diff --git a/doc/quickref.xml b/doc/quickref.xml
index 2aa0bcea..8aec0524 100644
--- a/doc/quickref.xml
+++ b/doc/quickref.xml
@@ -41,7 +41,10 @@
           </simplelist>
           <bridgehead renderas="sect3">Type Traits</bridgehead>
           <simplelist type="vert" columns="1">
+           <member><link linkend="beast.ref.http__is_Body">is_Body</link></member>
            <member><link linkend="beast.ref.http__is_Parser">is_Parser</link></member>
+           <member><link linkend="beast.ref.http__is_ReadableBody">is_ReadableBody</link></member>
+           <member><link linkend="beast.ref.http__is_WritableBody">is_WritableBody</link></member>
           </simplelist>
         </entry>
         <entry valign="top">
diff --git a/doc/types/Field.qbk b/doc/types/Field.qbk
index a83309a1..e5d8b22c 100644
--- a/doc/types/Field.qbk
+++ b/doc/types/Field.qbk
@@ -22,7 +22,7 @@ In this table:
     [`boost::string_ref`]
     [
         This function returns a value implicitly convertible to
-        `boost::string_ref` containing the case-insensitve field
+        `boost::string_ref` containing the case-insensitive field
         name, without leading or trailing white space.
     ]
 ]
diff --git a/doc/types/Parser.qbk b/doc/types/Parser.qbk
index fa2b1e9e..0690f23f 100644
--- a/doc/types/Parser.qbk
+++ b/doc/types/Parser.qbk
@@ -38,7 +38,7 @@ In this table:
         an error occurs, the end of the buffer is reached, or a complete
         HTTP/1 message has been parsed. If an error occurs, `ec` is set
         to the error code and parsing stops. This function returns the
-        number of bytes consumed in the input buffer.
+        number of bytes consumed from the input buffer.
     ]
 ]
 [
diff --git a/include/beast/http/concepts.hpp b/include/beast/http/concepts.hpp
new file mode 100644
index 00000000..d8641050
--- /dev/null
+++ b/include/beast/http/concepts.hpp
@@ -0,0 +1,156 @@
+//
+// Copyright (c) 2013-2016 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef BEAST_HTTP_TYPE_CHECK_HPP
+#define BEAST_HTTP_TYPE_CHECK_HPP
+
+#include <beast/core/error.hpp>
+#include <boost/asio/buffer.hpp>
+#include <type_traits>
+#include <utility>
+
+namespace beast {
+namespace http {
+
+namespace detail {
+
+template<class T>
+class has_value_type
+{
+    template<class U, class R =
+        typename U::value_type>
+    static std::true_type check(int);
+    template<class>
+    static std::false_type check(...);
+    using type = decltype(check<T>(0));
+public:
+    static bool constexpr value = type::value;
+};
+
+template<class T, bool B = has_value_type<T>::value>
+struct extract_value_type
+{
+    using type = void;
+};
+
+template<class T>
+struct extract_value_type<T, true>
+{
+    using type = typename T::value_type;
+};
+
+template<class T>
+class has_reader
+{
+    template<class U, class R =
+        typename U::reader>
+    static std::true_type check(int);
+    template<class>
+    static std::false_type check(...);
+public:
+    using type = decltype(check<T>(0));
+};
+
+template<class T>
+class has_writer
+{
+    template<class U, class R =
+        typename U::writer>
+    static std::true_type check(int);
+    template<class>
+    static std::false_type check(...);
+public:
+    using type = decltype(check<T>(0));
+};
+
+template<class T>
+struct is_Body
+{
+    using type = std::integral_constant<bool,
+        has_value_type<T>::value &&
+        std::is_default_constructible<
+            typename extract_value_type<T>::type>::value
+    >;
+};
+
+template<class T>
+class is_Parser
+{
+    template<class U, class R =
+        std::is_convertible<decltype(
+            std::declval<U>().complete()),
+            bool>>
+    static R check1(int);
+    template<class>
+    static std::false_type check1(...);
+    using type1 = decltype(check1<T>(0));
+
+    template<class U, class R =
+        std::is_convertible<decltype(
+            std::declval<U>().write(
+                std::declval<boost::asio::const_buffer const&>(),
+                std::declval<error_code&>())),
+            std::size_t>>
+    static R check2(int);
+    template<class>
+    static std::false_type check2(...);
+    using type2 = decltype(check2<T>(0));
+
+    template<class U, class R = decltype(
+        std::declval<U>().write_eof(std::declval<error_code&>()),
+            std::true_type{})>
+    static R check3(int);
+    template<class>
+    static std::false_type check3(...);
+    using type3 = decltype(check3<T>(0));
+
+public:
+    using type = std::integral_constant<bool,
+        type1::value &&
+        type2::value &&
+        type3::value
+    >;
+};
+
+} // detail
+
+/// Determine if `T` meets the requirements of `Body`.
