diff --git a/include/boost/http_proto/impl/sink.hpp b/include/boost/http_proto/impl/sink.hpp
index dffa5fb5..aa064261 100644
--- a/include/boost/http_proto/impl/sink.hpp
+++ b/include/boost/http_proto/impl/sink.hpp
@@ -10,7 +10,7 @@
 #ifndef BOOST_HTTP_PROTO_IMPL_SINK_HPP
 #define BOOST_HTTP_PROTO_IMPL_SINK_HPP
 
-#include <boost/buffers/mutable_buffer.hpp>
+#include <boost/buffers/buffer.hpp>
 #include <boost/buffers/range.hpp>
 #include <boost/http_proto/detail/except.hpp>
 #include <boost/assert.hpp>
@@ -59,10 +59,11 @@ write_impl(
             p != tmp_end &&
             it != end_);
         rv += on_write(
-            buffers::const_buffer_span(
-                tmp, p - tmp),
-            it != end_ ||
-                more);
+            true,
+            boost::span<
+                buffers::const_buffer const>(
+                    tmp, p - tmp),
+            it != end_ || more);
         if(rv.ec.failed())
             return rv;
     }
diff --git a/include/boost/http_proto/impl/source.hpp b/include/boost/http_proto/impl/source.hpp
index d7f569c1..dbfdf36d 100644
--- a/include/boost/http_proto/impl/source.hpp
+++ b/include/boost/http_proto/impl/source.hpp
@@ -11,8 +11,6 @@
 #define BOOST_BUFFERS_IMPL_SOURCE_HPP
 
 #include <boost/http_proto/detail/except.hpp>
-#include <boost/buffers/range.hpp>
-#include <boost/buffers/type_traits.hpp>
 #include <boost/assert.hpp>
 
 namespace boost {
@@ -61,8 +59,10 @@ read_impl(
             p != tmp_end &&
             it != end_);
         rv += on_read(
-            buffers::mutable_buffer_span(
-                tmp, p - tmp));
+            true,
+            boost::span<
+                buffers::mutable_buffer const>(
+                    tmp, p - tmp));
         if(rv.ec.failed())
             return rv;
         if(rv.finished)
diff --git a/include/boost/http_proto/parser.hpp b/include/boost/http_proto/parser.hpp
index 3943c8d7..5a347eb8 100644
--- a/include/boost/http_proto/parser.hpp
+++ b/include/boost/http_proto/parser.hpp
@@ -18,10 +18,9 @@
 #include <boost/http_proto/header_limits.hpp>
 #include <boost/http_proto/sink.hpp>
 
-#include <boost/buffers/any_dynamic_buffer.hpp>
-#include <boost/buffers/mutable_buffer_pair.hpp>
-#include <boost/buffers/mutable_buffer_span.hpp>
-#include <boost/buffers/type_traits.hpp>
+#include <boost/buffers/dynamic_buffer.hpp>
+#include <boost/buffers/buffer_pair.hpp>
+#include <boost/core/span.hpp>
 #include <boost/rts/context_fwd.hpp>
 
 #include <cstddef>
@@ -77,12 +76,12 @@ class parser
     /** The type of buffer returned from @ref prepare.
     */
     using mutable_buffers_type =
-        buffers::mutable_buffer_span;
+        boost::span<buffers::mutable_buffer const>;
 
     /** The type of buffer returned from @ref pull_body.
     */
     using const_buffers_type =
-        buffers::const_buffer_span;
+        boost::span<buffers::const_buffer const>;
 
     //--------------------------------------------
     //
diff --git a/include/boost/http_proto/serializer.hpp b/include/boost/http_proto/serializer.hpp
index 8337b978..0d3fbfc0 100644
--- a/include/boost/http_proto/serializer.hpp
+++ b/include/boost/http_proto/serializer.hpp
@@ -15,9 +15,8 @@
 #include <boost/http_proto/detail/workspace.hpp>
 #include <boost/http_proto/source.hpp>
 
-#include <boost/buffers/const_buffer_span.hpp>
-#include <boost/buffers/mutable_buffer_pair.hpp>
-#include <boost/buffers/type_traits.hpp>
+#include <boost/buffers/buffer_pair.hpp>
+#include <boost/core/span.hpp>
 #include <boost/rts/context_fwd.hpp>
 #include <boost/system/result.hpp>
 
@@ -65,7 +64,7 @@ class serializer
         area.
     */
     using const_buffers_type =
-        buffers::const_buffer_span;
+        boost::span<buffers::const_buffer const>;
 
     /** Constructor.
 
