diff --git a/.github/workflows/pre-commit.yml b/.github/workflows/pre-commit.yml
index 39c1e65..c5838e5 100644
--- a/.github/workflows/pre-commit.yml
+++ b/.github/workflows/pre-commit.yml
@@ -1,9 +1,8 @@
 name: pre-commit
 
 on:
+  workflow_dispatch:
   pull_request:
-  push:
-    branches: [main]
 
 jobs:
   pre-commit:
diff --git a/.github/workflows/ubuntu-build.yml b/.github/workflows/ubuntu-build.yml
new file mode 100644
index 0000000..9285e72
--- /dev/null
+++ b/.github/workflows/ubuntu-build.yml
@@ -0,0 +1,45 @@
+name: ubuntu-build
+
+on:
+  workflow_dispatch:
+  pull_request:
+
+concurrency:
+  group: ci-${{github.workflow}}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    name: ubuntu-build
+    steps:
+      - name: Show env
+        run: env
+
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Install Build Dependencies
+        shell: bash
+        run: |
+          sudo apt update && sudo apt install --no-install-recommends -y \
+          cmake \
+          make
+
+      - name: Show Python version and platform info
+        run: |
+          python --version
+          python -m platform
+
+      - name: Show CMake version
+        run: cmake --version
+
+      - name: CMake Configure
+        shell: bash
+        run: |
+          cmake -S . -B build -DCMAKE_VERBOSE_MAKEFILE=ON
+
+      - name: CMake Build
+        shell: bash
+        run: |
+          cmake --build build -j$(nproc)
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..9424d86
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,166 @@
+cmake_minimum_required(VERSION 3.18)
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+project(pybind11_protobuf)
+
+if(MSVC)
+  set(CMAKE_CXX_STANDARD 20)
+else()
+  set(CMAKE_CXX_STANDARD 17)
+endif()
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+set(CMAKE_CXX_FLAGS
+    "-fPIC"
+    CACHE INTERNAL "")
+
+# ============================================================================
+# Options
+
+option(BUILD_absl "Build the abseil-cpp dependency Library" ON)
+message(STATUS "Build abseil-cpp: ${BUILD_absl}")
+
+option(BUILD_protobuf "Build the Protobuf dependency Library" ON)
+message(STATUS "Build protobuf: ${BUILD_protobuf}")
+
+option(BUILD_pybind11 "Build the pybind11 dependency Library" ON)
+message(STATUS "Python: Build pybind11: ${BUILD_pybind11}")
+
+# ============================================================================
+# Find Python
+
+find_package(Python COMPONENTS Interpreter Development)
+
+# ============================================================================
+# Build dependencies
+
+add_subdirectory(cmake/dependencies dependencies)
+
+include(deps)
+
+include(CMakeFindDependencyMacro)
+include(FindProtobuf)
+if(NOT protobuf_FOUND
+   AND NOT PROTOBUF_FOUND
+   AND NOT TARGET protobuf::libprotobuf)
+  if(BUILD_protobuf)
+    find_dependency(protobuf CONFIG REQUIRED)
+  endif()
+endif()
+
+# ============================================================================
+# Debug messages for find_package
+
+# message("pybind11_FOUND: ${pybind11_FOUND}") message("pybind11_VERSION:
+# ${pybind11_VERSION}") message("pybind11_VERSION_TYPE:
+# ${pybind11_VERSION_TYPE}") message("pybind11_INCLUDE_DIRS:
+# ${pybind11_INCLUDE_DIRS}") message("pybind11_INCLUDE_DIR:
+# ${pybind11_INCLUDE_DIR}") message("pybind11_DEFINITIONS:
+# ${pybind11_DEFINITIONS}") message("pybind11_LIBRARIES: ${pybind11_LIBRARIES}")
+
+# message("Python_FOUND: ${Python_FOUND}") message("Python_VERSION:
+# ${Python_VERSION}") message("Python_INCLUDE_DIRS: ${Python_INCLUDE_DIRS}")
