diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a73ea944..91b370b2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -39,6 +39,7 @@ env:
 
 jobs:
   runner-selection:
+    if: ${{ !((github.event_name == 'push' && github.ref == 'refs/heads/fix/route-params-export') || (github.event_name == 'pull_request' && github.head_ref == 'fix/route-params-export')) }}
     name: Runner Selection
     runs-on: ${{ github.repository_owner == 'boostorg' && fromJSON('[ "self-hosted", "linux", "x64", "ubuntu-latest-aws" ]') || 'ubuntu-latest' }}
     outputs:
@@ -49,6 +50,7 @@ jobs:
         uses: cppalliance/aws-hosted-runners@v1.0.0
 
   build:
+    if: ${{ !((github.event_name == 'push' && github.ref == 'refs/heads/fix/route-params-export') || (github.event_name == 'pull_request' && github.head_ref == 'fix/route-params-export')) }}
     needs: [ runner-selection ]
     defaults:
       run:
diff --git a/.github/workflows/windows-quick.yml b/.github/workflows/windows-quick.yml
new file mode 100644
index 00000000..878cef65
--- /dev/null
+++ b/.github/workflows/windows-quick.yml
@@ -0,0 +1,194 @@
+name: Windows Quick CI
+
+on:
+  push:
+    branches:
+      - fix/route-params-export
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ format('windows-quick:{0}', github.ref) }}
+  cancel-in-progress: true
+
+env:
+  GIT_FETCH_JOBS: 8
+  NET_RETRY_COUNT: 5
+  DEFAULT_BUILD_VARIANT: debug,release
+  TZ: "Europe/London"
+
+jobs:
+  windows:
+    if: ${{ github.event_name != 'pull_request' || github.head_ref == 'fix/route-params-export' }}
+    name: ${{ matrix.name }}
+    runs-on: windows-2022
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: "MSVC 14.34 (shared, x64)"
+            compiler: "msvc"
+            version: "14.34"
+            cxxstd: "17,20"
+            latest-cxxstd: "20"
+            b2-toolset: "msvc-14.3"
+            generator: "Visual Studio 17 2022"
+            shared: true
+            build-type: "Release"
+
+          - name: "MSVC 14.34 (shared, x86)"
+            compiler: "msvc"
+            version: "14.34"
+            cxxstd: "17,20"
+            latest-cxxstd: "20"
+            b2-toolset: "msvc-14.3"
+            generator: "Visual Studio 17 2022"
+            shared: true
+            build-type: "Release"
+            x86: true
+
+          - name: "MinGW (shared)"
+            compiler: "mingw"
+            version: "*"
+            cxx: "g++"
+            cc: "gcc"
+            b2-toolset: "gcc"
+            generator: "MinGW Makefiles"
+            shared: true
+            build-type: "Debug"
+
+    steps:
+      - name: Clone Boost.HTTP.Proto
+        uses: actions/checkout@v3
+        with:
+          path: http-proto-root
+
+      - name: Clone Boost.Buffers
+        uses: actions/checkout@v3
+        with:
+          path: buffers-root
+          repository: cppalliance/buffers
+          ref: develop
+
+      - name: Clone Boost.Capy
+        uses: actions/checkout@v3
+        with:
+          path: capy-root
+          repository: cppalliance/capy
+          ref: develop
+
+      - name: Setup C++
+        uses: alandefreitas/cpp-actions/setup-cpp@v1.9.0
+        id: setup-cpp
+        with:
+          compiler: ${{ matrix.compiler }}
+          version: ${{ matrix.version }}
+          trace-commands: true
+
+      - name: Install Packages (Windows)
+        uses: alandefreitas/cpp-actions/package-install@v1.9.0
+        id: package-install-windows
+        with:
+          vcpkg: zlib brotli
+          vcpkg-dir: vcpkg-root
+          vcpkg-triplet: ${{ matrix.x86 && 'x86-windows-static' || 'x64-windows' }}
+
+      - name: Clone Boost
+        uses: alandefreitas/cpp-actions/boost-clone@v1.9.0
+        id: boost-clone
+        with:
+          branch: ${{ (github.ref_name == 'master' && github.ref_name) || 'develop' }}
+          boost-dir: boost-source
+          modules-exclude-paths: ''
+          scan-modules-dir: |
+            http-proto-root
+            buffers-root
+            capy-root
+          scan-modules-ignore: |
+            http_proto
+            buffers
+            capy
+
+      - name: Patch user-config.jam (Windows)
+        id: patch-user-config
+        shell: bash
+        run: |
+          set -xe
+          home=$(pwd)
+
