diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index ae243762f..d88de6246 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -3,17 +3,109 @@ name: Windows
 on: [push, pull_request]
 
 jobs:
+  mingw:
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up MinGW
+        uses: egor-tensin/setup-mingw@v2
+        with:
+          platform: x64
+      - name: cmake
+        run: cmake -S . -B build -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+      - name: build
+        run: cmake --build build --parallel 10
+      - name: test
+        run: cd build ; ctest -j 10 -C Debug --output-on-failure
+
+  mingw_win32:
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up MinGW
+        uses: egor-tensin/setup-mingw@v2
+        with:
+          platform: x86
+      - name: cmake
+        run: cmake -S . -B build -G "MinGW Makefiles" -DCMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+      - name: build
+        run: cmake --build build --parallel 10
+      - name: test
+        run: cd build ; ctest -j 10 -C Debug --output-on-failure
+
+  msvc2017:
+    runs-on: windows-2016
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: cmake
+      run: cmake -S . -B build -G "Visual Studio 15 2017" -DJSON_BuildTests=On
+    - name: build
+      run: cmake --build build --config Release --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 -C Release --output-on-failure
+
+  msvc2017_latest:
+    runs-on: windows-2016
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: cmake
+      run: cmake -S . -B build -G "Visual Studio 15 2017" -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8"
+    - name: build
+      run: cmake --build build --config Release --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 -C Release --output-on-failure
+
+  msvc2017_win32:
+    runs-on: windows-2016
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: cmake
+      run: cmake -S . -B build -G "Visual Studio 15 2017" -A "Win32" -DJSON_BuildTests=On
+    - name: build
+      run: cmake --build build --config Release --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 -C Release --output-on-failure
+
   msvc2019:
     runs-on: windows-latest
 
     steps:
     - uses: actions/checkout@v2
     - name: cmake
-      run: cmake -S . -B build -G "Visual Studio 16 2019" -D CMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+      run: cmake -S . -B build -G "Visual Studio 16 2019" -DJSON_BuildTests=On
     - name: build
-      run: cmake --build build --parallel 10
+      run: cmake --build build --config Release --parallel 10
     - name: test
-      run: cd build ; ctest -j 10 -C Debug --exclude-regex "test-unicode" --output-on-failure
+      run: cd build ; ctest -j 10 -C Release --output-on-failure
+
+  msvc2019_latest:
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: cmake
+      run: cmake -S . -B build -G "Visual Studio 16 2019" -DJSON_BuildTests=On -DCMAKE_CXX_FLAGS="/permissive- /std:c++latest /utf-8"
+    - name: build
+      run: cmake --build build --config Release --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 -C Release --output-on-failure
+
+  msvc2019_win32:
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: cmake
+      run: cmake -S . -B build -G "Visual Studio 16 2019" -A "Win32" -DJSON_BuildTests=On
+    - name: build
+      run: cmake --build build --config Release --parallel 10
+    - name: test
+      run: cd build ; ctest -j 10 -C Release --output-on-failure
 
   clang10:
     runs-on: windows-latest
@@ -29,6 +121,20 @@ jobs:
       - name: test
         run: cd build ; ctest -j 10 -C Debug --exclude-regex "test-unicode" --output-on-failure
 
+  clang11:
+    runs-on: windows-latest
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: install Clang
+        run: curl -fsSL -o LLVM11.exe https://github.com/llvm/llvm-project/releases/download/llvmorg-11.0.0/LLVM-11.0.0-win64.exe ; 7z x LLVM11.exe -y -o"C:/Program Files/LLVM"
+      - name: cmake
+        run: cmake -S . -B build -DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" -G"MinGW Makefiles" -DCMAKE_BUILD_TYPE=Debug -DJSON_BuildTests=On
+      - name: build
+        run: cmake --build build --parallel 10
+      - name: test
+        run: cd build ; ctest -j 10 -C Debug --exclude-regex "test-unicode" --output-on-failure
+
   clang-cl-10-x64:
     runs-on: windows-latest
 
diff --git a/appveyor.yml b/appveyor.yml
index 5836f88d0..d525c3a54 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -34,24 +34,6 @@ environment:
       CMAKE_OPTIONS: ""
       GENERATOR: Visual Studio 16 2019
 
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      configuration: Debug
-      COMPILER: mingw
-      platform: x86
-      CXX_FLAGS: ""
-      LINKER_FLAGS: ""
-      CMAKE_OPTIONS: ""
-      GENERATOR: Ninja
-
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      configuration: Release
-      COMPILER: mingw
-      platform: x86
-      CXX_FLAGS: ""
-      LINKER_FLAGS: ""
-      CMAKE_OPTIONS: ""
-      GENERATOR: Ninja
-
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       configuration: Release
       platform: x86
@@ -85,14 +67,6 @@ environment:
       CMAKE_OPTIONS: "-DJSON_ImplicitConversions=OFF"
       GENERATOR: Visual Studio 16 2019
 
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-      configuration: Release
-      platform: x64
-      CXX_FLAGS: ""
-      LINKER_FLAGS: ""
-      CMAKE_OPTIONS: ""
-      GENERATOR: Visual Studio 16 2019
-
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       configuration: Release
       platform: x64
@@ -122,18 +96,13 @@ init:
   - msbuild /version
 
 install:
-  - if "%COMPILER%"=="mingw"  appveyor DownloadFile https://github.com/ninja-build/ninja/releases/download/v1.6.0/ninja-win.zip -FileName ninja.zip
-  - if "%COMPILER%"=="mingw"  7z x ninja.zip -oC:\projects\deps\ninja > nul
-  - if "%COMPILER%"=="mingw"  set PATH=C:\projects\deps\ninja;%PATH%
-  - if "%COMPILER%"=="mingw"  set PATH=C:\mingw-w64\x86_64-7.3.0-posix-seh-rt_v5-rev0\mingw64\bin;%PATH%
-  - if "%COMPILER%"=="mingw"  g++ --version
   - if "%platform%"=="x86"    set GENERATOR_PLATFORM=Win32
 
 before_build:
   # for with_win_header build, inject the inclusion of Windows.h to the single-header library
   - ps: if ($env:name -Eq "with_win_header") { $header_path = "single_include\nlohmann\json.hpp" }
   - ps: if ($env:name -Eq "with_win_header") { "#include <Windows.h>`n" + (Get-Content $header_path | Out-String) | Set-Content $header_path }
-  - if "%GENERATOR%"=="Ninja" (cmake . -G "%GENERATOR%" -DCMAKE_BUILD_TYPE="%configuration%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_EXE_LINKER_FLAGS="%LINKER_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On "%CMAKE_OPTIONS%") else (cmake . -G "%GENERATOR%" -A "%GENERATOR_PLATFORM%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_EXE_LINKER_FLAGS="%LINKER_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On "%CMAKE_OPTIONS%")
+  - cmake . -G "%GENERATOR%" -A "%GENERATOR_PLATFORM%" -DCMAKE_CXX_FLAGS="%CXX_FLAGS%" -DCMAKE_EXE_LINKER_FLAGS="%LINKER_FLAGS%" -DCMAKE_IGNORE_PATH="C:/Program Files/Git/usr/bin" -DJSON_BuildTests=On "%CMAKE_OPTIONS%"
 
 build_script:
   - cmake --build . --config "%configuration%"