diff --git a/lib/yunq/message_view.h b/lib/yunq/message_view.h
index 85c5fb6..996ba8f 100644
--- a/lib/yunq/message_view.h
+++ b/lib/yunq/message_view.h
@@ -6,23 +6,10 @@
 #include <glacier/status/error_or.h>
 #include <glacier/status/status.h>
 
+#include "yunq/yunq.h"
+
 namespace yunq {
 
-const uint64_t kHeaderSize = 24;  // 4x uint32, 1x uint64
-
-struct MessageHeader {
-  uint32_t ident;
-  uint32_t core_length;
-  uint32_t length;
-  uint32_t crc32;
-  uint64_t options;
-} __attribute__((packed));
-
-struct ExtensionPointer {
-  uint32_t offset;
-  uint32_t length;
-};
-
 class MessageView {
  public:
   MessageView(const glcr::ByteBuffer& buffer, uint64_t offset)
diff --git a/lib/yunq/serialize.cpp b/lib/yunq/serialize.cpp
index 749063b..6522ab3 100644
--- a/lib/yunq/serialize.cpp
+++ b/lib/yunq/serialize.cpp
@@ -7,12 +7,38 @@ const uint64_t kIdentByte = 0x33441122;
 
 }  // namespace
 
-void WriteHeader(glcr::ByteBuffer& bytes, uint64_t offset, uint32_t core_size,
-                 uint32_t extension_size) {
-  bytes.WriteAt<uint32_t>(offset + 0, kIdentByte);
-  bytes.WriteAt<uint32_t>(offset + 4, core_size);
-  bytes.WriteAt<uint32_t>(offset + 8, extension_size);
-  bytes.WriteAt<uint32_t>(offset + 12, 0);  // TODO: Calculate CRC32.
+void Serializer::WriteHeader() {
+  buffer_.WriteAt<uint32_t>(offset_ + 0, kIdentByte);
+  buffer_.WriteAt<uint32_t>(offset_ + 4, core_size_);
+  buffer_.WriteAt<uint32_t>(offset_ + 8, next_extension_);
+  buffer_.WriteAt<uint32_t>(offset_ + 12, 0);  // TODO: Calculate CRC32.
 }
 
+template <>
+void Serializer::WriteField<glcr::String>(uint64_t field_index,
+                                          const glcr::String& value) {
+  ExtensionPointer ptr{
+      .offset = (uint32_t)next_extension_,
+      // FIXME: Check downcast of str length.
+      .length = (uint32_t)value.length(),
+  };
+
+  buffer_.WriteStringAt(offset_ + next_extension_, value);
+  next_extension_ += ptr.length;
+
+  buffer_.WriteAt<ExtensionPointer>(field_offset(field_index), ptr);
+}
+
+void Serializer::WriteCapability(uint64_t field_index, uint64_t value) {
+  if (caps_) {
+    buffer_.WriteAt<uint64_t>(field_offset(field_index), next_cap_);
+    caps_.value().get().WriteAt(next_cap_++, value);
+  } else {
+    WriteField<uint64_t>(field_index, value);
+  }
+}
+
+void Serializer::WriteRepeatedCapability(uint64_t field_index,
+                                         const glcr::Vector<uint64_t>& value) {}
+
 }  // namespace yunq
diff --git a/lib/yunq/serialize.h b/lib/yunq/serialize.h
index cdb76c1..ae6a77b 100644
--- a/lib/yunq/serialize.h
+++ b/lib/yunq/serialize.h
@@ -1,11 +1,84 @@
 #pragma once
 
 #include <glacier/buffer/byte_buffer.h>
+#include <glacier/buffer/cap_buffer.h>
+#include <glacier/container/optional.h>
+#include <glacier/container/vector.h>
+#include <glacier/memory/reference.h>
 #include <glacier/status/status.h>
 