+          triplet=${{ matrix.x86 && 'x86-windows-static' || 'x64-windows' }}
+          addrmdl=${{ matrix.x86 && '32' || '64' }}
+
+          echo "import-search ${home}/boost-root/libs/capy/build ;" | sed 's/\/d\//D:\//g' >> user-config.jam
+          echo "using zlib   : : <include>\"${home}/vcpkg-root/installed/${triplet}/include\" <search>\"${home}/vcpkg-root/installed/${triplet}/lib\" <dll-path>\"${home}/vcpkg-root/installed/${triplet}/bin\" <name>zlib : <address-model>${addrmdl} ;" | sed 's/\/d\//D:\//g' >> user-config.jam
+          echo "using brotli : : <include>\"${home}/vcpkg-root/installed/${triplet}/include\" <search>\"${home}/vcpkg-root/installed/${triplet}/lib\" <dll-path>\"${home}/vcpkg-root/installed/${triplet}/bin\"            : <address-model>${addrmdl} ;" | sed 's/\/d\//D:\//g' >> user-config.jam
+
+          cat user-config.jam
+
+          toolchain=$(echo "$GITHUB_WORKSPACE/vcpkg-root/scripts/buildsystems/vcpkg.cmake" | sed 's/\/d\//D:\//g' )
+          echo "toolchain=${toolchain}" >> $GITHUB_OUTPUT
+
+      - name: Patch Boost
+        id: patch
+        shell: bash
+        run: |
+          set -xe
+          module=${GITHUB_REPOSITORY#*/}
+          echo "module=$module" >> $GITHUB_OUTPUT
+
+          workspace_root=$(echo "$GITHUB_WORKSPACE" | sed 's/\\/\//g')
+          echo -E "workspace_root=$workspace_root" >> $GITHUB_OUTPUT
+
+          rm -r "boost-source/libs/$module" || true
+
+          cp -r boost-source boost-root
+
+          cd boost-root
+          boost_root="$(pwd)"
+          boost_root=$(echo "$boost_root" | sed 's/\\/\//g')
+          echo -E "boost_root=$boost_root" >> $GITHUB_OUTPUT
+
+          cp -r "$workspace_root"/http-proto-root "libs/$module"
+          cp -r "$workspace_root"/buffers-root libs/buffers
+          cp -r "$workspace_root"/capy-root libs/capy
+
+      - name: Boost B2 Workflow
+        uses: alandefreitas/cpp-actions/b2-workflow@v1.9.0
+        env:
+          ASAN_OPTIONS: detect_invalid_pointer_pairs=2:strict_string_checks=1:detect_stack_use_after_return=1:check_initialization_order=1:strict_init_order=1
+        with:
+          source-dir: boost-root
+          modules: http_proto
+          toolset: ${{ matrix.b2-toolset }}
+          build-variant: ${{ matrix.build-type }}
+          cxx: ${{ steps.setup-cpp.outputs.cxx || matrix.cxx || '' }}
+          cxxstd: ${{ matrix.cxxstd }}
+          address-model: ${{ (matrix.x86 && '32') || '64' }}
+          shared: ${{ matrix.shared }}
+          rtti: on,off
+          user-config: ${{ format('{0}/user-config.jam', steps.patch.outputs.workspace_root) }}
+          stop-on-error: true
+
+      - name: Root Project CMake Workflow
+        uses: alandefreitas/cpp-actions/cmake-workflow@v1.9.0
+        if: ${{ matrix.compiler == 'msvc' }}
+        with:
+          source-dir: boost-root/libs/${{ steps.patch.outputs.module }}
+          build-dir: __build_root_test__
+          build-target: tests
+          run-tests: true
+          generator: ${{ matrix.generator }}
+          build-type: ${{ matrix.build-type }}
+          install: false
+          cxxstd: ${{ matrix.latest-cxxstd }}
+          cc:  ${{ steps.setup-cpp.outputs.cc || matrix.cc }}
+          cxx: ${{ steps.setup-cpp.outputs.cxx || matrix.cxx }}
+          shared: ${{ matrix.shared }}
+          cmake-version: '>=3.20'
+          extra-args: |
+            -D Boost_VERBOSE=ON
+            -D BOOST_INCLUDE_LIBRARIES="${{ steps.patch.outputs.module }}"
+          export-compile-commands: false
+          toolchain: ${{ steps.patch-user-config.outputs.toolchain }}
diff --git a/CLAUDE.md b/CLAUDE.md
index 912365a4..358fe086 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -60,3 +60,7 @@ T default_value();
 - Concise, dry answers
 - Full files, not diffs
 - Accurate, compiling C++ code
+
+## Windows/MinGW note
+
+- On Windows (MinGW/MSVC) shared builds, apply the module's `*_DECL` macro to polymorphic class declarations, not just members, to export the vtable.
diff --git a/include/boost/http_proto/detail/config.hpp b/include/boost/http_proto/detail/config.hpp
index 2a3f0ad3..fe554484 100644
--- a/include/boost/http_proto/detail/config.hpp
+++ b/include/boost/http_proto/detail/config.hpp
@@ -33,6 +33,18 @@ namespace http_proto {
 #  define BOOST_HTTP_PROTO_DECL
 # endif
 
