diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index e14e8e5..036bd0e 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,13 +11,15 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        configs: [Release, Debug]
+        configs: [Release]
         compiler: [gcc, clang]
+        flags: [-std=c++11, -std=c++17]
     steps:
     - name: Checkout
       uses: actions/checkout@v2.0.0
     - name: Build and test
       env:
         CXX: ${{ matrix.compiler }}
+        CXXFLAGS: ${{ matrix.flags }}
       run: |
-        mkdir build && cd build && cmake -DPHMAP_BUILD_TESTS=ON -DPHMAP_BUILD_EXAMPLES=ON -DCMAKE_CXX_COMPILER=${COMPILER} -DCXXFLAGS="${CXX_FLAGS}" .. && cmake --build . && make test
+        mkdir build && cd build && cmake -DPHMAP_BUILD_TESTS=ON -DPHMAP_BUILD_EXAMPLES=ON -DCMAKE_CXX_COMPILER=${CXX} -DCXXFLAGS="${CXXFLAGS}" .. && cmake --build . && make test