diff --git a/src/shrpx_config.cc b/src/shrpx_config.cc
index a5d89d8d..104c97b6 100644
--- a/src/shrpx_config.cc
+++ b/src/shrpx_config.cc
@@ -54,9 +54,7 @@
 #include "shrpx_log.h"
 #include "shrpx_ssl.h"
 #include "shrpx_http.h"
-#include "http2.h"
 #include "util.h"
-#include "template.h"
 #include "base64.h"
 
 namespace shrpx {
@@ -279,7 +277,7 @@ std::string read_passwd_from_file(const char *filename) {
   return line;
 }
 
-std::pair<std::string, std::string> parse_header(const char *optarg) {
+Headers::value_type parse_header(const char *optarg) {
   const auto *colon = strchr(optarg, ':');
 
   if (colon == nullptr || colon == optarg) {
@@ -290,16 +288,15 @@ std::pair<std::string, std::string> parse_header(const char *optarg) {
   for (; *value == '\t' || *value == ' '; ++value)
     ;
 
-  auto p = std::make_pair(std::string(optarg, colon),
-                          std::string(value, strlen(value)));
-  util::inp_strlower(p.first);
+  auto p =
+      Header(std::string(optarg, colon), std::string(value, strlen(value)));
+  util::inp_strlower(p.name);
 
   if (!nghttp2_check_header_name(
-          reinterpret_cast<const uint8_t *>(p.first.c_str()), p.first.size()) ||
+          reinterpret_cast<const uint8_t *>(p.name.c_str()), p.name.size()) ||
       !nghttp2_check_header_value(
-          reinterpret_cast<const uint8_t *>(p.second.c_str()),
-          p.second.size())) {
-    return {"", ""};
+          reinterpret_cast<const uint8_t *>(p.value.c_str()), p.value.size())) {
+    return Header();
   }
 
   return p;
@@ -2028,7 +2025,7 @@ int parse_config(const char *opt, const char *optarg,
   case SHRPX_OPTID_ADD_REQUEST_HEADER:
   case SHRPX_OPTID_ADD_RESPONSE_HEADER: {
     auto p = parse_header(optarg);
-    if (p.first.empty()) {
+    if (p.name.empty()) {
       LOG(ERROR) << opt << ": invalid header field: " << optarg;
       return -1;
     }
diff --git a/src/shrpx_config.h b/src/shrpx_config.h
index d7b62513..ebc97f8a 100644
--- a/src/shrpx_config.h
+++ b/src/shrpx_config.h
@@ -52,6 +52,7 @@
 
 #include "shrpx_router.h"
 #include "template.h"
+#include "http2.h"
 
 using namespace nghttp2;
 
@@ -461,8 +462,8 @@ struct HttpConfig {
     bool strip_incoming;
   } xff;
   std::vector<AltSvc> altsvcs;
-  std::vector<std::pair<std::string, std::string>> add_request_headers;
-  std::vector<std::pair<std::string, std::string>> add_response_headers;
+  Headers add_request_headers;
+  Headers add_response_headers;
   StringRef server_name;
   size_t request_header_field_buffer;
   size_t max_request_header_fields;
@@ -633,7 +634,7 @@ std::string read_passwd_from_file(const char *filename);
 // like "NAME: VALUE".  We require that NAME is non empty string.  ":"
 // is allowed at the start of the NAME, but NAME == ":" is not
 // allowed.  This function returns pair of NAME and VALUE.
-std::pair<std::string, std::string> parse_header(const char *optarg);
+Headers::value_type parse_header(const char *optarg);
 
 std::vector<LogFragment> parse_log_format(const char *optarg);
 
diff --git a/src/shrpx_config_test.cc b/src/shrpx_config_test.cc
index 1ac82589..eda67e85 100644
--- a/src/shrpx_config_test.cc
+++ b/src/shrpx_config_test.cc
@@ -38,32 +38,32 @@ namespace shrpx {
 
 void test_shrpx_config_parse_header(void) {
   auto p = parse_header("a: b");
-  CU_ASSERT("a" == p.first);
-  CU_ASSERT("b" == p.second);
+  CU_ASSERT("a" == p.name);
+  CU_ASSERT("b" == p.value);
 