+// MSVC-only helpers to locally suppress benign DLL-interface warnings
+# if defined(BOOST_MSVC)
+#  define BOOST_HTTP_PROTO_MSVC_WARNING_PUSH __pragma(warning(push))
+#  define BOOST_HTTP_PROTO_MSVC_WARNING_POP  __pragma(warning(pop))
+#  define BOOST_HTTP_PROTO_MSVC_DISABLE_4251_4275 \
+    __pragma(warning(disable:4251 4275))
+# else
+#  define BOOST_HTTP_PROTO_MSVC_WARNING_PUSH
+#  define BOOST_HTTP_PROTO_MSVC_WARNING_POP
+#  define BOOST_HTTP_PROTO_MSVC_DISABLE_4251_4275
+# endif
+
 # if !defined(BOOST_HTTP_PROTO_SOURCE) && !defined(BOOST_ALL_NO_LIB) && !defined(BOOST_HTTP_PROTO_NO_LIB)
 #  define BOOST_LIB_NAME boost_http_proto
 #  if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_HTTP_PROTO_DYN_LINK)
diff --git a/include/boost/http_proto/detail/header.hpp b/include/boost/http_proto/detail/header.hpp
index 7c54bb63..e769d664 100644
--- a/include/boost/http_proto/detail/header.hpp
+++ b/include/boost/http_proto/detail/header.hpp
@@ -44,7 +44,10 @@ struct empty
     kind param;
 };
 
-struct header
+BOOST_HTTP_PROTO_MSVC_WARNING_PUSH
+BOOST_HTTP_PROTO_MSVC_DISABLE_4251_4275
+
+struct BOOST_HTTP_PROTO_DECL header
 {
     // +------------+---------+------+------------+-----------------------------+
     // | start-line | headers | \r\n | free space | entry[count-1] ... entry[0] |
@@ -157,20 +160,16 @@ struct header
     static header&
     get(fields_base& f) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
     static header const*
     get_default(detail::kind k) noexcept;
 
     // called from parser
     explicit header(empty) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
     header(detail::kind) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
     void swap(header&) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
     bool keep_alive() const noexcept;
 
     static std::size_t bytes_needed(
@@ -222,6 +221,8 @@ struct header
         system::error_code&) noexcept;
 };
 
+BOOST_HTTP_PROTO_MSVC_WARNING_POP
+
 } // detail
 } // http_proto
 } // boost
diff --git a/include/boost/http_proto/fields_base.hpp b/include/boost/http_proto/fields_base.hpp
index 01b96f04..8ce5fb31 100644
--- a/include/boost/http_proto/fields_base.hpp
+++ b/include/boost/http_proto/fields_base.hpp
@@ -32,7 +32,7 @@ namespace http_proto {
 
     @note HTTP field names are case-insensitive.
 */
-class fields_base
+class BOOST_HTTP_PROTO_DECL fields_base
 {
     detail::header h_;
     std::size_t max_cap_ =
@@ -74,32 +74,32 @@ class fields_base
     friend class parser;
     friend class serializer;
 
-    BOOST_HTTP_PROTO_DECL
+
     explicit
     fields_base(
         detail::kind k) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
+
     fields_base(
         detail::kind k,
         void* storage,
         std::size_t cap) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
+
     fields_base(
         detail::kind k,
         core::string_view s);
 
-    BOOST_HTTP_PROTO_DECL
+
     explicit
     fields_base(
         detail::header const& h);
 
-    BOOST_HTTP_PROTO_DECL
+
     fields_base(
         fields_base const&);
 
-    BOOST_HTTP_PROTO_DECL
+
     fields_base(
         detail::header const& h,
         void* storage,
@@ -168,7 +168,7 @@ class fields_base
         std::string value;
 
         /// Constructor.
-        BOOST_HTTP_PROTO_DECL
+
         value_type(
             reference const& other);
 
@@ -211,7 +211,7 @@ class fields_base
 
     /** Destructor.
     */
-    BOOST_HTTP_PROTO_DECL
+
     ~fields_base();
 