+#include "yunq/yunq.h"
+
 namespace yunq {
 
-void WriteHeader(glcr::ByteBuffer& bytes, uint64_t offset, uint32_t core_size,
-                 uint32_t extension_size);
+class Serializer {
+ public:
+  Serializer(glcr::ByteBuffer& bytes, uint64_t offset, uint64_t num_fields)
+      : buffer_(bytes),
+        offset_(offset),
+        next_extension_(kHeaderSize + (8 * num_fields)),
+        core_size_(next_extension_),
+        caps_() {}
+  Serializer(glcr::ByteBuffer& bytes, uint64_t offset, uint64_t num_fields,
+             glcr::CapBuffer& caps)
+      : buffer_(bytes),
+        offset_(offset),
+        next_extension_(kHeaderSize + (8 * num_fields)),
+        core_size_(next_extension_),
+        caps_(caps) {}
+
+  template <typename T>
+  void WriteField(uint64_t field_index, const T& value);
+
+  template <typename T>
+  void WriteRepeated(uint64_t field_index, const glcr::Vector<T>& value);
+
+  void WriteCapability(uint64_t field_index, uint64_t value);
+
+  void WriteRepeatedCapability(uint64_t field_index,
+                               const glcr::Vector<uint64_t>& value);
+
+  void WriteHeader();
+
+  uint64_t size() const { return next_extension_; }
+
+ private:
+  glcr::ByteBuffer& buffer_;
+  uint64_t offset_;
+  uint64_t next_extension_;
+  uint64_t core_size_;
+  uint64_t next_cap_ = 0;
+  glcr::Optional<glcr::Ref<glcr::CapBuffer>> caps_;
+
+  uint64_t field_offset(uint64_t field_index) const {
+    return offset_ + kHeaderSize + (8 * field_index);
+  }
+};
+
+template <typename T>
+void Serializer::WriteField(uint64_t field_index, const T& value) {
+  buffer_.WriteAt<T>(field_offset(field_index), value);
+}
+
+template <>
+void Serializer::WriteField<glcr::String>(uint64_t field_index,
+                                          const glcr::String& value);
+
+template <typename T>
+void Serializer::WriteRepeated(uint64_t field_index,
+                               const glcr::Vector<T>& value) {
+  ExtensionPointer ptr{
+      .offset = (uint32_t)next_extension_,
+      .length = (uint32_t)(value.size() * sizeof(T)),
+  };
+
+  next_extension_ += ptr.length;
+  buffer_.WriteAt<ExtensionPointer>(field_offset(field_index), ptr);
+
+  for (uint64_t i = 0; i < value.size(); i++) {
+    uint32_t ext_offset = offset_ + ptr.offset + (i * sizeof(T));
+    buffer_.WriteAt<T>(ext_offset, value.at(i));
+  }
+}
 
 }  // namespace yunq
diff --git a/lib/yunq/yunq.h b/lib/yunq/yunq.h
new file mode 100644
index 0000000..3a33a8c
--- /dev/null
+++ b/lib/yunq/yunq.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <stdint.h>
+
+namespace yunq {
+
+struct MessageHeader {
+  uint32_t ident;
+  uint32_t core_length;
+  uint32_t length;
+  uint32_t crc32;
+  uint64_t options;
+} __attribute__((packed));
+
+const uint64_t kHeaderSize = 24;  // 4x uint32, 1x uint64
+
+struct ExtensionPointer {
+  uint32_t offset;
+  uint32_t length;
+};
+
+}  // namespace yunq
diff --git a/sys/denali/lib/denali/denali.yunq.cpp b/sys/denali/lib/denali/denali.yunq.cpp
index ffdc39a..329db3d 100644
--- a/sys/denali/lib/denali/denali.yunq.cpp
+++ b/sys/denali/lib/denali/denali.yunq.cpp
@@ -38,36 +38,31 @@ glcr::Status ReadRequest::ParseFromBytesInternal(const yunq::MessageView& messag
 }
 
 uint64_t ReadRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 3);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), device_id());
+  serializer.WriteField<uint64_t>(0, device_id_);
   // Write lba.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), lba());
+  serializer.WriteField<uint64_t>(1, lba_);
   // Write size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), size());
+  serializer.WriteField<uint64_t>(2, size_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t ReadRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 3, caps);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), device_id());
+  serializer.WriteField<uint64_t>(0, device_id_);
   // Write lba.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), lba());
+  serializer.WriteField<uint64_t>(1, lba_);
   // Write size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), size());
+  serializer.WriteField<uint64_t>(2, size_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status ReadManyRequest::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -94,80 +89,31 @@ glcr::Status ReadManyRequest::ParseFromBytesInternal(const yunq::MessageView& me
 }
 