+template<class T>
+#if GENERATING_DOCS
+struct is_Body : std::integral_constant<bool, ...>{};
+#else
+using is_Body = typename detail::is_Body<T>::type;
+#endif
+
+/// Determine if `T` meets the requirements of `ReadableBody`.
+template<class T>
+#if GENERATING_DOCS
+struct is_ReadableBody : std::integral_constant<bool, ...>{};
+#else
+using is_ReadableBody = typename detail::has_reader<T>::type;
+#endif
+
+/// Determine if `T` meets the requirements of `WritableBody`.
+template<class T>
+#if GENERATING_DOCS
+struct is_WritableBody : std::integral_constant<bool, ...>{};
+#else
+using is_WritableBody = typename detail::has_writer<T>::type;
+#endif
+
+/// Determine if `T` meets the requirements of `Parser`.
+template<class T>
+#if GENERATING_DOCS
+struct is_Parser : std::integral_constant<bool, ...>{};
+#else
+using is_Parser = typename detail::is_Parser<T>::type;
+#endif
+
+} // http
+} // beast
+
+#endif
diff --git a/include/beast/http/empty_body.hpp b/include/beast/http/empty_body.hpp
index 885a5605..8eb44064 100644
--- a/include/beast/http/empty_body.hpp
+++ b/include/beast/http/empty_body.hpp
@@ -34,20 +34,6 @@ struct empty_body
 private:
 #endif
 
-    struct reader
-    {
-        template<bool isRequest, class Headers>
-        explicit
-        reader(message<isRequest, empty_body, Headers>&)
-        {
-        }
-
-        void
-        write(void const*, std::size_t, error_code&)
-        {
-        }
-    };
-
     struct writer
     {
         writer(writer const&) = delete;
diff --git a/include/beast/http/impl/read.ipp b/include/beast/http/impl/read.ipp
index 87c0af4c..0d22a4b5 100644
--- a/include/beast/http/impl/read.ipp
+++ b/include/beast/http/impl/read.ipp
@@ -8,8 +8,8 @@
 #ifndef BEAST_HTTP_IMPL_READ_IPP_HPP
 #define BEAST_HTTP_IMPL_READ_IPP_HPP
 
+#include <beast/http/concepts.hpp>
 #include <beast/http/parser_v1.hpp>
-#include <beast/http/type_check.hpp>
 #include <beast/core/bind_handler.hpp>
 #include <beast/core/handler_alloc.hpp>
 #include <beast/core/stream_concepts.hpp>
@@ -323,6 +323,12 @@ void
 parse(SyncReadStream& stream,
     Streambuf& streambuf, Parser& parser)
 {
+    static_assert(is_SyncReadStream<SyncReadStream>::value,
+        "SyncReadStream requirements not met");
+    static_assert(is_Streambuf<Streambuf>::value,
+        "Streambuf requirements not met");
+    static_assert(is_Parser<Parser>::value,
+        "Parser requirements not met");
     error_code ec;
     parse(stream, streambuf, parser, ec);
     if(ec)
@@ -403,6 +409,8 @@ read(SyncReadStream& stream, Streambuf& streambuf,
         "SyncReadStream requirements not met");
     static_assert(is_Streambuf<Streambuf>::value,
         "Streambuf requirements not met");
+    static_assert(is_ReadableBody<Body>::value,
+        "ReadableBody requirements not met");
     error_code ec;
     read(stream, streambuf, msg, ec);
     if(ec)
@@ -420,6 +428,8 @@ read(SyncReadStream& stream, Streambuf& streambuf,
         "SyncReadStream requirements not met");
     static_assert(is_Streambuf<Streambuf>::value,
         "Streambuf requirements not met");
