mill.scala" ] ; then
+  MILL_BUILD_SCRIPT="build.mill.scala"
+elif [ -f "build.sc" ] ; then
+  MILL_BUILD_SCRIPT="build.sc"
+fi
+
+# Please note, that if a MILL_VERSION is already set in the environment,
+# We reuse it's value and skip searching for a value.
+
+# If not already set, read .mill-version file
+if [ -z "${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 [ -n "${MILL_BUILD_SCRIPT}" ] ; then
+    # `s/.*://`:
+    #   This is a greedy match that removes everything from the beginning of the line up to (and including) the last
+    #   colon (:). This effectively isolates the value part of the declaration.
+    #
+    #  `s/#.*//`:
+    #    This removes any comments at the end of the line.
+    #
+    #  `s/['\"]//g`:
+    #    This removes all single and double quotes from the string, wherever they appear (g is for "global").
+    #
+    #  `s/^[[:space:]]*//; s/[[:space:]]*$//`:
+    #    These two expressions trim any leading or trailing whitespace ([[:space:]] matches spaces and tabs).
+    MILL_VERSION="$(grep -E "//\|.*mill-version" "${MILL_BUILD_SCRIPT}" | sed -E "s/.*://; s/#.*//; s/['\"]//g; s/^[[:space:]]*//; s/[[:space:]]*$//")"
+  fi
+fi
+
+MILL_USER_CACHE_DIR="${XDG_CACHE_HOME:-${HOME}/.cache}/mill"
+
+if [ -z "${MILL_DOWNLOAD_PATH}" ] ; then
+  MILL_DOWNLOAD_PATH="${MILL_USER_CACHE_DIR}/download"
+fi
+
+# If not already set, try to fetch newest from Github
+if [ -z "${MILL_VERSION}" ] ; then
+  # TODO: try to load latest version from release page
+  echo "No mill version specified." 1>&2
+  echo "You should provide a version via a '//| mill-version: ' comment or a '.mill-version' file." 1>&2
+
+  mkdir -p "${MILL_DOWNLOAD_PATH}"
+  LANG=C touch -d '1 hour ago' "${MILL_DOWNLOAD_PATH}/.expire_latest" 2>/dev/null || (
+    # we might be on OSX or BSD which don't have -d option for touch
+    # but probably a -A [-][[hh]mm]SS
+    touch "${MILL_DOWNLOAD_PATH}/.expire_latest"; touch -A -010000 "${MILL_DOWNLOAD_PATH}/.expire_latest"
+  ) || (
+    # in case we still failed, we retry the first touch command with the intention
+    # to show the (previously suppressed) error message
+    LANG=C touch -d '1 hour ago' "${MILL_DOWNLOAD_PATH}/.expire_latest"
+  )
+
+  # POSIX shell variant of bash's -nt operator, see https://unix.stackexchange.com/a/449744/6993
+  # if [ "${MILL_DOWNLOAD_PATH}/.latest" -nt "${MILL_DOWNLOAD_PATH}/.expire_latest" ] ; then
+  if [ -n "$(find -L "${MILL_DOWNLOAD_PATH}/.latest" -prune -newer "${MILL_DOWNLOAD_PATH}/.expire_latest")" ]; then
+    # we know a current latest version
+    MILL_VERSION=$(head -n 1 "${MILL_DOWNLOAD_PATH}"/.latest 2> /dev/null)
+  fi
+
+  if [ -z "${MILL_VERSION}" ] ; then
+    # we don't know a current latest version
+    echo "Retrieving latest mill version ..." 1>&2
+    LANG=C ${CURL_CMD} -s -i -f -I ${MILL_REPO_URL}/releases/latest 2> /dev/null  | grep --ignore-case Location: | sed s'/^.*tag\///' | tr -d '\r\n' > "${MILL_DOWNLOAD_PATH}/.latest"
+    MILL_VERSION=$(head -n 1 "${MILL_DOWNLOAD_PATH}"/.latest 2> /dev/null)