 uint64_t ReadManyRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 3);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), device_id());
+  serializer.WriteField<uint64_t>(0, device_id_);
   // Write lba.
-  ExtPointer lba_ptr{
-    .offset = next_extension,
-    .length = (uint32_t)(lba().size() * sizeof(uint64_t)),
-  };
-
-  next_extension += lba_ptr.length;
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 1), lba_ptr);
-
-  for (uint64_t i = 0; i < lba().size(); i++) {
-    uint32_t ext_offset = offset + lba_ptr.offset + (i * sizeof(uint64_t));
-    bytes.WriteAt<uint64_t>(ext_offset, lba().at(i));
-  }
+  serializer.WriteRepeated<uint64_t>(1, lba_);
   // Write sector_cnt.
-  ExtPointer sector_cnt_ptr{
-    .offset = next_extension,
-    .length = (uint32_t)(sector_cnt().size() * sizeof(uint64_t)),
-  };
+  serializer.WriteRepeated<uint64_t>(2, sector_cnt_);
 
-  next_extension += sector_cnt_ptr.length;
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 2), sector_cnt_ptr);
+  serializer.WriteHeader();
 
-  for (uint64_t i = 0; i < sector_cnt().size(); i++) {
-    uint32_t ext_offset = offset + sector_cnt_ptr.offset + (i * sizeof(uint64_t));
-    bytes.WriteAt<uint64_t>(ext_offset, sector_cnt().at(i));
-  }
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t ReadManyRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 3, caps);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), device_id());
+  serializer.WriteField<uint64_t>(0, device_id_);
   // Write lba.
-  ExtPointer lba_ptr{
-    .offset = next_extension,
-    .length = (uint32_t)(lba().size() * sizeof(uint64_t)),
-  };
-
-  next_extension += lba_ptr.length;
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 1), lba_ptr);
-
-  for (uint64_t i = 0; i < lba().size(); i++) {
-    uint32_t ext_offset = offset + lba_ptr.offset + (i * sizeof(uint64_t));
-    bytes.WriteAt<uint64_t>(ext_offset, lba().at(i));
-  }
+  serializer.WriteRepeated<uint64_t>(1, lba_);
   // Write sector_cnt.
-  ExtPointer sector_cnt_ptr{
-    .offset = next_extension,
-    .length = (uint32_t)(sector_cnt().size() * sizeof(uint64_t)),
-  };
+  serializer.WriteRepeated<uint64_t>(2, sector_cnt_);
 
-  next_extension += sector_cnt_ptr.length;
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 2), sector_cnt_ptr);
+  serializer.WriteHeader();
 
-  for (uint64_t i = 0; i < sector_cnt().size(); i++) {
-    uint32_t ext_offset = offset + sector_cnt_ptr.offset + (i * sizeof(uint64_t));
-    bytes.WriteAt<uint64_t>(ext_offset, sector_cnt().at(i));
-  }
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status ReadResponse::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -195,37 +141,30 @@ glcr::Status ReadResponse::ParseFromBytesInternal(const yunq::MessageView& messa
 }
 
 uint64_t ReadResponse::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 3);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), device_id());
+  serializer.WriteField<uint64_t>(0, device_id_);
   // Write size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), size());
+  serializer.WriteField<uint64_t>(1, size_);
   // Write memory.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), 0);
+  serializer.WriteCapability(2, memory_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t ReadResponse::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 3, caps);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), device_id());
+  serializer.WriteField<uint64_t>(0, device_id_);
   // Write size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), size());
+  serializer.WriteField<uint64_t>(1, size_);
   // Write memory.
-  caps.WriteAt(next_cap, memory());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), next_cap++);
+  serializer.WriteCapability(2, memory_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
diff --git a/sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.cpp b/sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.cpp
index 0c0d70b..a529810 100644
--- a/sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.cpp
+++ b/sys/victoriafalls/lib/victoriafalls/victoriafalls.yunq.cpp
@@ -34,46 +34,23 @@ glcr::Status OpenFileRequest::ParseFromBytesInternal(const yunq::MessageView& me
 }
 
 uint64_t OpenFileRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 1);
   // Write path.
-  ExtPointer path_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)path().length(),
-  };
+  serializer.WriteField<glcr::String>(0, path_);
 
-  bytes.WriteStringAt(offset + next_extension, path());
-  next_extension += path_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), path_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t OpenFileRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 1, caps);
   // Write path.
-  ExtPointer path_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)path().length(),
-  };
+  serializer.WriteField<glcr::String>(0, path_);
 
