diff --git a/hpb/BUILD b/hpb/BUILD
index 1f007ed4fe..67b10e1285 100644
--- a/hpb/BUILD
+++ b/hpb/BUILD
@@ -55,6 +55,7 @@ cc_library(
     deps = [
         ":extension_lock",
         "//hpb:ptr",
+        "//hpb/internal",
         "//hpb/internal:template_help",
         "//upb:base",
         "//upb:mem",
diff --git a/hpb/hpb.h b/hpb/hpb.h
index 097fdc81e2..dcb27da1e9 100644
--- a/hpb/hpb.h
+++ b/hpb/hpb.h
@@ -15,6 +15,7 @@
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"
+#include "google/protobuf/hpb/internal/internal.h"
 #include "google/protobuf/hpb/internal/template_help.h"
 #include "google/protobuf/hpb/ptr.h"
 #include "upb/base/status.hpp"
@@ -69,45 +70,6 @@ absl::Status MessageEncodeError(upb_EncodeStatus status,
                                 SourceLocation loc = SourceLocation::current());
 
 namespace internal {
-struct PrivateAccess {
-  template <typename T>
-  static auto* GetInternalMsg(T&& message) {
-    return message->msg();
-  }
-  template <typename T>
-  static auto Proxy(upb_Message* p, upb_Arena* arena) {
-    return typename T::Proxy(p, arena);
-  }
-  template <typename T>
-  static auto CProxy(const upb_Message* p, upb_Arena* arena) {
-    return typename T::CProxy(p, arena);
-  }
-  template <typename T>
-  static auto CreateMessage(upb_Arena* arena) {
-    return typename T::Proxy(upb_Message_New(T::minitable(), arena), arena);
-  }
-
-  template <typename ExtensionId>
-  static constexpr uint32_t GetExtensionNumber(const ExtensionId& id) {
-    return id.number();
-  }
-};
-
-template <typename T>
-auto* GetInternalMsg(T&& message) {
-  return PrivateAccess::GetInternalMsg(std::forward<T>(message));
-}
-
-template <typename T>
-typename T::Proxy CreateMessageProxy(upb_Message* msg, upb_Arena* arena) {
-  return typename T::Proxy(msg, arena);
-}
-
-template <typename T>
-typename T::CProxy CreateMessage(const upb_Message* msg, upb_Arena* arena) {
-  return PrivateAccess::CProxy<T>(msg, arena);
-}
-
 class ExtensionMiniTableProvider {
  public:
   constexpr explicit ExtensionMiniTableProvider(
diff --git a/hpb/internal/BUILD b/hpb/internal/BUILD
index 35268e3000..5fd24ba64a 100644
--- a/hpb/internal/BUILD
+++ b/hpb/internal/BUILD
@@ -18,3 +18,14 @@ cc_library(
         "//hpb:ptr",
     ],
 )
+
+cc_library(
+    name = "internal",
+    hdrs = ["internal.h"],
+    compatible_with = ["//buildenv/target:non_prod"],
+    visibility = ["//hpb:__subpackages__"],
+    deps = [
+        "//upb:mem",
+        "//upb:message",
+    ],
+)
diff --git a/hpb/internal/internal.h b/hpb/internal/internal.h
new file mode 100644
index 0000000000..bc00cafbdd
--- /dev/null
+++ b/hpb/internal/internal.h
@@ -0,0 +1,53 @@
+#ifndef GOOGLE_PROTOBUF_HPB_INTERNAL_INTERNAL_H__
+#define GOOGLE_PROTOBUF_HPB_INTERNAL_INTERNAL_H__
+
+#include <cstdint>
+#include <utility>
+
+#include "upb/mem/arena.h"
+#include "upb/message/message.h"
+
+namespace hpb::internal {
+
+struct PrivateAccess {
+  template <typename T>
+  static auto* GetInternalMsg(T&& message) {
+    return message->msg();
+  }
+  template <typename T>
+  static auto Proxy(upb_Message* p, upb_Arena* arena) {
+    return typename T::Proxy(p, arena);
+  }
+  template <typename T>
+  static auto CProxy(const upb_Message* p, upb_Arena* arena) {
+    return typename T::CProxy(p, arena);
+  }
+  template <typename T>
+  static auto CreateMessage(upb_Arena* arena) {
+    return typename T::Proxy(upb_Message_New(T::minitable(), arena), arena);
+  }
+
+  template <typename ExtensionId>
+  static constexpr uint32_t GetExtensionNumber(const ExtensionId& id) {
+    return id.number();
+  }
+};
+
+template <typename T>
+auto* GetInternalMsg(T&& message) {
+  return PrivateAccess::GetInternalMsg(std::forward<T>(message));
+}
+
+template <typename T>
+typename T::Proxy CreateMessageProxy(upb_Message* msg, upb_Arena* arena) {
+  return typename T::Proxy(msg, arena);
+}
+
+template <typename T>
+typename T::CProxy CreateMessage(const upb_Message* msg, upb_Arena* arena) {
+  return PrivateAccess::CProxy<T>(msg, arena);
+}
+
+}  // namespace hpb::internal
+
+#endif  // GOOGLE_PROTOBUF_HPB_INTERNAL_INTERNAL_H__