+  fi
+
+  if [ -z "${MILL_VERSION}" ] ; then
+    # Last resort
+    MILL_VERSION="${DEFAULT_MILL_VERSION}"
+    echo "Falling back to hardcoded mill version ${MILL_VERSION}" 1>&2
+  else
+    echo "Using mill version ${MILL_VERSION}" 1>&2
+  fi
+fi
+
+MILL_NATIVE_SUFFIX="-native"
+MILL_JVM_SUFFIX="-jvm"
+FULL_MILL_VERSION=$MILL_VERSION
+ARTIFACT_SUFFIX=""
+set_artifact_suffix(){
+  if [ "$(expr substr $(uname -s) 1 5 2>/dev/null)" = "Linux" ]; then
+    if [ "$(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="${MILL_DOWNLOAD_PATH}/$MILL_VERSION$ARTIFACT_SUFFIX"
+
+try_to_use_system_mill() {
+  if [ "$(uname)" != "Linux" ]; then
+    return 0
+  fi
+
+  MILL_IN_PATH="$(command -v mill || true)"
+
+  if [ -z "${MILL_IN_PATH}" ]; then
+    return 0
+  fi
+
+  SYSTEM_MILL_FIRST_TWO_BYTES=$(head --bytes=2 "${MILL_IN_PATH}")
+  if [ "${SYSTEM_MILL_FIRST_TWO_BYTES}" = "#!" ]; then
+	  # MILL_IN_PATH is (very likely) a shell script and not the mill
+	  # executable, ignore it.
+	  return 0
+  fi
+
+  SYSTEM_MILL_PATH=$(readlink -e "${MILL_IN_PATH}")
+  SYSTEM_MILL_SIZE=$(stat --format=%s "${SYSTEM_MILL_PATH}")
+  SYSTEM_MILL_MTIME=$(stat --format=%y "${SYSTEM_MILL_PATH}")
+
+  if [ ! -d "${MILL_USER_CACHE_DIR}" ]; then
+    mkdir -p "${MILL_USER_CACHE_DIR}"
+  fi
+
+  SYSTEM_MILL_INFO_FILE="${MILL_USER_CACHE_DIR}/system-mill-info"
+  if [ -f "${SYSTEM_MILL_INFO_FILE}" ]; then
+    parseSystemMillInfo() {
+        LINE_NUMBER="${1}"
+        # Select the line number of the SYSTEM_MILL_INFO_FILE, cut the
+        # variable definition in that line in two halves and return
+        # the value, and finally remove the quotes.
+        sed -n "${LINE_NUMBER}p" "${SYSTEM_MILL_INFO_FILE}" |\
+            cut -d= -f2 |\
+            sed 's/"\(.*\)"/\1/'
+    }
+
+    CACHED_SYSTEM_MILL_PATH=$(parseSystemMillInfo 1)
+    CACHED_SYSTEM_MILL_VERSION=$(parseSystemMillInfo 2)
+    CACHED_SYSTEM_MILL_SIZE=$(parseSystemMillInfo 3)
+    CACHED_SYSTEM_MILL_MTIME=$(parseSystemMillInfo 4)
+
+    if [ "${SYSTEM_MILL_PATH}" = "${CACHED_SYSTEM_MILL_PATH}" ] \
+           && [ "${SYSTEM_MILL_SIZE}" = "${CACHED_SYSTEM_MILL_SIZE}" ] \
+           && [ "${SYSTEM_MILL_MTIME}" = "${CACHED_SYSTEM_MILL_MTIME}" ]; then
+      if [ "${CACHED_SYSTEM_MILL_VERSION}" = "${MILL_VERSION}" ]; then
+          MILL="${SYSTEM_MILL_PATH}"
+          return 0
+      else
+          return 0
+      fi
+    fi
+  fi
+
+  SYSTEM_MILL_VERSION=$(${SYSTEM_MILL_PATH} --version | head -n1 | sed -n 's/^Mill.*version \(.*\)/\1/p')
+
+  cat <<EOF > "${SYSTEM_MILL_INFO_FILE}"
+CACHED_SYSTEM_MILL_PATH="${SYSTEM_MILL_PATH}"
+CACHED_SYSTEM_MILL_VERSION="${SYSTEM_MILL_VERSION}"
+CACHED_SYSTEM_MILL_SIZE="${SYSTEM_MILL_SIZE}"
+CACHED_SYSTEM_MILL_MTIME="${SYSTEM_MILL_MTIME}"
+EOF
+
+  if [ "${SYSTEM_MILL_VERSION}" = "${MILL_VERSION}" ]; then
+    MILL="${SYSTEM_MILL_PATH}"
+  fi
+}
+try_to_use_system_mill
+
+# 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.* )
+      DOWNLOAD_SUFFIX=""
+      DOWNLOAD_FROM_MAVEN=0
+      ;;