-  bytes.WriteStringAt(offset + next_extension, path());
-  next_extension += path_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), path_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status OpenFileResponse::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -101,56 +78,31 @@ glcr::Status OpenFileResponse::ParseFromBytesInternal(const yunq::MessageView& m
 }
 
 uint64_t OpenFileResponse::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 3);
   // Write path.
-  ExtPointer path_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)path().length(),
-  };
-
-  bytes.WriteStringAt(offset + next_extension, path());
-  next_extension += path_ptr.length;
-
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), path_ptr);
+  serializer.WriteField<glcr::String>(0, path_);
   // Write size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), size());
+  serializer.WriteField<uint64_t>(1, size_);
   // Write memory.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), 0);
+  serializer.WriteCapability(2, memory_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t OpenFileResponse::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 3, caps);
   // Write path.
-  ExtPointer path_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)path().length(),
-  };
-
-  bytes.WriteStringAt(offset + next_extension, path());
-  next_extension += path_ptr.length;
-
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), path_ptr);
+  serializer.WriteField<glcr::String>(0, path_);
   // Write size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), size());
+  serializer.WriteField<uint64_t>(1, size_);
   // Write memory.
-  caps.WriteAt(next_cap, memory());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), next_cap++);
+  serializer.WriteCapability(2, memory_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status GetDirectoryRequest::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -171,46 +123,23 @@ glcr::Status GetDirectoryRequest::ParseFromBytesInternal(const yunq::MessageView
 }
 
 uint64_t GetDirectoryRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 1);
   // Write path.
-  ExtPointer path_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)path().length(),
-  };
+  serializer.WriteField<glcr::String>(0, path_);
 
-  bytes.WriteStringAt(offset + next_extension, path());
-  next_extension += path_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), path_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t GetDirectoryRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 1, caps);
   // Write path.
-  ExtPointer path_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)path().length(),
-  };
+  serializer.WriteField<glcr::String>(0, path_);
 
-  bytes.WriteStringAt(offset + next_extension, path());
-  next_extension += path_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), path_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status Directory::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -231,45 +160,22 @@ glcr::Status Directory::ParseFromBytesInternal(const yunq::MessageView& message)
 }
 
 uint64_t Directory::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 1);
   // Write filenames.
-  ExtPointer filenames_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)filenames().length(),
-  };
+  serializer.WriteField<glcr::String>(0, filenames_);
 
-  bytes.WriteStringAt(offset + next_extension, filenames());
-  next_extension += filenames_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), filenames_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t Directory::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 1, caps);
   // Write filenames.
-  ExtPointer filenames_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)filenames().length(),
-  };
+  serializer.WriteField<glcr::String>(0, filenames_);
 
-  bytes.WriteStringAt(offset + next_extension, filenames());
-  next_extension += filenames_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), filenames_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 
diff --git a/sys/voyageurs/lib/voyageurs/voyageurs.yunq.cpp b/sys/voyageurs/lib/voyageurs/voyageurs.yunq.cpp
index 863a0d9..9a69f66 100644
--- a/sys/voyageurs/lib/voyageurs/voyageurs.yunq.cpp
+++ b/sys/voyageurs/lib/voyageurs/voyageurs.yunq.cpp
@@ -37,29 +37,22 @@ glcr::Status KeyboardListener::ParseFromBytesInternal(const yunq::MessageView& m
 }
 
 uint64_t KeyboardListener::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 1);
   // Write port_capability.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), 0);
+  serializer.WriteCapability(0, port_capability_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t KeyboardListener::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 1, caps);
   // Write port_capability.
-  caps.WriteAt(next_cap, port_capability());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), next_cap++);
+  serializer.WriteCapability(0, port_capability_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
diff --git a/sys/yellowstone/lib/yellowstone/yellowstone.yunq.cpp b/sys/yellowstone/lib/yellowstone/yellowstone.yunq.cpp
index 0b21546..33a5f0d 100644
--- a/sys/yellowstone/lib/yellowstone/yellowstone.yunq.cpp
+++ b/sys/yellowstone/lib/yellowstone/yellowstone.yunq.cpp
@@ -41,52 +41,27 @@ glcr::Status RegisterEndpointRequest::ParseFromBytesInternal(const yunq::Message
 }
 
