diff --git a/src/MessageWriter.cpp b/src/MessageWriter.cpp
index 0c42240e66..d0c2fc12c4 100644
--- a/src/MessageWriter.cpp
+++ b/src/MessageWriter.cpp
@@ -15,7 +15,7 @@ MessageWriter::~MessageWriter() {}
 
 void MessageWriter::WriteKeepAlive() { Write8(NT_MSG_KEEP_ALIVE); }
 
-void MessageWriter::WriteClientHello(const NT_String& self_id) {
+void MessageWriter::WriteClientHello(llvm::StringRef self_id) {
   Write8(NT_MSG_CLIENT_HELLO);
   Write16(m_proto_rev);
   if (m_proto_rev < 0x0300u) return;
@@ -30,7 +30,7 @@ void MessageWriter::WriteProtoUnsup() {
 void MessageWriter::WriteServerHelloDone() { Write8(NT_MSG_SERVER_HELLO_DONE); }
 
 void MessageWriter::WriteServerHello(unsigned int flags,
-                                     const NT_String& self_id) {
+                                     llvm::StringRef self_id) {
   if (m_proto_rev < 0x0300u) return;  // new message in version 3.0
   Write8(NT_MSG_SERVER_HELLO);
   Write8(flags);
@@ -42,7 +42,7 @@ void MessageWriter::WriteClientHelloDone() {
   Write8(NT_MSG_CLIENT_HELLO_DONE);
 }
 
-void MessageWriter::WriteEntryAssign(const NT_String& name, unsigned int id,
+void MessageWriter::WriteEntryAssign(llvm::StringRef name, unsigned int id,
                                      unsigned int seq_num,
                                      const NT_Value& value,
                                      unsigned int flags) {
@@ -85,20 +85,18 @@ void MessageWriter::WriteClearEntries() {
 }
 
 void MessageWriter::WriteExecuteRpc(unsigned int id, unsigned int uid,
-                                    const NT_Value* params_start,
-                                    const NT_Value* params_end) {
-  WriteRpc(NT_MSG_EXECUTE_RPC, id, uid, params_start, params_end);
+                                    llvm::ArrayRef<NT_Value> params) {
+  WriteRpc(NT_MSG_EXECUTE_RPC, id, uid, params);
 }
 
 void MessageWriter::WriteRpcResponse(unsigned int id, unsigned int uid,
-                                     const NT_Value* results_start,
-                                     const NT_Value* results_end) {
-  WriteRpc(NT_MSG_RPC_RESPONSE, id, uid, results_start, results_end);
+                                     llvm::ArrayRef<NT_Value> results) {
+  WriteRpc(NT_MSG_RPC_RESPONSE, id, uid, results);
 }
 
 void MessageWriter::WriteRpc(unsigned int msg_type, unsigned int id,
-                             unsigned int uid, const NT_Value* values_start,
-                             const NT_Value* values_end) {
+                             unsigned int uid,
+                             llvm::ArrayRef<NT_Value> values) {
   if (m_proto_rev < 0x0300u) return;  // new message in version 3.0
 
   Write8(msg_type);
@@ -106,10 +104,8 @@ void MessageWriter::WriteRpc(unsigned int msg_type, unsigned int id,
   Write16(uid);
 
   unsigned long len = 0;
-  for (const NT_Value* value = values_start; value != values_end; ++value)
-    len += GetValueSize(*value);
+  for (auto& value : values) len += GetValueSize(value);
   WriteUleb128(len);
 
-  for (const NT_Value* value = values_start; value != values_end; ++value)
-    WriteValue(*value);
+  for (auto& value : values) WriteValue(value);
 }
diff --git a/src/MessageWriter.h b/src/MessageWriter.h
index 88c8126618..88e4775458 100644
--- a/src/MessageWriter.h
+++ b/src/MessageWriter.h
@@ -10,6 +10,9 @@
 
 #include "WireEncoder.h"
 