diff --git a/include/boost/http_proto/sink.hpp b/include/boost/http_proto/sink.hpp
index 01ba5bba..f49b9299 100644
--- a/include/boost/http_proto/sink.hpp
+++ b/include/boost/http_proto/sink.hpp
@@ -11,8 +11,8 @@
 #define BOOST_HTTP_PROTO_SINK_HPP
 
 #include <boost/http_proto/detail/config.hpp>
-#include <boost/buffers/const_buffer_span.hpp>
-#include <boost/buffers/type_traits.hpp>
+#include <boost/buffers/buffer.hpp>
+#include <boost/core/span.hpp>
 #include <boost/system/error_code.hpp>
 #include <cstddef>
 #include <type_traits>
@@ -192,7 +192,8 @@ struct BOOST_SYMBOL_VISIBLE
     virtual
     results
     on_write(
-        buffers::const_buffer_span bs,
+        bool boost_span_issue_202_workaround,
+        boost::span<const buffers::const_buffer> bs,
         bool more);
 
 private:
@@ -212,13 +213,13 @@ struct BOOST_SYMBOL_VISIBLE
         return on_write(b, more);
     }
 
-    results
-    write_impl(
-        buffers::const_buffer_span const& bs,
-        bool more)
-    {
-        return on_write(bs, more);
-    }
+    // results
+    // write_impl(
+    //     boost::span<const buffers::const_buffer> const& bs,
+    //     bool more)
+    // {
+    //     return on_write(bs, more);
+    // }
 
     template<class T>
     results
diff --git a/include/boost/http_proto/source.hpp b/include/boost/http_proto/source.hpp
index 853ffebf..e8b9e5c1 100644
--- a/include/boost/http_proto/source.hpp
+++ b/include/boost/http_proto/source.hpp
@@ -11,8 +11,8 @@
 #define BOOST_HTTP_PROTO_SOURCE_HPP
 
 #include <boost/http_proto/detail/config.hpp>
-#include <boost/buffers/mutable_buffer_span.hpp>
-#include <boost/buffers/type_traits.hpp>
+#include <boost/buffers/buffer.hpp>
+#include <boost/core/span.hpp>
 #include <boost/system/error_code.hpp>
 #include <cstddef>
 #include <type_traits>
@@ -195,7 +195,8 @@ struct BOOST_SYMBOL_VISIBLE
     virtual
     results
     on_read(
-        buffers::mutable_buffer_span bs);
+        bool boost_span_issue_202_workaround,
+        boost::span<buffers::mutable_buffer const> bs);
 
 private:
     results
@@ -205,12 +206,12 @@ struct BOOST_SYMBOL_VISIBLE
         return on_read(b);
     }
 
-    results
-    read_impl(
-        buffers::mutable_buffer_span const& bs)
-    {
-        return on_read(bs);
-    }
+    // results
+    // read_impl(
+    //     boost::span<buffers::mutable_buffer const> const& bs)
+    // {
+    //     return on_read(bs);
+    // }
 
     template<class T>
     results
diff --git a/include/boost/http_proto/string_body.hpp b/include/boost/http_proto/string_body.hpp
index 6dac063e..6242bd79 100644
--- a/include/boost/http_proto/string_body.hpp
+++ b/include/boost/http_proto/string_body.hpp
@@ -11,7 +11,7 @@
 #define BOOST_HTTP_PROTO_STRING_BODY_HPP
 
 #include <boost/http_proto/detail/config.hpp>
-#include <boost/buffers/const_buffer.hpp>
+#include <boost/buffers/buffer.hpp>
 #include <string>
 #include <utility>
 
diff --git a/src/detail/array_of_const_buffers.cpp b/src/detail/array_of_const_buffers.cpp
index 91a51bc2..17e9f67c 100644
--- a/src/detail/array_of_const_buffers.cpp
+++ b/src/detail/array_of_const_buffers.cpp
@@ -12,7 +12,7 @@
 
 #include <boost/http_proto/detail/except.hpp>
 
-#include <boost/buffers/sans_prefix.hpp>
+#include <boost/buffers/slice.hpp>
 
 namespace boost {
 namespace http_proto {
@@ -38,7 +38,7 @@ consume(std::size_t n)
         auto* p = base_ + pos_;
         if(n < p->size())
         {
-            *p = buffers::sans_prefix(*p, n);
+            buffers::trim_front(*p, n);
             return;
         }
         n -= p->size();
diff --git a/src/detail/array_of_const_buffers.hpp b/src/detail/array_of_const_buffers.hpp
index 4bdece43..0db72cb9 100644
--- a/src/detail/array_of_const_buffers.hpp
+++ b/src/detail/array_of_const_buffers.hpp
@@ -11,7 +11,8 @@
 #ifndef BOOST_HTTP_PROTO_DETAIL_ARRAY_OF_BUFFERS_HPP
 #define BOOST_HTTP_PROTO_DETAIL_ARRAY_OF_BUFFERS_HPP
 