 uint64_t RegisterEndpointRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 2;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 2);
   // Write endpoint_name.
-  ExtPointer endpoint_name_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)endpoint_name().length(),
-  };
-
-  bytes.WriteStringAt(offset + next_extension, endpoint_name());
-  next_extension += endpoint_name_ptr.length;
-
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), endpoint_name_ptr);
+  serializer.WriteField<glcr::String>(0, endpoint_name_);
   // Write endpoint_capability.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), 0);
+  serializer.WriteCapability(1, endpoint_capability_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t RegisterEndpointRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 2;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 2, caps);
   // Write endpoint_name.
-  ExtPointer endpoint_name_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)endpoint_name().length(),
-  };
-
-  bytes.WriteStringAt(offset + next_extension, endpoint_name());
-  next_extension += endpoint_name_ptr.length;
-
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), endpoint_name_ptr);
+  serializer.WriteField<glcr::String>(0, endpoint_name_);
   // Write endpoint_capability.
-  caps.WriteAt(next_cap, endpoint_capability());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), next_cap++);
+  serializer.WriteCapability(1, endpoint_capability_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status GetEndpointRequest::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -107,46 +82,23 @@ glcr::Status GetEndpointRequest::ParseFromBytesInternal(const yunq::MessageView&
 }
 
 uint64_t GetEndpointRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 1);
   // Write endpoint_name.
-  ExtPointer endpoint_name_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)endpoint_name().length(),
-  };
+  serializer.WriteField<glcr::String>(0, endpoint_name_);
 
-  bytes.WriteStringAt(offset + next_extension, endpoint_name());
-  next_extension += endpoint_name_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), endpoint_name_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t GetEndpointRequest::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 1, caps);
   // Write endpoint_name.
-  ExtPointer endpoint_name_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t)endpoint_name().length(),
-  };
+  serializer.WriteField<glcr::String>(0, endpoint_name_);
 
-  bytes.WriteStringAt(offset + next_extension, endpoint_name());
-  next_extension += endpoint_name_ptr.length;
+  serializer.WriteHeader();
 
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * 0), endpoint_name_ptr);
-
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
-
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status Endpoint::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -170,30 +122,23 @@ glcr::Status Endpoint::ParseFromBytesInternal(const yunq::MessageView& message)
 }
 
 uint64_t Endpoint::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 1);
   // Write endpoint.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), 0);
+  serializer.WriteCapability(0, endpoint_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t Endpoint::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 1;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 1, caps);
   // Write endpoint.
-  caps.WriteAt(next_cap, endpoint());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), next_cap++);
+  serializer.WriteCapability(0, endpoint_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status AhciInfo::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -219,34 +164,27 @@ glcr::Status AhciInfo::ParseFromBytesInternal(const yunq::MessageView& message)
 }
 
 uint64_t AhciInfo::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 2;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 2);
   // Write ahci_region.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), 0);
+  serializer.WriteCapability(0, ahci_region_);
   // Write region_length.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), region_length());
+  serializer.WriteField<uint64_t>(1, region_length_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t AhciInfo::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 2;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 2, caps);
   // Write ahci_region.
-  caps.WriteAt(next_cap, ahci_region());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), next_cap++);
+  serializer.WriteCapability(0, ahci_region_);
   // Write region_length.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), region_length());
+  serializer.WriteField<uint64_t>(1, region_length_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status FramebufferInfo::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -289,72 +227,67 @@ glcr::Status FramebufferInfo::ParseFromBytesInternal(const yunq::MessageView& me
 }
 
