diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 89c43aa8..1425b1e9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -150,8 +150,18 @@ jobs:
       run: |
         autoreconf -i
         ./configure
-    - name: Configure cmake
-      if: matrix.buildtool == 'cmake'
+    - name: Configure cmake (Linux)
+      if: matrix.buildtool == 'cmake' && runner.os == 'Linux'
+      run: |
+        make dist
+        VERSION=$(grep PACKAGE_VERSION config.h | cut -d' ' -f3 | tr -d '"')
+        tar xf nghttp2-$VERSION.tar.gz
+        cd nghttp2-$VERSION
+        echo 'NGHTTP2_CMAKE_DIR='"$PWD" >> $GITHUB_ENV
+
+        cmake -DENABLE_WERROR=1 -DWITH_MRUBY=1 -DWITH_NEVERBLEED=1 -DENABLE_APP=1 $EXTRA_CMAKE_OPTS -DCPPFLAGS="$CPPFLAGS" -DLDFLAGS="$LDFLAGS" .
+    - name: Configure cmake (MacOS)
+      if: matrix.buildtool == 'cmake' && runner.os == 'macOS'
       run: |
         make dist
         VERSION=$(grep PACKAGE_VERSION config.h | cut -d' ' -f3 | tr -d '"')
@@ -162,12 +172,17 @@ jobs:
         # This fixes infamous 'stdio.h not found' error.
         echo 'SDKROOT='"$(xcrun --sdk macosx --show-sdk-path)" >> $GITHUB_ENV
 
-        cmake -DENABLE_WERROR=1 -DWITH_MRUBY=1 -DWITH_NEVERBLEED=1 -DENABLE_APP=1 $EXTRA_CMAKE_OPTS -DCPPFLAGS="$CPPFLAGS" -DLDFLAGS="$LDFLAGS" .
-    - name: Build nghttp2 with autotools
-      if: matrix.buildtool == 'autotools'
+        cmake -DENABLE_WERROR=1 -DWITH_MRUBY=1 -DENABLE_APP=1 $EXTRA_CMAKE_OPTS -DCPPFLAGS="$CPPFLAGS" -DLDFLAGS="$LDFLAGS" .
+    - name: Build nghttp2 with autotools (Linux)
+      if: matrix.buildtool == 'autotools' && runner.os == 'Linux'
       run: |
-        make -j"$(nproc 2> /dev/null || sysctl -n hw.ncpu)" distcheck \
+        make -j"$(nproc)" distcheck \
           DISTCHECK_CONFIGURE_FLAGS="--with-mruby --with-neverbleed --with-libev --enable-werror $EXTRA_AUTOTOOLS_OPTS CPPFLAGS=\"$CPPFLAGS\" LDFLAGS=\"$LDFLAGS\""
+    - name: Build nghttp2 with autotools (MacOS)
+      if: matrix.buildtool == 'autotools' && runner.os == 'macOS'
+      run: |
+        make -j"$(sysctl -n hw.ncpu)" distcheck \
+          DISTCHECK_CONFIGURE_FLAGS="--with-mruby --with-libev --enable-werror $EXTRA_AUTOTOOLS_OPTS CPPFLAGS=\"$CPPFLAGS\" LDFLAGS=\"$LDFLAGS\""
     - name: Build nghttp2 with cmake
       if: matrix.buildtool == 'cmake'
       run: |
diff --git a/src/shrpx_connection.cc b/src/shrpx_connection.cc
index e8f5192e..a0fcab76 100644
--- a/src/shrpx_connection.cc
+++ b/src/shrpx_connection.cc
@@ -44,13 +44,13 @@ using namespace nghttp2;
 
 namespace shrpx {
 
-#if !LIBRESSL_2_7_API && !OPENSSL_1_1_API
+#if !LIBRESSL_3_5_API && !LIBRESSL_2_7_API && !OPENSSL_1_1_API
 
 void *BIO_get_data(BIO *bio) { return bio->ptr; }
 void BIO_set_data(BIO *bio, void *ptr) { bio->ptr = ptr; }
 void BIO_set_init(BIO *bio, int init) { bio->init = init; }
 