+# message("Python_LIBRARIES: ${Python_LIBRARIES}")
+
+# message("protobuf_FOUND: ${protobuf_FOUND}") message("protobuf_VERSION:
+# ${protobuf_VERSION}") message("protobuf_INCLUDE_DIRS:
+# ${protobuf_INCLUDE_DIRS}") message("protobuf_SOURCE_DIR:
+# ${protobuf_SOURCE_DIR}") message("protobuf_LIBRARIES: ${protobuf_LIBRARIES}")
+
+# ============================================================================
+# pybind11_proto_utils pybind11 extension module
+pybind11_add_module(
+  pybind11_proto_utils MODULE pybind11_protobuf/proto_utils.cc
+  pybind11_protobuf/proto_utils.h)
+
+target_link_libraries(
+  pybind11_proto_utils PRIVATE absl::strings protobuf::libprotobuf
+                               ${Python_LIBRARIES})
+
+target_include_directories(
+  pybind11_proto_utils PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS}
+                               ${protobuf_SOURCE_DIR} ${pybind11_INCLUDE_DIRS})
+
+# ============================================================================
+# pybind11_native_proto_caster shared library
+add_library(
+  pybind11_native_proto_caster SHARED
+  # bazel: pybind_library: native_proto_caster
+  pybind11_protobuf/native_proto_caster.h
+  # bazel: pybind_library: enum_type_caster
+  pybind11_protobuf/enum_type_caster.h
+  # bazel: pybind_library: proto_cast_util
+  pybind11_protobuf/proto_cast_util.cc
+  pybind11_protobuf/proto_cast_util.h
+  pybind11_protobuf/proto_caster_impl.h
+  # bazel: cc_library::check_unknown_fields
+  pybind11_protobuf/check_unknown_fields.cc
+  pybind11_protobuf/check_unknown_fields.h)
+
+target_link_libraries(
+  pybind11_native_proto_caster
+  absl::flat_hash_map
+  absl::flat_hash_set
+  absl::hash
+  absl::strings
+  absl::optional
+  protobuf::libprotobuf
+  pybind11::pybind11
+  ${Python_LIBRARIES})
+
+target_include_directories(
+  pybind11_native_proto_caster
+  PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS} ${protobuf_SOURCE_DIR}
+          ${pybind11_INCLUDE_DIRS})
+
+# ============================================================================
+# pybind11_wrapped_proto_caster shared library
+add_library(
+  pybind11_wrapped_proto_caster SHARED
+  # bazel: pybind_library: wrapped_proto_caster
+  pybind11_protobuf/wrapped_proto_caster.h
+  # bazel: pybind_library: proto_cast_util
+  pybind11_protobuf/proto_cast_util.cc
+  pybind11_protobuf/proto_cast_util.h
+  pybind11_protobuf/proto_caster_impl.h
+  # bazel: cc_library: check_unknown_fields
+  pybind11_protobuf/check_unknown_fields.cc
+  pybind11_protobuf/check_unknown_fields.h)
+
+target_link_libraries(
+  pybind11_wrapped_proto_caster
+  absl::flat_hash_map
+  absl::flat_hash_set
+  absl::hash
+  absl::strings
+  absl::optional
+  protobuf::libprotobuf
+  pybind11::pybind11
+  ${Python_LIBRARIES})
+
+target_include_directories(
+  pybind11_wrapped_proto_caster
+  PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS} ${protobuf_SOURCE_DIR}
+          ${pybind11_INCLUDE_DIRS})
+
+# TODO set defines PYBIND11_PROTOBUF_ENABLE_PYPROTO_API see: bazel:
+# pybind_library: proto_cast_util
+
+# bazel equivs. checklist
+#
+# bazel: pybind_library: enum_type_caster - enum_type_caster.h
+#
+# bazel: pybind_library: native_proto_caster - native_proto_caster.h
+#
+# check_unknown_fields enum_type_caster proto_cast_util
+#
+# bazel: pybind_library: proto_cast_util - proto_cast_util.cc -
+# proto_cast_util.h - proto_caster_impl.h
+#
+# check_unknown_fields
+#
+# bazel: pybind_library: wrapped_proto_caster - wrapped_proto_caster.h
+#
+# proto_cast_util
+#
diff --git a/cmake/dependencies/CMakeLists.txt b/cmake/dependencies/CMakeLists.txt