+    0.5.* | 0.6.* | 0.7.* | 0.8.* | 0.9.* | 0.10.* | 0.11.0-M* )
+      DOWNLOAD_SUFFIX="-assembly"
+      DOWNLOAD_FROM_MAVEN=0
+      ;;
+    *)
+      DOWNLOAD_SUFFIX="-assembly"
+      DOWNLOAD_FROM_MAVEN=1
+      ;;
+  esac
+  case $MILL_VERSION in
+    0.12.0 | 0.12.1 | 0.12.2 | 0.12.3 | 0.12.4 | 0.12.5 | 0.12.6 | 0.12.7 | 0.12.8 | 0.12.9 | 0.12.10 | 0.12.11 )
+      DOWNLOAD_EXT="jar"
+      ;;
+    0.12.* )
+      DOWNLOAD_EXT="exe"
+      ;;
+    0.* )
+      DOWNLOAD_EXT="jar"
+      ;;
+    *)
+      DOWNLOAD_EXT="exe"
+      ;;
+  esac
+
+  DOWNLOAD_FILE=$(mktemp mill.XXXXXX)
+  if [ "$DOWNLOAD_FROM_MAVEN" = "1" ] ; then
+    DOWNLOAD_URL="https://repo1.maven.org/maven2/com/lihaoyi/mill-dist${ARTIFACT_SUFFIX}/${MILL_VERSION}/mill-dist${ARTIFACT_SUFFIX}-${MILL_VERSION}.${DOWNLOAD_EXT}"
+  else
+    MILL_VERSION_TAG=$(echo "$MILL_VERSION" | sed -E 's/([^-]+)(-M[0-9]+)?(-.*)?/\1\2/')
+    DOWNLOAD_URL="${GITHUB_RELEASE_CDN}${MILL_REPO_URL}/releases/download/${MILL_VERSION_TAG}/${MILL_VERSION}${DOWNLOAD_SUFFIX}"
+    unset MILL_VERSION_TAG
+  fi
+
+  if [ "$MILL_TEST_DRY_RUN_LAUNCHER_SCRIPT" = "1" ] ; then
+    echo $DOWNLOAD_URL
+    echo $MILL
+    exit 0
+  fi
+  # TODO: handle command not found
+  echo "Downloading mill ${MILL_VERSION} from ${DOWNLOAD_URL} ..." 1>&2
+  ${CURL_CMD} -f -L -o "${DOWNLOAD_FILE}" "${DOWNLOAD_URL}"
+  chmod +x "${DOWNLOAD_FILE}"
+  mkdir -p "${MILL_DOWNLOAD_PATH}"
+  mv "${DOWNLOAD_FILE}" "${MILL}"
+
+  unset DOWNLOAD_FILE
+  unset DOWNLOAD_SUFFIX
+fi
+
+if [ -z "$MILL_MAIN_CLI" ] ; then
+  MILL_MAIN_CLI="${0}"
+fi
+
+MILL_FIRST_ARG=""
+if [ "$1" = "--bsp" ] || [ "${1#"-i"}" != "$1" ] || [ "$1" = "--interactive" ] || [ "$1" = "--no-server" ] || [ "$1" = "--no-daemon" ] || [ "$1" = "--repl" ] || [ "$1" = "--help" ] ; then
+  # Need to preserve the first position of those listed options
+  MILL_FIRST_ARG=$1
+  shift
+fi
+
+unset MILL_DOWNLOAD_PATH
+unset MILL_OLD_DOWNLOAD_PATH
+unset OLD_MILL
+unset MILL_VERSION
+unset MILL_REPO_URL
+
+# -D mill.main.cli is for compatibility with Mill 0.10.9 - 0.13.0-M2
+# We don't quote MILL_FIRST_ARG on purpose, so we can expand the empty value without quotes
+# shellcheck disable=SC2086
+exec "${MILL}" $MILL_FIRST_ARG -D "mill.main.cli=${MILL_MAIN_CLI}" "$@"
diff --git a/online/package.mill b/online/package.mill
new file mode 100644
index 0000000000..e286776de4
--- /dev/null
+++ b/online/package.mill
@@ -0,0 +1,150 @@
+package build.online
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+// online: default shaded build with embedded dependencies
+object `package` extends SbtModule with PublishModule {
+
+  def scalaVersion = "2.12.12"
+
+  def mvnDeps = Seq(
+    mvn"com.datadoghq:java-dogstatsd-client:2.7",
+    mvn"com.github.ben-manes.caffeine:caffeine:2.8.5",
+    mvn"io.netty:netty-buffer:4.1.68.Final",
+    mvn"net.jodah:typetools:0.4.1",
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-hive:3.1.1",
+    mvn"org.apache.spark::spark-sql-kafka-0-10:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1",
+    mvn"org.apache.spark::spark-streaming:3.1.1",