-#endif // !LIBRESSL_2_7_API && !OPENSSL_1_1_API
+#endif // !LIBRESSL_3_5_API && !LIBRESSL_2_7_API && !OPENSSL_1_1_API
 
 Connection::Connection(struct ev_loop *loop, int fd, SSL *ssl,
                        MemchunkPool *mcpool, ev_tstamp write_timeout,
@@ -259,14 +259,14 @@ long shrpx_bio_ctrl(BIO *b, int cmd, long num, void *ptr) {
 
 namespace {
 int shrpx_bio_create(BIO *b) {
-#if OPENSSL_1_1_API
+#if OPENSSL_1_1_API || LIBRESSL_3_5_API
   BIO_set_init(b, 1);
-#else  // !OPENSSL_1_1_API
+#else  // !OPENSSL_1_1_API && !LIBRESSL_3_5_API
   b->init = 1;
   b->num = 0;
   b->ptr = nullptr;
   b->flags = 0;
-#endif // !OPENSSL_1_1_API
+#endif // !OPENSSL_1_1_API && !LIBRESSL_3_5_API
   return 1;
 }
 } // namespace
@@ -277,17 +277,17 @@ int shrpx_bio_destroy(BIO *b) {
     return 0;
   }
 
-#if !OPENSSL_1_1_API
+#if !OPENSSL_1_1_API && !LIBRESSL_3_5_API
   b->ptr = nullptr;
   b->init = 0;
   b->flags = 0;
-#endif // !OPENSSL_1_1_API
+#endif // !OPENSSL_1_1_API && !LIBRESSL_3_5_API
 
   return 1;
 }
 } // namespace
 
-#if OPENSSL_1_1_API
+#if OPENSSL_1_1_API || LIBRESSL_3_5_API
 
 BIO_METHOD *create_bio_method() {
   auto meth = BIO_meth_new(BIO_TYPE_FD, "nghttpx-bio");
@@ -302,7 +302,7 @@ BIO_METHOD *create_bio_method() {
   return meth;
 }
 
-#else // !OPENSSL_1_1_API
+#else // !OPENSSL_1_1_API && !LIBRESSL_3_5_API
 
 BIO_METHOD *create_bio_method() {
   static auto meth = new BIO_METHOD{
@@ -314,7 +314,7 @@ BIO_METHOD *create_bio_method() {
   return meth;
 }
 
-#endif // !OPENSSL_1_1_API
+#endif // !OPENSSL_1_1_API && !LIBRESSL_3_5_API
 
 void Connection::set_ssl(SSL *ssl) {
   tls.ssl = ssl;
diff --git a/src/ssl_compat.h b/src/ssl_compat.h
index 87f326a4..79f9edbf 100644
--- a/src/ssl_compat.h
+++ b/src/ssl_compat.h
@@ -33,6 +33,7 @@
 #    define LIBRESSL_IN_USE 1
 #    define LIBRESSL_LEGACY_API (LIBRESSL_VERSION_NUMBER < 0x20700000L)
 #    define LIBRESSL_2_7_API (LIBRESSL_VERSION_NUMBER >= 0x20700000L)
+#    define LIBRESSL_3_5_API (LIBRESSL_VERSION_NUMBER >= 0x30500000L)
 #  else // !LIBRESSL_VERSION_NUMBER
 #    define OPENSSL_1_1_API (OPENSSL_VERSION_NUMBER >= 0x1010000fL)
 #    define OPENSSL_1_1_1_API (OPENSSL_VERSION_NUMBER >= 0x10101000L)
@@ -40,6 +41,7 @@
 #    define LIBRESSL_IN_USE 0
 #    define LIBRESSL_LEGACY_API 0
 #    define LIBRESSL_2_7_API 0
+#    define LIBRESSL_3_5_API 0
 #  endif // !LIBRESSL_VERSION_NUMBER
 
 #endif // OPENSSL_COMPAT_H