 uint64_t FramebufferInfo::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 12;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 12);
   // Write address_phys.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), address_phys());
+  serializer.WriteField<uint64_t>(0, address_phys_);
   // Write width.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), width());
+  serializer.WriteField<uint64_t>(1, width_);
   // Write height.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), height());
+  serializer.WriteField<uint64_t>(2, height_);
   // Write pitch.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 3), pitch());
+  serializer.WriteField<uint64_t>(3, pitch_);
   // Write bpp.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 4), bpp());
+  serializer.WriteField<uint64_t>(4, bpp_);
   // Write memory_model.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 5), memory_model());
+  serializer.WriteField<uint64_t>(5, memory_model_);
   // Write red_mask_size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 6), red_mask_size());
+  serializer.WriteField<uint64_t>(6, red_mask_size_);
   // Write red_mask_shift.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 7), red_mask_shift());
+  serializer.WriteField<uint64_t>(7, red_mask_shift_);
   // Write green_mask_size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 8), green_mask_size());
+  serializer.WriteField<uint64_t>(8, green_mask_size_);
   // Write green_mask_shift.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 9), green_mask_shift());
+  serializer.WriteField<uint64_t>(9, green_mask_shift_);
   // Write blue_mask_size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 10), blue_mask_size());
+  serializer.WriteField<uint64_t>(10, blue_mask_size_);
   // Write blue_mask_shift.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 11), blue_mask_shift());
+  serializer.WriteField<uint64_t>(11, blue_mask_shift_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t FramebufferInfo::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 12;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 12, caps);
   // Write address_phys.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), address_phys());
+  serializer.WriteField<uint64_t>(0, address_phys_);
   // Write width.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), width());
+  serializer.WriteField<uint64_t>(1, width_);
   // Write height.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), height());
+  serializer.WriteField<uint64_t>(2, height_);
   // Write pitch.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 3), pitch());
+  serializer.WriteField<uint64_t>(3, pitch_);
   // Write bpp.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 4), bpp());
+  serializer.WriteField<uint64_t>(4, bpp_);
   // Write memory_model.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 5), memory_model());
+  serializer.WriteField<uint64_t>(5, memory_model_);
   // Write red_mask_size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 6), red_mask_size());
+  serializer.WriteField<uint64_t>(6, red_mask_size_);
   // Write red_mask_shift.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 7), red_mask_shift());
+  serializer.WriteField<uint64_t>(7, red_mask_shift_);
   // Write green_mask_size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 8), green_mask_size());
+  serializer.WriteField<uint64_t>(8, green_mask_size_);
   // Write green_mask_shift.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 9), green_mask_shift());
+  serializer.WriteField<uint64_t>(9, green_mask_shift_);
   // Write blue_mask_size.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 10), blue_mask_size());
+  serializer.WriteField<uint64_t>(10, blue_mask_size_);
   // Write blue_mask_shift.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 11), blue_mask_shift());
+  serializer.WriteField<uint64_t>(11, blue_mask_shift_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 glcr::Status DenaliInfo::ParseFromBytes(const yunq::MessageView& message) {
   RETURN_ERROR(ParseFromBytesInternal(message));
@@ -382,38 +315,31 @@ glcr::Status DenaliInfo::ParseFromBytesInternal(const yunq::MessageView& message
 }
 
 uint64_t DenaliInfo::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
+  yunq::Serializer serializer(bytes, offset, 3);
   // Write denali_endpoint.
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), 0);
+  serializer.WriteCapability(0, denali_endpoint_);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), device_id());
+  serializer.WriteField<uint64_t>(1, device_id_);
   // Write lba_offset.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), lba_offset());
+  serializer.WriteField<uint64_t>(2, lba_offset_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t DenaliInfo::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * 3;
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
+  yunq::Serializer serializer(bytes, offset, 3, caps);
   // Write denali_endpoint.
-  caps.WriteAt(next_cap, denali_endpoint());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 0), next_cap++);
+  serializer.WriteCapability(0, denali_endpoint_);
   // Write device_id.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 1), device_id());
+  serializer.WriteField<uint64_t>(1, device_id_);
   // Write lba_offset.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * 2), lba_offset());
+  serializer.WriteField<uint64_t>(2, lba_offset_);
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 
diff --git a/yunq/message.cpp.jinja b/yunq/message.cpp.jinja
index 403188e..7666bf4 100644
--- a/yunq/message.cpp.jinja
+++ b/yunq/message.cpp.jinja
@@ -73,105 +73,63 @@ glcr::Status {{message.name}}::ParseFromBytesInternal(const yunq::MessageView& m
 }
 
 uint64_t {{message.name}}::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset) const {
-  uint32_t next_extension = header_size + 8 * {{ message.fields | length }};
-  const uint32_t core_size = next_extension;
-
+  yunq::Serializer serializer(bytes, offset, {{ message.fields | length }});
+  
 {%- for field in message.fields %}
   // Write {{field.name}}.
 {%- if not field.repeated %}
-{%- if field.type == Type.U64 %}
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}());
-{%- elif field.type == Type.I64 %}
-  bytes.WriteAt<int64_t>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}());
-{%- elif field.type == Type.STRING %}
-  ExtPointer {{field.name}}_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t){{field.name}}().length(),
-  };
 