+    static_assert(is_ReadableBody<Body>::value,
+        "ReadableBody requirements not met");
     parser_v1<isRequest, Body, Headers> p;
     parse(stream, streambuf, p, ec);
     if(ec)
@@ -441,6 +451,8 @@ async_read(AsyncReadStream& stream, Streambuf& streambuf,
         "AsyncReadStream requirements not met");
     static_assert(is_Streambuf<Streambuf>::value,
         "Streambuf requirements not met");
+    static_assert(is_ReadableBody<Body>::value,
+        "ReadableBody requirements not met");
     beast::async_completion<ReadHandler,
         void(error_code)> completion(handler);
     detail::read_op<AsyncReadStream, Streambuf,
diff --git a/include/beast/http/impl/write.ipp b/include/beast/http/impl/write.ipp
index 8153dfc9..bb08c038 100644
--- a/include/beast/http/impl/write.ipp
+++ b/include/beast/http/impl/write.ipp
@@ -8,6 +8,7 @@
 #ifndef BEAST_HTTP_IMPL_WRITE_IPP
 #define BEAST_HTTP_IMPL_WRITE_IPP
 
+#include <beast/http/concepts.hpp>
 #include <beast/http/resume_context.hpp>
 #include <beast/http/detail/chunk_encode.hpp>
 #include <beast/http/detail/has_content_length.hpp>
@@ -448,6 +449,8 @@ write(SyncWriteStream& stream,
 {
     static_assert(is_SyncWriteStream<SyncWriteStream>::value,
         "SyncWriteStream requirements not met");
+    static_assert(is_WritableBody<Body>::value,
+        "WritableBody requirements not met");
     error_code ec;
     write(stream, msg, ec);
     if(ec)
@@ -463,6 +466,8 @@ write(SyncWriteStream& stream,
 {
     static_assert(is_SyncWriteStream<SyncWriteStream>::value,
         "SyncWriteStream requirements not met");
+    static_assert(is_WritableBody<Body>::value,
+        "WritableBody requirements not met");
     detail::write_preparation<isRequest, Body, Headers> wp(msg);
     wp.init(ec);
     if(ec)
@@ -546,6 +551,8 @@ async_write(AsyncWriteStream& stream,
     static_assert(
         is_AsyncWriteStream<AsyncWriteStream>::value,
             "AsyncWriteStream requirements not met");
+    static_assert(is_WritableBody<Body>::value,
+        "WritableBody requirements not met");
     beast::async_completion<WriteHandler,
         void(error_code)> completion(handler);
     detail::write_op<AsyncWriteStream, decltype(completion.handler),
@@ -607,6 +614,8 @@ std::ostream&
 operator<<(std::ostream& os,
     message_v1<isRequest, Body, Headers> const& msg)
 {
+    static_assert(is_WritableBody<Body>::value,
+        "WritableBody requirements not met");
     detail::ostream_SyncStream oss(os);
     error_code ec;
     write(oss, msg, ec);
diff --git a/include/beast/http/parser_v1.hpp b/include/beast/http/parser_v1.hpp
index 8831297a..46f8dee8 100644
--- a/include/beast/http/parser_v1.hpp
+++ b/include/beast/http/parser_v1.hpp
@@ -9,6 +9,7 @@
 #define BEAST_HTTP_PARSER_V1_HPP
 
 #include <beast/http/basic_parser_v1.hpp>
+#include <beast/http/concepts.hpp>
 #include <beast/http/message_v1.hpp>
 #include <beast/core/error.hpp>
 #include <functional>
@@ -54,6 +55,9 @@ public:
         message_v1<isRequest, Body, Headers>;
 
 private:
+    static_assert(is_ReadableBody<Body>::value,