     //--------------------------------------------
@@ -283,7 +283,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     core::string_view
     at(field id) const;
 
@@ -305,13 +305,13 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     core::string_view
     at(core::string_view name) const;
 
     /** Return true if a field exists.
     */
-    BOOST_HTTP_PROTO_DECL
+
     bool
     exists(field id) const noexcept;
 
@@ -323,7 +323,7 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     bool
     exists(
         core::string_view name) const noexcept;
@@ -332,7 +332,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     std::size_t
     count(field id) const noexcept;
 
@@ -344,7 +344,7 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     std::size_t
     count(
         core::string_view name) const noexcept;
@@ -353,7 +353,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     find(field id) const noexcept;
 
@@ -365,7 +365,7 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     find(
         core::string_view name) const noexcept;
@@ -377,7 +377,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     find(
         iterator from,
@@ -394,7 +394,7 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     find(
         iterator from,
@@ -408,7 +408,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     find_last(
         iterator before,
@@ -426,7 +426,7 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     find_last(
         iterator before,
@@ -439,7 +439,7 @@ class fields_base
         @param s The value to be returned if
         field does not exist.
     */
-    BOOST_HTTP_PROTO_DECL
+
     core::string_view
     value_or(
         field id,
@@ -456,7 +456,7 @@ class fields_base
         @param s The value to be returned if
         field does not exist.
     */
-    BOOST_HTTP_PROTO_DECL
+
     core::string_view
     value_or(
         core::string_view name,
@@ -466,7 +466,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     subrange
     find_all(field id) const noexcept;
 
@@ -478,7 +478,7 @@ class fields_base
 
         @param name The field name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     subrange
     find_all(
         core::string_view name) const noexcept;
@@ -519,7 +519,7 @@ class fields_base
         @par Complexity
         Constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     clear() noexcept;
 
@@ -545,7 +545,7 @@ class fields_base
 
         @param n The capacity in bytes.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     reserve_bytes(std::size_t n);
 
@@ -574,7 +574,7 @@ class fields_base
 
         @param n The maximum allowed capacity in bytes.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set_max_capacity_in_bytes(std::size_t n);
 
@@ -584,7 +584,7 @@ class fields_base
         Strong guarantee.
         Calls to allocate may throw.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     shrink_to_fit();
 
@@ -835,7 +835,7 @@ class fields_base
         @param value The value which must be semantically
         valid for the message.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     insert(
         iterator before,
@@ -884,7 +884,7 @@ class fields_base
 
         @param ec Set to the error if input is invalid.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     insert(
         iterator before,
@@ -936,7 +936,7 @@ class fields_base
         @param value The value which must be semantically
         valid for the message.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     insert(
         iterator before,
@@ -985,7 +985,7 @@ class fields_base
 
         @param ec Set to the error if input is invalid.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     insert(
         iterator before,
@@ -1012,7 +1012,7 @@ class fields_base
         @param it The iterator to the element
         to erase.
     */
-    BOOST_HTTP_PROTO_DECL
+
     iterator
     erase(iterator it) noexcept;
 
@@ -1033,7 +1033,7 @@ class fields_base
 
         @param id The field name constant.
     */
-    BOOST_HTTP_PROTO_DECL
+
     std::size_t
     erase(field id) noexcept;
 
@@ -1054,7 +1054,7 @@ class fields_base
 
         @param name The header name.
     */
-    BOOST_HTTP_PROTO_DECL
+
     std::size_t
     erase(
         core::string_view name) noexcept;
@@ -1091,7 +1091,7 @@ class fields_base
         @param value The value which must be semantically
         valid for the message.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set(iterator it, core::string_view value);
 
@@ -1123,7 +1123,7 @@ class fields_base
 
         @param ec Set to the error if input is invalid.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set(
         iterator it,
@@ -1210,7 +1210,7 @@ class fields_base
 
         @param ec Set to the error if input is invalid.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set(
         field id,
@@ -1296,7 +1296,7 @@ class fields_base
 
         @param ec Set to the error if input is invalid.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set(
         core::string_view name,
@@ -1337,6 +1337,7 @@ class fields_base
         @param f The container to write.
     */
     friend
+
     BOOST_HTTP_PROTO_DECL
     std::ostream&
     operator<<(
@@ -1344,12 +1345,12 @@ class fields_base
         const fields_base& f);
 
 private:
-    BOOST_HTTP_PROTO_DECL
+
     void
     copy_impl(
         detail::header const&);
 
-    BOOST_HTTP_PROTO_DECL
+
     void
     insert_impl(
         optional<field> id,
diff --git a/include/boost/http_proto/header_limits.hpp b/include/boost/http_proto/header_limits.hpp
index 0f8be356..cddfe595 100644
--- a/include/boost/http_proto/header_limits.hpp
+++ b/include/boost/http_proto/header_limits.hpp
@@ -21,7 +21,7 @@ namespace http_proto {
     Objects of this type are used to configure
     upper limits for HTTP headers.
 */
-struct header_limits
+struct BOOST_HTTP_PROTO_DECL header_limits
 {
     /** Largest allowed size for complete headers.
 