-  bytes.WriteStringAt(offset + next_extension, {{field.name}}());
-  next_extension += {{field.name}}_ptr.length;
-
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}_ptr);
-{%- elif field.type == Type.CAPABILITY %}
-  // FIXME: Implement inbuffer capabilities.
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * {{loop.index0}}), 0);
+{%- if field.type != Type.CAPABILITY %}
+  serializer.WriteField<{{field.cpp_type()}}>({{loop.index0}}, {{field.name}}_);
 {%- else %}
-  // TODO: Unimplemented serialization {{field.type}}
+  serializer.WriteCapability({{loop.index0}}, {{field.name}}_);
 {%- endif %}
+
 {%- else %}
-  ExtPointer {{field.name}}_ptr{
-    .offset = next_extension,
-    .length = (uint32_t)({{field.name}}().size() * sizeof({{field.cpp_type()}})),
-  };
 
-  next_extension += {{field.name}}_ptr.length;
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}_ptr);
+{%- if field.type != Type.CAPABILITY %}
+  serializer.WriteRepeated<{{field.cpp_type()}}>({{loop.index0}}, {{field.name}}_);
+{%- else %}
+  serializer.WriteRepeatedCapability({{loop.index0}}, {{field.name}}_);
+{%- endif %}
 
-  for (uint64_t i = 0; i < {{field.name}}().size(); i++) {
-    uint32_t ext_offset = offset + {{field.name}}_ptr.offset + (i * sizeof({{field.cpp_type()}}));
-    bytes.WriteAt<{{field.cpp_type()}}>(ext_offset, {{field.name}}().at(i));
-  }
 {%- endif %}
 {%- endfor %}
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
 
 uint64_t {{message.name}}::SerializeToBytes(glcr::ByteBuffer& bytes, uint64_t offset, glcr::CapBuffer& caps) const {
-  uint32_t next_extension = header_size + 8 * {{ message.fields | length}};
-  const uint32_t core_size = next_extension;
-  uint64_t next_cap = 0;
-
+  yunq::Serializer serializer(bytes, offset, {{ message.fields | length }}, caps);
+  
 {%- for field in message.fields %}
   // Write {{field.name}}.
 {%- if not field.repeated %}
-{%- if field.type == Type.U64 %}
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}());
-{%- elif field.type == Type.I64 %}
-  bytes.WriteAt<int64_t>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}());
-{%- elif field.type == Type.STRING %}
-  ExtPointer {{field.name}}_ptr{
-    .offset = next_extension,
-    // FIXME: Check downcast of str length.
-    .length = (uint32_t){{field.name}}().length(),
-  };
 
-  bytes.WriteStringAt(offset + next_extension, {{field.name}}());
-  next_extension += {{field.name}}_ptr.length;
-
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}_ptr);
-{%- elif field.type == Type.CAPABILITY %}
-  caps.WriteAt(next_cap, {{field.name}}());
-  bytes.WriteAt<uint64_t>(offset + header_size + (8 * {{loop.index0}}), next_cap++);
+{%- if field.type != Type.CAPABILITY %}
+  serializer.WriteField<{{field.cpp_type()}}>({{loop.index0}}, {{field.name}}_);
 {%- else %}
-  // TODO: Unimplemented serialization {{field.type}}
+  serializer.WriteCapability({{loop.index0}}, {{field.name}}_);
 {%- endif %}
+
 {%- else %}
-  ExtPointer {{field.name}}_ptr{
-    .offset = next_extension,
-    .length = (uint32_t)({{field.name}}().size() * sizeof({{field.cpp_type()}})),
-  };
 
-  next_extension += {{field.name}}_ptr.length;
-  bytes.WriteAt<ExtPointer>(offset + header_size + (8 * {{loop.index0}}), {{field.name}}_ptr);
+{%- if field.type != Type.CAPABILITY %}
+  serializer.WriteRepeated<{{field.cpp_type()}}>({{loop.index0}}, {{field.name}}_);
+{%- else %}
+  serializer.WriteRepeatedCapability({{loop.index0}}, {{field.name}}_);
+{%- endif %}
 
-  for (uint64_t i = 0; i < {{field.name}}().size(); i++) {
-    uint32_t ext_offset = offset + {{field.name}}_ptr.offset + (i * sizeof({{field.cpp_type()}}));
-    bytes.WriteAt<{{field.cpp_type()}}>(ext_offset, {{field.name}}().at(i));
-  }
 {%- endif %}
 {%- endfor %}
 
-  // The next extension pointer is the length of the message. 
-  yunq::WriteHeader(bytes, offset, core_size, next_extension);
+  serializer.WriteHeader();
 
-  return next_extension;
+  return serializer.size();
 }
+
 {%- endfor %}
 
 {% if package != None %}