+#include "llvm/ArrayRef.h"
+#include "llvm/StringRef.h"
+
 namespace ntimpl {
 
 class MessageWriter : private WireEncoder {
@@ -24,12 +27,12 @@ class MessageWriter : private WireEncoder {
   using WireEncoder::size;
 
   void WriteKeepAlive();
-  void WriteClientHello(const NT_String& self_id);
+  void WriteClientHello(llvm::StringRef self_id);
   void WriteProtoUnsup();
   void WriteServerHelloDone();
-  void WriteServerHello(unsigned int flags, const NT_String& self_id);
+  void WriteServerHello(unsigned int flags, llvm::StringRef self_id);
   void WriteClientHelloDone();
-  void WriteEntryAssign(const NT_String& name, unsigned int id,
+  void WriteEntryAssign(llvm::StringRef name, unsigned int id,
                         unsigned int seq_num, const NT_Value& value,
                         unsigned int flags);
   void WriteEntryUpdate(unsigned int id, unsigned int seq_num,
@@ -38,18 +41,16 @@ class MessageWriter : private WireEncoder {
   void WriteEntryDelete(unsigned int id);
   void WriteClearEntries();
   void WriteExecuteRpc(unsigned int id, unsigned int uid,
-                       const NT_Value* params_start,
-                       const NT_Value* params_end);
+                       llvm::ArrayRef<NT_Value> params);
   void WriteRpcResponse(unsigned int id, unsigned int uid,
-                        const NT_Value* results_start,
-                        const NT_Value* results_end);
+                        llvm::ArrayRef<NT_Value> results);
 
   MessageWriter(const MessageWriter&) = delete;
   MessageWriter& operator=(const MessageWriter&) = delete;
 
  private:
   void WriteRpc(unsigned int msg_type, unsigned int id, unsigned int uid,
-                const NT_Value* values_start, const NT_Value* values_end);
+                llvm::ArrayRef<NT_Value> values);
 };
 
 }  // namespace ntimpl
diff --git a/src/WireEncoder.cpp b/src/WireEncoder.cpp
index f1198b8c79..47fc7c13a5 100644
--- a/src/WireEncoder.cpp
+++ b/src/WireEncoder.cpp
@@ -197,18 +197,18 @@ void WireEncoder::WriteValue(const NT_Value& value) {
   }
 }
 
-std::size_t WireEncoder::GetStringSize(const NT_String& str) const {
+std::size_t WireEncoder::GetStringSize(llvm::StringRef str) const {
   if (m_proto_rev < 0x0300u) {
-    std::size_t len = str.len;
+    std::size_t len = str.size();
     if (len > 0xffff) len = 0xffff; // Limited to 64K length; truncate
     return 2 + len;
   }
-  return SizeUleb128(str.len) + str.len;
+  return SizeUleb128(str.size()) + str.size();
 }
 
-void WireEncoder::WriteString(const NT_String& str) {
+void WireEncoder::WriteString(llvm::StringRef str) {
   // length
-  std::size_t len = str.len;
+  std::size_t len = str.size();
   if (m_proto_rev < 0x0300u) {
     if (len > 0xffff) len = 0xffff; // Limited to 64K length; truncate
     Write16(len);
@@ -217,6 +217,6 @@ void WireEncoder::WriteString(const NT_String& str) {
 
   // contents
   Reserve(len);
-  std::memcpy(m_cur, str.str, len);
+  std::memcpy(m_cur, str.data(), len);
   m_cur += len;
 }
diff --git a/src/WireEncoder.h b/src/WireEncoder.h
index 94de04ff27..487c0f4710 100644
--- a/src/WireEncoder.h
+++ b/src/WireEncoder.h
@@ -13,6 +13,8 @@
 
 #include "ntcore.h"
 
+#include "llvm/StringRef.h"
+
 namespace ntimpl {
 
 /* Encodes native data for network transmission.
@@ -89,7 +91,10 @@ class WireEncoder {
 
   void WriteType(NT_Type type);
   void WriteValue(const NT_Value& value);
-  void WriteString(const NT_String& str);
+  void WriteString(const NT_String& str) {
+    WriteString(llvm::StringRef(str.str, str.len));
+  }
+  void WriteString(llvm::StringRef str);
 
   /* Utility function to get the written size of a value (without actually
    * writing it).
@@ -99,7 +104,10 @@ class WireEncoder {
   /* Utility function to get the written size of a string (without actually
    * writing it).
    */
-  std::size_t GetStringSize(const NT_String& str) const;
+  std::size_t GetStringSize(const NT_String& str) const {
+    return GetStringSize(llvm::StringRef(str.str, str.len));
+  }
+  std::size_t GetStringSize(llvm::StringRef str) const;
 
   WireEncoder(const WireEncoder&) = delete;
   WireEncoder& operator=(const WireEncoder&) = delete;