+    mvn"org.rogach::scallop:4.0.1",
+    mvn"org.scala-lang.modules::scala-java8-compat:0.9.0"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.aggregator)
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "awhittier-mill-0.0.110-SNAPSHOT"
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"junit:junit:4.13.2",
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"org.scalatest::scalatest:3.2.15"
+    )
+
+    def moduleDeps = super.moduleDeps ++ Seq(build.aggregator.test)
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+  }
+
+  // online_unshaded: unshaded build with provided dependencies
+  object unshaded extends SbtModule with PublishModule {
+
+  def artifactName = "online_unshaded"
+
+  def scalaVersion = "2.12.12"
+
+  // Use same source directory as online (parent directory)
+  def millSourcePath: os.Path = os.pwd / "online"
+
+  def mvnDeps = Seq(
+    mvn"com.datadoghq:java-dogstatsd-client:2.7",
+    mvn"com.github.ben-manes.caffeine:caffeine:2.8.5",
+    mvn"io.netty:netty-buffer:4.1.68.Final",
+    mvn"net.jodah:typetools:0.4.1",
+    mvn"org.rogach::scallop:4.0.1",
+    mvn"org.scala-lang.modules::scala-java8-compat:0.9.0"
+  )
+
+  def compileMvnDeps = Seq(
+    mvn"com.fasterxml.jackson.core:jackson-core:2.10.0",
+    mvn"com.fasterxml.jackson.core:jackson-databind:2.10.0",
+    mvn"com.fasterxml.jackson.module::jackson-module-scala:2.10.0",
+    mvn"org.apache.avro:avro:1.8.2",
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-hive:3.1.1",
+    mvn"org.apache.spark::spark-sql-kafka-0-10:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1",
+    mvn"org.apache.spark::spark-streaming:3.1.1"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.aggregator)
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "awhittier-mill-0.0.110-SNAPSHOT"
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"junit:junit:4.13.2",
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"org.scalatest::scalatest:3.2.15"
+    )
+
+    def moduleDeps = super.moduleDeps ++ Seq(build.aggregator.test)
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+    }
+  }
+}
diff --git a/online/src/test/scala/ai/chronon/online/FetcherCacheTest.scala b/online/src/test/scala/ai/chronon/online/FetcherCacheTest.scala
index 8625cf56a3..e6297fdd32 100644
--- a/online/src/test/scala/ai/chronon/online/FetcherCacheTest.scala
+++ b/online/src/test/scala/ai/chronon/online/FetcherCacheTest.scala
@@ -328,7 +328,7 @@ class FetcherCacheTest extends MockitoHelper {
                                                                                servingInfo.outputCodec.decodeMap,
                                                                                servingInfo,
                                                                                keys)
-    verify(servingInfo.outputCodec.decodeMap(any()), times(1)) // decoding did happen
+    verify(outputCodec, times(1)).decodeMap(any()) // decoding did happen
     assertEquals(mapResponse, decodedMapResponse)
   }
 }