-#include <boost/buffers/const_buffer.hpp>
+#include <boost/assert.hpp>
+#include <boost/buffers/buffer.hpp>
 
 #include <cstdint>
 
diff --git a/src/detail/buffer_utils.hpp b/src/detail/buffer_utils.hpp
new file mode 100644
index 00000000..64c6d6a6
--- /dev/null
+++ b/src/detail/buffer_utils.hpp
@@ -0,0 +1,44 @@
+//
+// Copyright (c) 2025 Mohammad Nejati
+//
+// 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)
+//
+// Official repository: https://github.com/cppalliance/http_proto
+//
+
+#ifndef BOOST_HTTP_PROTO_DETAIL_BUFFER_UTILS_HPP
+#define BOOST_HTTP_PROTO_DETAIL_BUFFER_UTILS_HPP
+
+#include <boost/buffers/buffer.hpp>
+#include <boost/buffers/slice.hpp>
+#include <boost/core/span.hpp>
+
+namespace boost {
+namespace http_proto {
+namespace detail {
+
+template<
+    typename BufferSequence,
+    typename Buffer = typename BufferSequence::value_type>
+boost::span<Buffer const>
+make_span(BufferSequence const& mbp)
+{
+    return { mbp.begin(), mbp.end() };
+}
+
+template<typename BufferSequence>
+BufferSequence
+prefix(
+    BufferSequence cbp,
+    std::size_t n)
+{
+    buffers::keep_front(cbp, n);
+    return cbp;
+}
+
+} // detail
+} // http_proto
+} // boost
+
+#endif
diff --git a/src/detail/filter.cpp b/src/detail/filter.cpp
index 26ede36c..a6173862 100644
--- a/src/detail/filter.cpp
+++ b/src/detail/filter.cpp
@@ -11,8 +11,6 @@
 #include "src/detail/filter.hpp"
 
 #include <boost/buffers/front.hpp>
-#include <boost/buffers/sans_prefix.hpp>
-#include <boost/buffers/size.hpp>
 
 namespace boost {
 namespace http_proto {
@@ -21,7 +19,8 @@ namespace detail {
 auto
 filter::
 process(
-    buffers::mutable_buffer_subspan out,
+    buffers::slice_of<
+        boost::span<const buffers::mutable_buffer>> out,
     buffers::const_buffer_pair in,
     bool more) -> results
 {
@@ -58,8 +57,8 @@ process(
             return rv;
         }
 
-        out = buffers::sans_prefix(out, rs.out_bytes);
-        in  = buffers::sans_prefix(in, rs.in_bytes);
+        buffers::trim_front(out, rs.out_bytes);
+        buffers::trim_front(in, rs.in_bytes);
 
         if(buffers::size(out) == 0)
             return rv;
diff --git a/src/detail/filter.hpp b/src/detail/filter.hpp
index 20262647..373e0010 100644
--- a/src/detail/filter.hpp
+++ b/src/detail/filter.hpp
@@ -11,8 +11,9 @@
 #ifndef BOOST_HTTP_PROTO_DETAIL_FILTER_HPP
 #define BOOST_HTTP_PROTO_DETAIL_FILTER_HPP
 
-#include <boost/buffers/const_buffer_pair.hpp>
-#include <boost/buffers/mutable_buffer_subspan.hpp>
+#include <boost/buffers/buffer_pair.hpp>
+#include <boost/buffers/slice.hpp>
+#include <boost/core/span.hpp>
 #include <boost/system/error_code.hpp>
 
 namespace boost {
@@ -62,7 +63,8 @@ class filter
 
     results
     process(
-        buffers::mutable_buffer_subspan out,
+        buffers::slice_of<
+            boost::span<const buffers::mutable_buffer>> out,
         buffers::const_buffer_pair in,
         bool more);
 
diff --git a/src/parser.cpp b/src/parser.cpp
index 4df14db1..b82db336 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -13,6 +13,7 @@
 #include <boost/http_proto/parser.hpp>
 
 #include "src/detail/brotli_filter_base.hpp"
+#include "src/detail/buffer_utils.hpp"
 #include "src/detail/zlib_filter_base.hpp"
 