+        "ReadableBody requirements not met");
+
     std::string field_;
     std::string value_;
     message_type m_;
diff --git a/include/beast/http/type_check.hpp b/include/beast/http/type_check.hpp
deleted file mode 100644
index 180e1b7d..00000000
--- a/include/beast/http/type_check.hpp
+++ /dev/null
@@ -1,60 +0,0 @@
-//
-// Copyright (c) 2013-2016 Vinnie Falco (vinnie dot falco at gmail dot com)
-//
-// Distributed under the Boost Software License, Version 1.0. (See accompanying
-// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-//
-
-#ifndef BEAST_HTTP_TYPE_CHECK_HPP
-#define BEAST_HTTP_TYPE_CHECK_HPP
-
-#include <beast/core/error.hpp>
-#include <boost/asio/buffer.hpp>
-#include <type_traits>
-#include <utility>
-
-namespace beast {
-namespace http {
-
-/// Determine if `T` meets the requirements of `Parser`.
-template<class T>
-class is_Parser
-{
-    template<class U, class R =
-        std::is_convertible<decltype(
-            std::declval<U>().complete()),
-            bool>>
-    static R check1(int);
-    template<class>
-    static std::false_type check1(...);
-    using type1 = decltype(check1<T>(0));
-
-    template<class U, class R =
-        std::is_convertible<decltype(
-            std::declval<U>().write(
-                std::declval<boost::asio::const_buffer const&>(),
-                std::declval<error_code&>())),
-            std::size_t>>
-    static R check2(int);
-    template<class>
-    static std::false_type check2(...);
-    using type2 = decltype(check2<T>(0));
-
-    template<class U, class R = decltype(
-        std::declval<U>().write_eof(std::declval<error_code&>()),
-            std::true_type{})>
-    static R check3(int);
-    template<class>
-    static std::false_type check3(...);
-    using type3 = decltype(check3<T>(0));
-
-public:
-    /// `true` if `T` meets the requirements.
-    static bool const value =
-        type1::value && type2::value && type3::value;
-};
-
-} // http
-} // beast
-
-#endif
diff --git a/include/beast/websocket/impl/accept_op.ipp b/include/beast/websocket/impl/accept_op.ipp
index e575f2f8..bc94ac35 100644
--- a/include/beast/websocket/impl/accept_op.ipp
+++ b/include/beast/websocket/impl/accept_op.ipp
@@ -33,7 +33,7 @@ class stream<NextLayer>::accept_op
     struct data
     {
         stream<NextLayer>& ws;
-        http::request_v1<http::empty_body> req;
+        http::request_v1<http::string_body> req;
         Handler h;
         bool cont;
         int state = 0;
diff --git a/include/beast/websocket/impl/stream.ipp b/include/beast/websocket/impl/stream.ipp
index d914542a..569f43b6 100644
--- a/include/beast/websocket/impl/stream.ipp
+++ b/include/beast/websocket/impl/stream.ipp
@@ -253,7 +253,7 @@ accept(ConstBufferSequence const& buffers, error_code& ec)
     stream_.buffer().commit(buffer_copy(
         stream_.buffer().prepare(
             buffer_size(buffers)), buffers));
-    http::request_v1<http::empty_body> m;
+    http::request_v1<http::string_body> m;
     http::read(next_layer(), stream_.buffer(), m, ec);
     if(ec)
         return;