diff --git a/service/package.mill b/service/package.mill
new file mode 100644
index 0000000000..d55916ed90
--- /dev/null
+++ b/service/package.mill
@@ -0,0 +1,71 @@
+package build.service
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+object `package` extends SbtModule with PublishModule {
+
+  def scalaVersion = "2.12.12"
+
+  def mvnDeps = Seq(
+    mvn"ch.qos.logback:logback-classic:1.2.11",
+    mvn"com.typesafe:config:1.4.3",
+    mvn"io.micrometer:micrometer-registry-statsd:1.13.6",
+    mvn"io.netty:netty-all:4.1.111.Final",
+    mvn"io.vertx:vertx-config:4.5.10",
+    mvn"io.vertx:vertx-core:4.5.10",
+    mvn"io.vertx:vertx-micrometer-metrics:4.5.10",
+    mvn"io.vertx:vertx-web:4.5.10",
+    mvn"org.slf4j:slf4j-api:1.7.36"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.online)
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "cb0ceedc95c0a4602315424f558e418f4c2628ef-SNAPSHOT"
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"io.vertx:vertx-codegen:4.5.10",
+      mvn"io.vertx:vertx-unit:4.5.10",
+      mvn"junit:junit:4.13.2",
+      mvn"org.mockito:mockito-core:4.11.0"
+    )
+
+    def moduleDeps = super.moduleDeps ++ Seq(build.online.test)
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+  }
+}
diff --git a/spark/package.mill b/spark/package.mill
new file mode 100644
index 0000000000..8a39147414
--- /dev/null
+++ b/spark/package.mill
@@ -0,0 +1,144 @@
+package build.spark
+
+import mill._
+import mill.javalib._
+import mill.javalib.publish._
+import mill.scalalib.SbtModule
+
+// spark_uber: provided dependencies (for shaded/uber jar)
+object `package` extends SbtModule with PublishModule {
+
+  def artifactName = "spark_uber"
+
+  def scalaVersion = "2.12.12"
+
+  def mvnDeps = Seq(
+    mvn"com.fasterxml.jackson.core:jackson-core:2.10.0",
+    mvn"com.fasterxml.jackson.core:jackson-databind:2.10.0",
+    mvn"com.fasterxml.jackson.module::jackson-module-scala:2.10.0"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.aggregator, build.online)
+
+  def compileMvnDeps = Seq(
+    mvn"io.delta::delta-core:1.0.1",
+    mvn"org.apache.iceberg::iceberg-spark-runtime-3.2:1.1.0",
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-hive:3.1.1",
+    mvn"org.apache.spark::spark-sql-kafka-0-10:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1",
+    mvn"org.apache.spark::spark-streaming:3.1.1"
+  )
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "awhittier-mill-0.0.110-SNAPSHOT"
+
+  object test extends SbtTests with TestModule.Junit4 {
+
+    def mvnDeps = Seq(
+      mvn"junit:junit:4.13.2",
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"org.scalatest::scalatest:3.2.15",
+      mvn"org.xerial.snappy:snappy-java:1.1.8.4"
+    )
+
+    def moduleDeps = super.moduleDeps ++ Seq(build.aggregator.test)
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+
+  }
+
+  // spark_embedded: embedded dependencies (not provided)
+  object embedded extends SbtModule with PublishModule {
+
+  def artifactName = "spark_embedded"
+
+  def scalaVersion = "2.12.12"
+
