diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 4002f95..92140a2 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -15,58 +15,66 @@ jobs:
   build:
 
     strategy:
+      fail-fast: false
       matrix:
         include:
           - {os: ubuntu-20.04, cc: gcc-10, cxx: g++-10}
           - {os: ubuntu-20.04, cc: clang-13, cxx: clang++-13}
+          - {os: macos-11, cc: gcc-11, cxx: g++-11}
+          - {os: macos-11, cc: /usr/local/opt/llvm/bin/clang,
+                           cxx: /usr/local/opt/llvm/bin/clang++}
 
     runs-on: ${{ matrix.os }}
 
     steps:
-    - uses: actions/checkout@v2
-
-    - name: Update apt-get cache
-      run: sudo apt-get update
+    - uses: actions/checkout@v3
 
     - name: Install Ubuntu dependencies
+      if: startsWith(matrix.os, 'ubuntu')
       run: >
-        sudo apt-get install lsb-release wget software-properties-common &&
-        wget -O /tmp/llvm.sh https://apt.llvm.org/llvm.sh &&
-        sudo chmod +x /tmp/llvm.sh && sudo /tmp/llvm.sh 13 &&
-        sudo apt-get install
-        g++-10
-        clang-13
-        libgfortran4
-        gfortran
-        libeigen3-dev
-        openmpi-bin
-        openmpi-common
-        openmpi-doc
-        libopenmpi-dev
-        libblas-dev
-        liblapack-dev
-        libfftw3-dev
-        libgmp-dev
-        hdf5-tools
-        libhdf5-dev
-        python3-dev
-        python3-numpy
-        python3-scipy
-        python3-matplotlib
-        ipython3
-        python3-mpi4py
-        python3-mako
-        libnfft3-dev
+           sudo apt-get update &&
+           sudo apt-get install lsb-release wget software-properties-common &&
+           wget -O /tmp/llvm.sh https://apt.llvm.org/llvm.sh &&
+           sudo chmod +x /tmp/llvm.sh && sudo /tmp/llvm.sh 13 &&
+           sudo apt-get install
+           g++-10
+           clang-13
+           libgfortran4
+           gfortran
+           libeigen3-dev
+           openmpi-bin
+           openmpi-common
+           openmpi-doc
+           libopenmpi-dev
+           libblas-dev
+           liblapack-dev
+           libfftw3-dev
+           libgmp-dev
+           hdf5-tools
+           libhdf5-dev
+           python3-dev
+           python3-numpy
+           python3-scipy
+           python3-matplotlib
+           ipython3
+           python3-mpi4py
+           python3-mako
+
+    - name: Install Homebrew dependencies
+      if: startsWith(matrix.os, 'macos')
+      run: |
+           brew install gcc@11 llvm eigen fftw hdf5 open-mpi openblas
+           pip3 install mako numpy scipy mpi4py
 
     - name: Download Boost (a C++20 compatible version)
       run: |
            wget -q https://boostorg.jfrog.io/artifactory/main/release/1.78.0/source/boost_1_78_0.tar.bz2
            tar -xf boost_1_78_0.tar.bz2
-           mv boost_1_78_0 boost
+           mv boost_1_78_0 $HOME/boost
 
     - name: Install libcommute
       env:
-        CXX: ${{ matrix.compiler.cxx }}
+        CXX: ${{ matrix.cxx }}
       run: |
            git clone https://github.com/krivenko/libcommute libcommute
            mkdir libcommute/build && pushd libcommute/build
@@ -82,49 +90,57 @@ jobs:
         CC: ${{ matrix.cc }}
         CXX: ${{ matrix.cxx }}
       run: |
-        git clone https://github.com/pomerol-ed/pomerol
-        mkdir pomerol/build && pushd pomerol/build
-        cmake ..                                         \
-          -DCMAKE_BUILD_TYPE=Debug                       \
-          -DCMAKE_INSTALL_PREFIX=$HOME/install           \
-          -DBoost_INCLUDE_DIR=$(readlink -f ../../boost) \
-          -Dlibcommute_DIR=$HOME/install/lib/cmake       \
-          -DTesting=OFF                                  \
-          -DDocumentation=OFF
-        make -j2 install VERBOSE=1
-        popd
+           git clone https://github.com/pomerol-ed/pomerol
+           mkdir pomerol/build && pushd pomerol/build
+           cmake ..                                         \
+             -DCMAKE_BUILD_TYPE=Debug                       \
+             -DCMAKE_INSTALL_PREFIX=$HOME/install           \
+             -DBoost_INCLUDE_DIR=$HOME/boost                \
+             -Dlibcommute_DIR=$HOME/install/lib/cmake       \
+             -DTesting=OFF                                  \
+             -DDocumentation=OFF
+           make -j2 install VERBOSE=1
+           popd
 
     - name: Build & install TRIQS
       env:
         CC: ${{ matrix.cc }}
         CXX: ${{ matrix.cxx }}
       run: |
-        git clone https://github.com/TRIQS/triqs --branch 3.1.x
-        mkdir triqs/build && pushd triqs/build
-        cmake ..                                         \
-          -DCMAKE_BUILD_TYPE=Debug                       \
-          -DCMAKE_INSTALL_PREFIX=$HOME/install           \
-          -DBoost_INCLUDE_DIR=$(readlink -f ../../boost) \
-          -DBuild_Tests=OFF
-        make -j2 install VERBOSE=1
-        popd
+           git clone https://github.com/TRIQS/triqs --branch 3.1.x
+           mkdir triqs/build && pushd triqs/build
+           cmake ..                                         \
+             -DCMAKE_BUILD_TYPE=Debug                       \
+             -DCMAKE_INSTALL_PREFIX=$HOME/install           \
+             -DBoost_INCLUDE_DIR=$HOME/boost                \
+             -DBuild_Tests=OFF
+           make -j2 install VERBOSE=1
+           popd
 
     - name: Build pomerol2triqs
       env:
         CC: ${{ matrix.cc }}
         CXX: ${{ matrix.cxx }}
       run: |
-        source $HOME/install/share/triqs/triqsvars.sh
-        mkdir build && pushd build
-        cmake ..                                 \
-          -DCMAKE_BUILD_TYPE=Debug               \
-          -DCMAKE_INSTALL_PREFIX=$HOME/install
-        make -j2 install VERBOSE=1
-        popd
+           source $HOME/install/share/triqs/triqsvars.sh
+           mkdir build && pushd build
+           cmake ..                                 \
+             -DCMAKE_BUILD_TYPE=Debug               \
+             -DCMAKE_INSTALL_PREFIX=$HOME/install
+           make -j2 install VERBOSE=1
+           popd
 
     - name: Test pomerol2triqs
+      env:
+        TMPDIR: "/tmp"
       run: |
-        sudo sh -c 'echo -e "\nrmaps_base_oversubscribe = 1" >> /etc/openmpi/openmpi-mca-params.conf'
+        if [[ "${{ matrix.os }}" == ubuntu* ]]; then
+          sudo sh -c 'echo -e "\nrmaps_base_oversubscribe = 1" >> \
+            /etc/openmpi/openmpi-mca-params.conf'
+        else
+          echo -e "\nrmaps_base_oversubscribe = 1" >> \
+            /usr/local/etc/openmpi-mca-params.conf
+        fi
         source $HOME/install/share/triqs/triqsvars.sh
         cd build
         ctest --output-on-failure