new file mode 100644
index 0000000..ea302c9
--- /dev/null
+++ b/cmake/dependencies/CMakeLists.txt
@@ -0,0 +1,60 @@
+include(FetchContent)
+
+# ============================================================================
+# Declare all dependencies first
+
+if(BUILD_absl)
+  FetchContent_Declare(
+    absl
+    GIT_REPOSITORY "https://github.com/abseil/abseil-cpp.git"
+    GIT_TAG "20220623.1")
+endif()
+
+# https://stackoverflow.com/questions/63309544/cmake-protobuf-external-to-application-code
+# https://cmake.org/cmake/help/latest/policy/CMP0077.html
+# https://gitlab.kitware.com/cmake/cmake/-/merge_requests/7565/diffs
+if(BUILD_protobuf)
+  set(protobuf_BUILD_TESTS
+      OFF
+      CACHE INTERNAL "")
+  FetchContent_Declare(
+    protobuf
+    GIT_REPOSITORY "https://github.com/protocolbuffers/protobuf.git"
+    GIT_TAG "v21.5"
+    GIT_SUBMODULES "")
+endif()
+
+if(BUILD_pybind11)
+  set(PYBIND11_TEST OFF)
+  FetchContent_Declare(
+    pybind11
+    GIT_REPOSITORY "https://github.com/pybind/pybind11.git"
+    GIT_TAG "v2.10.1")
+endif()
+
+# ============================================================================
+# Make dependencies avaialble
+
+if(BUILD_absl)
+  message(CHECK_START "Fetching Abseil-cpp")
+  list(APPEND CMAKE_MESSAGE_INDENT "  ")
+  FetchContent_MakeAvailable(absl)
+  list(POP_BACK CMAKE_MESSAGE_INDENT)
+  message(CHECK_PASS "fetched")
+endif()
+
+if(BUILD_protobuf)
+  message(CHECK_START "Fetching protobuf")
+  list(APPEND CMAKE_MESSAGE_INDENT "  ")
+  FetchContent_MakeAvailable(protobuf)
+  list(POP_BACK CMAKE_MESSAGE_INDENT)
+  message(CHECK_PASS "fetched")
+endif()
+
+if(BUILD_pybind11)
+  message(CHECK_START "Fetching pybind11")
+  list(APPEND CMAKE_MESSAGE_INDENT "  ")
+  FetchContent_MakeAvailable(pybind11)
+  list(POP_BACK CMAKE_MESSAGE_INDENT)
+  message(CHECK_PASS "fetched")
+endif()
diff --git a/cmake/deps.cmake b/cmake/deps.cmake
new file mode 100644
index 0000000..5db89a7
--- /dev/null
+++ b/cmake/deps.cmake
@@ -0,0 +1,11 @@
+if(NOT BUILD_absl)
+  find_package(absl REQUIRED)
+endif()
+
+if(NOT BUILD_protobuf)
+  find_package(protobuf REQUIRED)
+endif()
+
+if(NOT BUILD_pybind11)
+  find_package(pybind11 REQUIRED)
+endif()
diff --git a/pybind11_protobuf/tests/CMakeLists.txt b/pybind11_protobuf/tests/CMakeLists.txt
new file mode 100644
index 0000000..afca562
--- /dev/null
+++ b/pybind11_protobuf/tests/CMakeLists.txt
@@ -0,0 +1,33 @@
+# ============================================================================
+# tests
+# ============================================================================
+
+# ============================================================================
+# generate protobuf bindings
+
+set(Protobuf_IMPORT_DIRS
+    "${CMAKE_CURRENT_SOURCE_DIR}/../../..;${Protobuf_IMPORT_DIRS}")
+
+protobuf_generate_cpp(
+  PROTO_SRCS PROTO_HDRS
+  # extension.proto
+  test.proto)
+
+protobuf_generate_python(
+  PROTO_PYS
+  # extension.proto
+  test.proto)
+
+# ============================================================================
+# adding a custom target forces CMake to generate the bindings
+
+add_custom_target(pybind11_test_proto_cpp ALL DEPENDS ${PROTO_SRCS}
+                                                      ${PROTO_HDRS})
+add_custom_target(pybind11_test_proto_python ALL DEPENDS ${PROTO_PYS})
+
+# ============================================================================
+# generate protobuf library
+
+add_library(pybind11_test_proto ${PROTO_SRCS} ${PROTO_HDR})
+
+target_include_directories(pybind11_test_proto PUBLIC ${Protobuf_INCLUDE_DIR})