+  // Use same source directory as spark_uber (parent directory)
+  def millSourcePath: os.Path = os.pwd / "spark"
+
+  def mvnDeps = Seq(
+    mvn"com.fasterxml.jackson.core:jackson-core:2.10.0",
+    mvn"com.fasterxml.jackson.core:jackson-databind:2.10.0",
+    mvn"com.fasterxml.jackson.module::jackson-module-scala:2.10.0",
+    mvn"io.delta::delta-core:1.0.1",
+    mvn"org.apache.iceberg::iceberg-spark-runtime-3.2:1.1.0",
+    mvn"org.apache.spark::spark-core:3.1.1",
+    mvn"org.apache.spark::spark-hive:3.1.1",
+    mvn"org.apache.spark::spark-sql-kafka-0-10:3.1.1",
+    mvn"org.apache.spark::spark-sql:3.1.1",
+    mvn"org.apache.spark::spark-streaming:3.1.1"
+  )
+
+  def moduleDeps = super.moduleDeps ++ Seq(build.aggregator, build.online)
+
+  def pomSettings = PomSettings(
+    "Chronon is a feature engineering platform",
+    "ai.chronon",
+    "https://github.com/airbnb/chronon",
+    Seq(License(
+      "Apache 2",
+      "Apache 2",
+      "http://www.apache.org/licenses/LICENSE-2.0.txt",
+      false,
+      false,
+      "repo"
+    )),
+    VersionControl(
+      Some("https://github.com/airbnb/chronon"),
+      Some("scm:git@github.com:airbnb/chronon.git"),
+      None,
+      None
+    ),
+    Seq(Developer(
+      "nikhilsimha",
+      "Nikhil Simha",
+      "http://nikhilsimha.com",
+      None,
+      None
+    ))
+  )
+
+  def publishVersion = "awhittier-mill-0.0.110-SNAPSHOT"
+
+  // Tests disabled for embedded variant (matching sbt build)
+  object test extends SbtTests with TestModule.Junit4 {
+    def mvnDeps = Seq(
+      mvn"junit:junit:4.13.2",
+      mvn"com.novocode:junit-interface:0.11",
+      mvn"org.scalatest::scalatest:3.2.15"
+    )
+
+    def testSandboxWorkingDir = false
+    def testParallelism = false
+    }
+  }
+}
diff --git a/spark/src/test/scala/ai/chronon/spark/test/MetadataExporterTest.scala b/spark/src/test/scala/ai/chronon/spark/test/MetadataExporterTest.scala
index 5019dcf4c3..46d39808f4 100644
--- a/spark/src/test/scala/ai/chronon/spark/test/MetadataExporterTest.scala
+++ b/spark/src/test/scala/ai/chronon/spark/test/MetadataExporterTest.scala
@@ -78,10 +78,13 @@ class MetadataExporterTest extends TestCase {
     val sampleDf = DataFrameGen
       .events(spark, sampleData, 10000, partitions = 30)
     sampleDf.save(sampleTable)
-    val confResource = getClass.getResource("/")
+
+    // Use the actual file system path to test resources instead of getResource
+    // which can return a JAR path in Mill
+    val testResourcesPath = new File("spark/src/test/resources").getAbsolutePath
     val tmpDir: File = Files.createTempDir()
-    MetadataExporter.run(confResource.getPath, Some(tmpDir.getAbsolutePath))
-    printFilesInDirectory(s"${confResource.getPath}/joins/team")
+    MetadataExporter.run(testResourcesPath, Some(tmpDir.getAbsolutePath))
+    printFilesInDirectory(s"$testResourcesPath/joins/team")
     printFilesInDirectory(s"${tmpDir.getAbsolutePath}/joins")
     // Read the files.
     val file = Source.fromFile(s"${tmpDir.getAbsolutePath}/joins/example_join.v1")