diff --git a/test/Jamfile b/test/Jamfile
index a5821367..02fb70a1 100644
--- a/test/Jamfile
+++ b/test/Jamfile
@@ -44,6 +44,7 @@ unit-test http-tests :
     http/basic_headers.cpp
     http/basic_parser_v1.cpp
     http/body_type.cpp
+    http/concepts.cpp
     http/empty_body.cpp
     http/headers.cpp
     http/message.cpp
@@ -58,7 +59,6 @@ unit-test http-tests :
     http/status.cpp
     http/streambuf_body.cpp
     http/string_body.cpp
-    http/type_check.cpp
     http/write.cpp
     http/detail/chunk_encode.cpp
     ;
diff --git a/test/core/buffer_cat.cpp b/test/core/buffer_cat.cpp
index c943e416..c78f75c6 100644
--- a/test/core/buffer_cat.cpp
+++ b/test/core/buffer_cat.cpp
@@ -66,6 +66,14 @@ public:
             expect(buffer_size(buffer_cat(
                 sb1.data(), sb2.data())) == 12);
         }
+        for(auto it = bs.begin(); it != bs.end(); ++it)
+        {
+            decltype(bs)::const_iterator copy;
+            copy = it;
+            expect(copy == it);
+            copy = copy;
+            expect(copy == it);
+        }
     }
 
     void testIterators()
diff --git a/test/http/CMakeLists.txt b/test/http/CMakeLists.txt
index f3959b5b..6b2b8c37 100644
--- a/test/http/CMakeLists.txt
+++ b/test/http/CMakeLists.txt
@@ -10,6 +10,7 @@ add_executable (http-tests
     basic_headers.cpp
     basic_parser_v1.cpp
     body_type.cpp
+    concepts.cpp
     empty_body.cpp
     headers.cpp
     message.cpp
@@ -24,7 +25,6 @@ add_executable (http-tests
     status.cpp
     streambuf_body.cpp
     string_body.cpp
-    type_check.cpp
     write.cpp
     detail/chunk_encode.cpp
 )
diff --git a/test/http/type_check.cpp b/test/http/concepts.cpp
similarity index 88%
rename from test/http/type_check.cpp
rename to test/http/concepts.cpp
index 82020206..e540397b 100644
--- a/test/http/type_check.cpp
+++ b/test/http/concepts.cpp
@@ -6,4 +6,4 @@
 //
 
 // Test that header file is self-contained.
-#include <beast/http/type_check.hpp>
+#include <beast/http/concepts.hpp>
diff --git a/test/http/streambuf_body.cpp b/test/http/streambuf_body.cpp
index a036af6b..33ac29b7 100644
--- a/test/http/streambuf_body.cpp
+++ b/test/http/streambuf_body.cpp
@@ -12,8 +12,10 @@
 #include <beast/http/headers.hpp>
 #include <beast/http/parser_v1.hpp>
 #include <beast/http/read.hpp>
+#include <beast/http/write.hpp>
 #include <beast/test/string_stream.hpp>
 #include <beast/unit_test/suite.hpp>
+#include <boost/lexical_cast.hpp>
 
 namespace beast {
 namespace http {
@@ -25,16 +27,18 @@ class streambuf_body_test : public beast::unit_test::suite
 public:
     void run() override
     {
-        test::string_stream ss(ios_,
+        std::string const s =
             "HTTP/1.1 200 OK\r\n"
             "Server: test\r\n"
             "Content-Length: 3\r\n"
             "\r\n"
-            "xyz");
+            "xyz";
+        test::string_stream ss(ios_, s);
         parser_v1<false, streambuf_body, headers> p;
         streambuf sb;
         parse(ss, sb, p);
         expect(to_string(p.get().body.data()) == "xyz");
+        expect(boost::lexical_cast<std::string>(p.get()) == s);
     }
 };