   p = parse_header("a:  b");
-  CU_ASSERT("a" == p.first);
-  CU_ASSERT("b" == p.second);
+  CU_ASSERT("a" == p.name);
+  CU_ASSERT("b" == p.value);
 
   p = parse_header(":a: b");
-  CU_ASSERT(p.first.empty());
+  CU_ASSERT(p.name.empty());
 
   p = parse_header("a: :b");
-  CU_ASSERT("a" == p.first);
-  CU_ASSERT(":b" == p.second);
+  CU_ASSERT("a" == p.name);
+  CU_ASSERT(":b" == p.value);
 
   p = parse_header(": b");
-  CU_ASSERT(p.first.empty());
+  CU_ASSERT(p.name.empty());
 
   p = parse_header("alpha: bravo charlie");
-  CU_ASSERT("alpha" == p.first);
-  CU_ASSERT("bravo charlie" == p.second);
+  CU_ASSERT("alpha" == p.name);
+  CU_ASSERT("bravo charlie" == p.value);
 
   p = parse_header("a,: b");
-  CU_ASSERT(p.first.empty());
+  CU_ASSERT(p.name.empty());
 
   p = parse_header("a: b\x0a");
-  CU_ASSERT(p.first.empty());
+  CU_ASSERT(p.name.empty());
 }
 
 void test_shrpx_config_parse_log_format(void) {
diff --git a/src/shrpx_http2_downstream_connection.cc b/src/shrpx_http2_downstream_connection.cc
index 663599af..02982b8a 100644
--- a/src/shrpx_http2_downstream_connection.cc
+++ b/src/shrpx_http2_downstream_connection.cc
@@ -422,7 +422,7 @@ int Http2DownstreamConnection::push_request_headers() {
   }
 
   for (auto &p : httpconf.add_request_headers) {
-    nva.push_back(http2::make_nv_nocopy(p.first, p.second));
+    nva.push_back(http2::make_nv_nocopy(p.name, p.value));
   }
 
   if (LOG_ENABLED(INFO)) {
diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index a08fc588..434873ac 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -1436,7 +1436,7 @@ int Http2Upstream::on_downstream_header_complete(Downstream *downstream) {
   }
 
   for (auto &p : httpconf.add_response_headers) {
-    nva.push_back(http2::make_nv_nocopy(p.first, p.second));
+    nva.push_back(http2::make_nv_nocopy(p.name, p.value));
   }
 
   if (downstream->get_stream_id() % 2 == 0) {
diff --git a/src/shrpx_http_downstream_connection.cc b/src/shrpx_http_downstream_connection.cc
index 40c5753d..8e2796a6 100644
--- a/src/shrpx_http_downstream_connection.cc
+++ b/src/shrpx_http_downstream_connection.cc
@@ -418,9 +418,9 @@ int HttpDownstreamConnection::push_request_headers() {
   }
 
   for (auto &p : httpconf.add_request_headers) {
-    buf->append(p.first);
+    buf->append(p.name);
     buf->append(": ");
-    buf->append(p.second);
+    buf->append(p.value);
     buf->append("\r\n");
   }
 
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index 1794b94c..cc72e8f5 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -1022,9 +1022,9 @@ int HttpsUpstream::on_downstream_header_complete(Downstream *downstream) {
   }
 
   for (auto &p : httpconf.add_response_headers) {
-    buf->append(p.first);
+    buf->append(p.name);
     buf->append(": ");
-    buf->append(p.second);
+    buf->append(p.value);
     buf->append("\r\n");
   }
 
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index 2a9ed64d..a44f2a46 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -1064,8 +1064,8 @@ int SpdyUpstream::on_downstream_header_complete(Downstream *downstream) {
   }
 
   for (auto &p : httpconf.add_response_headers) {
-    nv[hdidx++] = p.first.c_str();
-    nv[hdidx++] = p.second.c_str();
+    nv[hdidx++] = p.name.c_str();
+    nv[hdidx++] = p.value.c_str();
   }
 
   nv[hdidx++] = 0;