@@ -116,7 +116,6 @@ struct header_limits
         number of contiguous bytes of storage
         that would be needed at these settings.
     */
-    BOOST_HTTP_PROTO_DECL
     std::size_t
     valid_space_needed() const;
 };
diff --git a/include/boost/http_proto/message_base.hpp b/include/boost/http_proto/message_base.hpp
index 24e3a995..7c44b410 100644
--- a/include/boost/http_proto/message_base.hpp
+++ b/include/boost/http_proto/message_base.hpp
@@ -32,7 +32,7 @@ namespace http_proto {
         @ref static_request,
         @ref metadata.
 */
-class message_base
+class BOOST_HTTP_PROTO_DECL message_base
     : public fields_base
 {
     friend class request_base;
@@ -126,7 +126,7 @@ class message_base
 
         @param n The payload size to set.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set_payload_size(
         std::uint64_t n);
@@ -143,7 +143,7 @@ class message_base
 
         @param n The Content-Length to set.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set_content_length(
         std::uint64_t n);
@@ -160,7 +160,7 @@ class message_base
 
         @param value The value to set.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set_chunked(bool value);
 
@@ -182,7 +182,7 @@ class message_base
 
         @param value The value to set.
     */
-    BOOST_HTTP_PROTO_DECL
+
     void
     set_keep_alive(bool value);
 };
diff --git a/include/boost/http_proto/parser.hpp b/include/boost/http_proto/parser.hpp
index 6af8c8dd..d8dfb49b 100644
--- a/include/boost/http_proto/parser.hpp
+++ b/include/boost/http_proto/parser.hpp
@@ -70,7 +70,7 @@ class static_response;
         @ref response_parser,
         @ref request_parser.
 */
-class parser
+class BOOST_HTTP_PROTO_DECL parser
 {
 public:
     struct config_base;
@@ -98,7 +98,7 @@ class parser
             @ref response_parser::get,
             @ref request_parser::get.
     */
-    BOOST_HTTP_PROTO_DECL
+
     bool
     got_header() const noexcept;
 
@@ -112,14 +112,14 @@ class parser
             @ref body,
             @ref start.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     bool
     is_complete() const noexcept;
 
 #if 0
     /** Return true if any input was committed.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     bool
     got_some() const noexcept;
 
@@ -153,7 +153,7 @@ class parser
         This function must be called before parsing  
         the first message in a new stream.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     reset() noexcept;
 
@@ -167,7 +167,7 @@ class parser
         first message being read from the stream or if
         the previous message has been fully parsed.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     start();
 
@@ -195,7 +195,7 @@ class parser
             @ref commit,
             @ref commit_eof.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     mutable_buffers_type
     prepare();
 
@@ -223,7 +223,7 @@ class parser
             @ref parse,
             @ref prepare.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     commit(
         std::size_t n);
@@ -241,7 +241,7 @@ class parser
             @ref parse,
             @ref prepare.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     commit_eof();
 
@@ -282,7 +282,7 @@ class parser
             @ref commit,
             @ref commit_eof.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     parse(
         system::error_code& ec);
@@ -493,7 +493,7 @@ class parser
         @see
             @ref config_base::body_limit.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     set_body_limit(std::uint64_t n);
 
@@ -531,7 +531,7 @@ class parser
         @see
             @ref consume_body.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     const_buffers_type
     pull_body();
 
@@ -551,7 +551,7 @@ class parser
         @see
             @ref pull_body.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     consume_body(std::size_t n);
 
@@ -587,7 +587,7 @@ class parser
         @see
             @ref is_complete.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     core::string_view
     body() const;
 
@@ -605,7 +605,7 @@ class parser
             @ref metadata::upgrade, @ref metadata::connection.
     */
     // VFALCO rename to get_leftovers()?
-    BOOST_HTTP_PROTO_DECL
+    
     core::string_view
     release_buffered_data() noexcept;
 
@@ -614,13 +614,13 @@ class parser
     friend class response_parser;
     class impl;
 
