diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cd7a358..3a293b1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -7,8 +7,6 @@ on:
     branches: [main]
 
 jobs:
-  # Windows/MSVC is intentionally out of scope here - the Boost.Asio/Beast + current CMake setup
-  # would be a bigger lift than adding another *nix compiler, so it's left for a follow-up.
   build-and-test:
     strategy:
       fail-fast: false
@@ -23,9 +21,16 @@ jobs:
           - os: macos-latest
             cc: clang
             cxx: clang++
+          - os: windows-latest
+            cc: msvc
+            cxx: msvc
     name: Build & Test (${{ matrix.os }}, ${{ matrix.cc }})
     runs-on: ${{ matrix.os }}
 
+    defaults:
+      run:
+        shell: bash
+
     env:
       VCPKG_ROOT: ${{ github.workspace }}/vcpkg
       VCPKG_DEFAULT_BINARY_CACHE: ${{ github.workspace }}/vcpkg-bincache
@@ -55,11 +60,17 @@ jobs:
       - name: Configure (CMake preset "default")
         run: cmake --preset default -DHYPERLIQUID_WARNINGS_AS_ERRORS=ON
 
+      # --config/-C are no-ops on the single-config Makefiles generator Linux/macOS use, and
+      # select Release on Windows' multi-config Visual Studio generator. --parallel with no
+      # number is unbounded on the Makefiles generator (bare `make -j`, not "one job per core") -
+      # this repo's ~80 independent test/example targets all become ready at once after the
+      # shared library links, and firing all of them at once reliably OOMs a standard hosted
+      # runner (reproduced locally under a matching memory cgroup - not flakiness).
       - name: Build
-        run: cmake --build build -j"$(getconf _NPROCESSORS_ONLN)"
+        run: cmake --build build --config Release --parallel 4
 
       - name: Test
-        run: ctest --test-dir build --output-on-failure
+        run: ctest --test-dir build -C Release --output-on-failure
 
   sanitize:
     name: Sanitizers (ASan+UBSan, ubuntu-latest, gcc)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d0ec630..8dc3f99 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -98,6 +98,22 @@ if(NOT MSVC)
     target_compile_options(hyperliquid-sdk PRIVATE ${HYPERLIQUID_WARNING_FLAGS})
 endif()
 
+if(WIN32)
+    # Boost.Asio pulls in <windows.h> transitively; NOMINMAX/WIN32_LEAN_AND_MEAN avoid its
+    # min/max macros colliding with std::min/std::max and cut unneeded header bloat.
+    # _WIN32_WINNT pins the target Windows API version Asio otherwise has to guess at (with a
+    # build warning) - 0x0A00 is Windows 10, matching CI's windows-latest runner.
+    target_compile_definitions(hyperliquid-sdk PUBLIC NOMINMAX WIN32_LEAN_AND_MEAN _WIN32_WINNT=0x0A00)
+    target_link_libraries(hyperliquid-sdk PUBLIC ws2_32 mswsock)
+endif()
+
+if(MSVC)
+    # /EHsc: MSVC needs the exception model spelled out explicitly (this codebase throws/catches
+    # throughout). /bigobj: Boost.Asio/Beast's heavy template instantiation blows past MSVC's
+    # default COFF section-table limit (C1128) in translation units like WebsocketRunner.cpp.
+    target_compile_options(hyperliquid-sdk PUBLIC /EHsc /bigobj)
+endif()
+
 if(HYPERLIQUID_SANITIZE)
     target_compile_options(hyperliquid-sdk PUBLIC ${HYPERLIQUID_SANITIZE_FLAGS})
     target_link_options(hyperliquid-sdk PUBLIC ${HYPERLIQUID_SANITIZE_FLAGS})
diff --git a/include/hyperliquid/types/ResponseTypes.h b/include/hyperliquid/types/ResponseTypes.h
index 0eb9b5a..8882ca2 100644
--- a/include/hyperliquid/types/ResponseTypes.h
+++ b/include/hyperliquid/types/ResponseTypes.h
@@ -3,6 +3,7 @@
 #include <array>
 #include <chrono>
 #include <cstdint>
+#include <ctime>
 #include <optional>
 #include <string>
 #include <string_view>
@@ -619,7 +620,11 @@ namespace hyperliquid
         tm.tm_min = std::stoi(s.substr(11, 2));
         tm.tm_sec = 0;
         tm.tm_isdst = 0;
+#ifdef _WIN32
+        std::time_t t = _mkgmtime(&tm);
+#else
         std::time_t t = timegm(&tm);
+#endif
         return std::chrono::system_clock::from_time_t(t);
     }