diff --git a/.github/workflows/macosx_cpn.yml b/.github/workflows/macosx_cpn.yml
new file mode 100644
index 000000000..d8307c14b
--- /dev/null
+++ b/.github/workflows/macosx_cpn.yml
@@ -0,0 +1,100 @@
+name: MacOSX Companion
+
+on:
+  push:
+    branches:
+    - 'main'
+    paths:
+    - '.github/workflow/macosx_cpn.yml'
+    - 'companion/**'
+    - 'tools/build-companion-nightly.sh'
+  pull_request:
+    branches:
+    - 'main'
+    paths:
+    - '.github/workflow/macosx_cpn.yml'
+    - 'companion/**'
+    - 'tools/build-companion-nightly.sh'
+
+  workflow_dispatch:
+
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+  QT_VERSION: "5.12.9"
+
+jobs:
+  build:
+    # The CMake configure and build commands are platform agnostic and should work equally
+    # well on Windows or Mac.  You can convert this to a matrix build if you need
+    # cross-platform coverage.
+    # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
+    runs-on: macos-latest
+
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v2
+        with:
+          submodules: recursive
+
+      - name: Create Build Environment
+        # Some projects don't allow in-source building, so create a separate build directory
+        # We'll use this as our working directory for all subsequent commands
+        run: cmake -E make_directory ${{github.workspace}}/build
+
+      - name: Install Qt
+        uses: jurplel/install-qt-action@v2
+        with:
+          version: ${{ env.QT_VERSION }}
+
+      - name: Install dependencies
+        run: python -m pip install --upgrade pip Pillow
+
+      - name: Install ARM toolchain
+        uses: fiam/arm-none-eabi-gcc@v1
+        with:
+          release: '10-2020-q4'
+
+      - name: Install dfu-util
+        run:   wget https://downloads.sourceforge.net/project/dfu-util/dfu-util-0.9.tar.gz &&
+          tar xfv dfu-util-0.9.tar.gz &&
+          cd dfu-util-0.9 &&
+          ./configure &&
+          make install
+
+      - name: Install libusb
+        run:   wget https://github.com/libusb/libusb/releases/download/v1.0.20/libusb-1.0.20.tar.bz2 &&
+          export MACOSX_DEPLOYMENT_TARGET=10.9 &&
+          tar xfv libusb-1.0.20.tar.bz2 &&
+          cd libusb-1.0.20 &&
+          ./configure &&
+          make install &&
+          cd ..
+
+      - name: Install libsdl
+        run:   wget https://www.libsdl.org/release/SDL-1.2.15.tar.gz &&
+          tar xfv SDL-1.2.15.tar.gz &&
+          export MACOSX_DEPLOYMENT_TARGET=10.9 &&
+          cd SDL-1.2.15 &&
+          wget 'https://bugzilla-attachments.libsdl.org/attachment.cgi?id=1320' -O patch1 &&
+          wget 'https://bugzilla-attachments.libsdl.org/attachment.cgi?id=1324' -O patch2 &&
+          wget 'https://hg.libsdl.org/SDL/raw-rev/91ad7b43317a' -O patch3 &&
+          patch -p1 < patch1 &&
+          patch -p1 < patch2 &&
+          patch -p1 < patch3 &&
+          ./configure --without-x &&
+          make install
+
+      - name: Build
+        working-directory: ${{github.workspace}}
+        shell: bash
+        run: |
+          mkdir output && \
+          tools/build-companion-nightly.sh $(pwd) $(pwd)/output/
+
+      - name: Archive production artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: companion-nightly
+          path:  ${{github.workspace}}/output
+          retention-days: 15