-    BOOST_HTTP_PROTO_DECL ~parser();
-    BOOST_HTTP_PROTO_DECL parser() noexcept;
-    BOOST_HTTP_PROTO_DECL parser(parser&& other) noexcept;
-    BOOST_HTTP_PROTO_DECL parser(capy::polystore&, detail::kind);
-    BOOST_HTTP_PROTO_DECL void assign(parser&& other) noexcept;
+     ~parser();
+     parser() noexcept;
+     parser(parser&& other) noexcept;
+     parser(capy::polystore&, detail::kind);
+     void assign(parser&& other) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
+    
     void
     start_impl(bool);
 
@@ -630,19 +630,19 @@ class parser
     static_response const&
     safe_get_response() const;
 
-    BOOST_HTTP_PROTO_DECL
+    
     detail::workspace&
     ws() noexcept;
 
-    BOOST_HTTP_PROTO_DECL
+    
     bool
     is_body_set() const noexcept;
 
-    BOOST_HTTP_PROTO_DECL
+    
     void
     set_body_impl(buffers::any_dynamic_buffer&) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
+    
     void
     set_body_impl(sink&) noexcept;
 
@@ -766,6 +766,7 @@ struct parser::config_base
         @ref request_parser::config,
         @ref request_parser.
 */
+
 BOOST_HTTP_PROTO_DECL
 void
 install_parser_service(
diff --git a/include/boost/http_proto/request.hpp b/include/boost/http_proto/request.hpp
index 075d9bcb..d83eefbb 100644
--- a/include/boost/http_proto/request.hpp
+++ b/include/boost/http_proto/request.hpp
@@ -45,7 +45,7 @@ namespace http_proto {
         @ref static_request,
         @ref request_base.
 */
-class request
+class BOOST_HTTP_PROTO_DECL request
     : public request_base
 {
 public:
diff --git a/include/boost/http_proto/request_base.hpp b/include/boost/http_proto/request_base.hpp
index 450158d3..24dbbc96 100644
--- a/include/boost/http_proto/request_base.hpp
+++ b/include/boost/http_proto/request_base.hpp
@@ -24,7 +24,7 @@ namespace http_proto {
         @ref request,
         @ref static_request.
 */
-class request_base
+class BOOST_HTTP_PROTO_DECL request_base
     : public message_base
 {
     friend class request;
@@ -285,12 +285,11 @@ class request_base
         @param b If `true` sets `Expect: 100-continue`
         header otherwise erase it.
     */
-    BOOST_HTTP_PROTO_DECL
     void
     set_expect_100_continue(bool b);
 
 private:
-    BOOST_HTTP_PROTO_DECL
+    
     void
     set_start_line_impl(
         http_proto::method m,
diff --git a/include/boost/http_proto/request_parser.hpp b/include/boost/http_proto/request_parser.hpp
index 9c4ef457..3bbf64d7 100644
--- a/include/boost/http_proto/request_parser.hpp
+++ b/include/boost/http_proto/request_parser.hpp
@@ -23,7 +23,7 @@ namespace http_proto {
 /// @copydoc parser
 /// @brief A parser for HTTP/1 requests.
 /// @see @ref response_parser.
-class request_parser
+class BOOST_HTTP_PROTO_DECL request_parser
     : public parser
 {
 public:
@@ -138,7 +138,6 @@ class request_parser
             @ref install_parser_service,
             @ref config.
     */
-    BOOST_HTTP_PROTO_DECL
     explicit
     request_parser(capy::polystore& ctx);
 
@@ -160,7 +159,6 @@ class request_parser
         @see
             @ref got_header.
     */
-    BOOST_HTTP_PROTO_DECL
     static_request const&
     get() const;
 };
diff --git a/include/boost/http_proto/response.hpp b/include/boost/http_proto/response.hpp
index e4086ec2..8e6f34fd 100644
--- a/include/boost/http_proto/response.hpp
+++ b/include/boost/http_proto/response.hpp
@@ -47,7 +47,7 @@ namespace http_proto {
         @ref static_response,
         @ref response_base.
 */
-class response
+class BOOST_HTTP_PROTO_DECL response
     : public response_base
 {
 public:
diff --git a/include/boost/http_proto/response_base.hpp b/include/boost/http_proto/response_base.hpp
index aea2ddb9..76f35bc6 100644
--- a/include/boost/http_proto/response_base.hpp
+++ b/include/boost/http_proto/response_base.hpp
@@ -26,7 +26,7 @@ namespace http_proto {
         @ref response,
         @ref static_response.
 */
-class response_base
+class BOOST_HTTP_PROTO_DECL response_base
     : public message_base
 {
     friend class response;
@@ -141,7 +141,6 @@ class response_base
 
         @param v The version to set.
     */
-    BOOST_HTTP_PROTO_DECL
     void
     set_version(
         http_proto::version v);
@@ -221,7 +220,7 @@ class response_base
     }
 
 private:
-    BOOST_HTTP_PROTO_DECL
+    
     void
     set_start_line_impl(
         http_proto::status sc,
diff --git a/include/boost/http_proto/serializer.hpp b/include/boost/http_proto/serializer.hpp
index e0e65d08..3ae6d12a 100644
--- a/include/boost/http_proto/serializer.hpp
+++ b/include/boost/http_proto/serializer.hpp
@@ -53,7 +53,7 @@ class message_base;
     called, or the serializer is destroyed, otherwise the
     behavior is undefined.
 */
-class serializer
+class BOOST_HTTP_PROTO_DECL serializer
 {
 public:
     class stream;
@@ -68,8 +68,7 @@ class serializer
 
     /** Destructor
     */
-    BOOST_HTTP_PROTO_DECL
-    ~serializer();
+        ~serializer();
 
     /** Constructor
         Default-constructed serializers do not reference any implementation;
@@ -100,8 +99,7 @@ class serializer
 
         @param other The serializer to move from.
     */
-    BOOST_HTTP_PROTO_DECL
-    serializer(
+        serializer(
         serializer&& other) noexcept;
 
     /** Assignment.
@@ -119,7 +117,7 @@ class serializer
         @param other The serializer to move from.
         @return A reference to this object.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     serializer&
     operator=(serializer&& other) noexcept;
 
@@ -168,7 +166,7 @@ class serializer
             @ref install_serializer_service,
             @ref config.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     explicit
     serializer(
         capy::polystore& ctx);
@@ -179,7 +177,7 @@ class serializer
         prepares the serializer to start
         serialization of a new message.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     reset() noexcept;
 
@@ -217,7 +215,7 @@ class serializer
             @ref message_base.
     */
     void
-    BOOST_HTTP_PROTO_DECL
+    
     start(message_base const& m);
 
     /** Start serializing a message with a buffer sequence body
@@ -424,7 +422,7 @@ class serializer
             @ref stream,
             @ref message_base.
      */
-    BOOST_HTTP_PROTO_DECL
+    
     stream
     start_stream(
         message_base const& m);
@@ -484,7 +482,7 @@ class serializer
             @ref is_done,
             @ref const_buffers_type.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     auto
     prepare() ->
         system::result<
@@ -524,13 +522,12 @@ class serializer
             @ref is_done,
             @ref const_buffers_type.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     consume(std::size_t n);
 
     /** Return true if serialization is complete.
     */
-    BOOST_HTTP_PROTO_DECL
     bool
     is_done() const noexcept;
 
@@ -540,22 +537,22 @@ class serializer
     template<class>
     class cbs_gen_impl;
 
-    BOOST_HTTP_PROTO_DECL
+    
     detail::workspace&
     ws();
 
-    BOOST_HTTP_PROTO_DECL
+    
     void
     start_init(
         message_base const&);
 
-    BOOST_HTTP_PROTO_DECL
+    
     void
     start_buffers(
         message_base const&,
         cbs_gen&);
 
-    BOOST_HTTP_PROTO_DECL
+    
     void
     start_source(
         message_base const&,
@@ -665,6 +662,7 @@ struct serializer::config
         @ref serializer::config,
         @ref serializer.
 */
+
 BOOST_HTTP_PROTO_DECL
 void
 install_serializer_service(
@@ -694,7 +692,7 @@ install_serializer_service(
     @see
         @ref serializer::start_stream
 */
-class serializer::stream
+class BOOST_HTTP_PROTO_DECL serializer::stream
 {
 public:
     /** The type used to represent a sequence
@@ -774,7 +772,7 @@ class serializer::stream
         @throw std::logic_error
         `this->is_open() == false`.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     std::size_t
     capacity() const;
 
@@ -805,8 +803,7 @@ class serializer::stream
             @ref commit,
             @ref capacity.
     */
-    BOOST_HTTP_PROTO_DECL
-    mutable_buffers_type
+        mutable_buffers_type
     prepare();
 
     /** Commit data to the serializer.
@@ -837,7 +834,7 @@ class serializer::stream
             @ref prepare,
             @ref capacity.
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     commit(std::size_t n);
 
@@ -855,7 +852,7 @@ class serializer::stream
         this->is_open() == false
         @endcode
     */
-    BOOST_HTTP_PROTO_DECL
+    
     void
     close() noexcept;
 
diff --git a/include/boost/http_proto/server/route_handler.hpp b/include/boost/http_proto/server/route_handler.hpp
index 399310d5..3c4bee05 100644
--- a/include/boost/http_proto/server/route_handler.hpp
+++ b/include/boost/http_proto/server/route_handler.hpp
@@ -30,11 +30,12 @@ struct acceptor_config
     bool is_admin;
 };
 
-//-----------------------------------------------
+BOOST_HTTP_PROTO_MSVC_WARNING_PUSH
+BOOST_HTTP_PROTO_MSVC_DISABLE_4251_4275
 
 /** Parameters object for HTTP route handlers
 */
-struct BOOST_SYMBOL_VISIBLE
+struct BOOST_HTTP_PROTO_DECL
     route_params : route_params_base
 {
     /** The complete request target
@@ -82,7 +83,6 @@ struct BOOST_SYMBOL_VISIBLE
 
     /** Destructor
     */
-    BOOST_HTTP_PROTO_DECL
     ~route_params();
 
     /** Reset the object for a new request.
@@ -90,7 +90,6 @@ struct BOOST_SYMBOL_VISIBLE
         the previous request, preparing the object
         for use with a new request.
     */
-    BOOST_HTTP_PROTO_DECL
     void reset();
 
     /** Set the status code of the response.
@@ -101,11 +100,9 @@ struct BOOST_SYMBOL_VISIBLE
         @param code The status code to set.
         @return A reference to this response.
     */
-    BOOST_HTTP_PROTO_DECL
     route_params&
     status(http_proto::status code);
 
-    BOOST_HTTP_PROTO_DECL
     route_params&
     set_body(std::string s);
 
@@ -147,9 +144,9 @@ struct BOOST_SYMBOL_VISIBLE
 protected:
     /** A task to be invoked later
     */
-    struct task
+    struct BOOST_HTTP_PROTO_DECL task
     {
-        virtual ~task() = default;
+        virtual ~task();
 
         /** Invoke the task.
 
@@ -163,7 +160,6 @@ struct BOOST_SYMBOL_VISIBLE
         Subclasses must schedule task_ to be invoked at an unspecified
         point in the future.
     */
-    BOOST_HTTP_PROTO_DECL
     virtual void do_post();
 
     std::unique_ptr<task> task_;
diff --git a/include/boost/http_proto/server/router_types.hpp b/include/boost/http_proto/server/router_types.hpp
index 39f2306f..eef0b25c 100644
--- a/include/boost/http_proto/server/router_types.hpp
+++ b/include/boost/http_proto/server/router_types.hpp
@@ -17,6 +17,7 @@
 #include <boost/system/error_code.hpp>
 #include <exception>
 #include <string>
+#include <boost/http_proto/detail/config.hpp>
 #include <type_traits>
 
 namespace boost {
@@ -157,7 +158,7 @@ class resumer;
     This holds an reference to an implementation
     which detaches the handler from its session.
 */
-class detacher
+class BOOST_HTTP_PROTO_DECL detacher
 {
 public:
     /** Base class of the implementation
@@ -291,12 +292,15 @@ class any_router;
 template<class>
 class basic_router;
 
+BOOST_HTTP_PROTO_MSVC_WARNING_PUSH
+BOOST_HTTP_PROTO_MSVC_DISABLE_4251_4275
+
 /** Base class for request objects
 
     This is a required public base for any `Request`
     type used with @ref basic_router.
 */
-class route_params_base
+class BOOST_HTTP_PROTO_DECL route_params_base
 {
 public:
     /** The mount path of the current router
@@ -333,6 +337,9 @@ class route_params_base
     bool strict = false;
 };
 
+
+BOOST_HTTP_PROTO_MSVC_WARNING_POP
+
 } // http_proto
 } // boost
 
diff --git a/src/fields_base.cpp b/src/fields_base.cpp
index ba62e591..6e069b29 100644
--- a/src/fields_base.cpp
+++ b/src/fields_base.cpp
@@ -850,6 +850,7 @@ find_all(
         &h_, find(name).i_);
 }
 
+BOOST_HTTP_PROTO_DECL
 std::ostream&
 operator<<(
     std::ostream& os,
diff --git a/src/server/route_handler.cpp b/src/server/route_handler.cpp
index 5aad08e1..9036d967 100644
--- a/src/server/route_handler.cpp
+++ b/src/server/route_handler.cpp
@@ -20,6 +20,9 @@ route_params::
 {
 }
 
+route_params::task::
+~task() = default;
+
 route_params&
 route_params::
 status(