 #include <boost/assert.hpp>
@@ -20,9 +21,6 @@
 #include <boost/buffers/copy.hpp>
 #include <boost/buffers/flat_buffer.hpp>
 #include <boost/buffers/front.hpp>
-#include <boost/buffers/make_buffer.hpp>
-#include <boost/buffers/prefix.hpp>
-#include <boost/buffers/size.hpp>
 #include <boost/rts/brotli/decode.hpp>
 #include <boost/rts/context.hpp>
 #include <boost/rts/zlib/error.hpp>
@@ -789,7 +787,7 @@ class parser::impl
                 n = clamp(n, svc_.cfg.max_prepare);
                 nprepare_ = n;
                 mbp_ = cb0_.prepare(n);
-                return mutable_buffers_type(mbp_);
+                return detail::make_span(mbp_);
             }
             else
             {
@@ -829,7 +827,7 @@ class parser::impl
 
                     nprepare_ = n;
                     mbp_ = cb0_.prepare(n);
-                    return mutable_buffers_type(mbp_);
+                    return detail::make_span(mbp_);
                 }
                 case style::elastic:
                 {
@@ -871,7 +869,7 @@ class parser::impl
                             // we can detect overflow
                             nprepare_ = 1;
                             mbp_ = cb0_.prepare(1);
-                            return mutable_buffers_type(mbp_);
+                            return detail::make_span(mbp_);
                         }
                     }
 
@@ -1319,7 +1317,7 @@ class parser::impl
                         const std::size_t chunk_avail =
                             clamp(chunk_remain_, cb0_.size());
                         const auto chunk =
-                            buffers::prefix(cb0_.data(), chunk_avail);
+                            detail::prefix(cb0_.data(), chunk_avail);
 
                         if(body_limit_remain() < chunk_avail)
                         {
@@ -1461,9 +1459,7 @@ class parser::impl
                         payload_remain_ -= payload_avail;
                         body_total_     += payload_avail;
                         auto sink_rs = sink_->write(
-                            buffers::prefix(
-                                cb0_.data(),
-                                payload_avail),
+                            detail::prefix(cb0_.data(), payload_avail),
                             !is_complete);
                         cb0_.consume(sink_rs.bytes);
                         if(sink_rs.ec.failed())
@@ -1541,9 +1537,7 @@ class parser::impl
             case style::sink:
             {
                 auto rs = sink_->write(
-                    buffers::prefix(
-                        body_buf.data(),
-                        body_avail_),
+                    detail::prefix(body_buf.data(), body_avail_),
                     state_ == state::set_body);
                 body_buf.consume(rs.bytes);
                 body_avail_ -= rs.bytes;
@@ -1600,10 +1594,10 @@ class parser::impl
             return {};
         case state::body:
         case state::complete_in_place:
-            cbp_ = buffers::prefix(
+            cbp_ = detail::prefix(
                 (is_plain() ? cb0_ : cb1_).data(),
                 body_avail_);
-            return const_buffers_type(cbp_);
+            return detail::make_span(cbp_);
         default:
             detail::throw_logic_error();
         }
@@ -1736,9 +1730,7 @@ class parser::impl
 
                     return filter_->process(
                         eb_->prepare(n),
-                        buffers::prefix(
-                            cb0_.data(),
-                            payload_avail),
+                        detail::prefix(cb0_.data(), payload_avail),
                         more);
                 }
                 else // in-place and sink 
@@ -1747,10 +1739,8 @@ class parser::impl
                     n = clamp(n, cb1_.capacity());
 
                     return filter_->process(
-                        buffers::mutable_buffer_span{ cb1_.prepare(n) },
-                        buffers::prefix(
-                            cb0_.data(),
-                            payload_avail),
+                        detail::make_span(cb1_.prepare(n)),
+                        detail::prefix(cb0_.data(), payload_avail),
                         more);
                 }
             }();
diff --git a/src/serializer.cpp b/src/serializer.cpp
index 82813edf..d8e00a5e 100644
--- a/src/serializer.cpp
+++ b/src/serializer.cpp
@@ -16,14 +16,11 @@
 
 #include "src/detail/array_of_const_buffers.hpp"
 #include "src/detail/brotli_filter_base.hpp"
+#include "src/detail/buffer_utils.hpp"
 #include "src/detail/zlib_filter_base.hpp"
 
 #include <boost/buffers/circular_buffer.hpp>
 #include <boost/buffers/copy.hpp>
-#include <boost/buffers/prefix.hpp>
-#include <boost/buffers/sans_prefix.hpp>
-#include <boost/buffers/sans_suffix.hpp>
-#include <boost/buffers/size.hpp>
 #include <boost/core/bit.hpp>
 #include <boost/core/ignore_unused.hpp>
 #include <boost/rts/brotli/encode.hpp>
@@ -396,9 +393,7 @@ class serializer::impl
                         }
                     }
                 }
-                return const_buffers_type(
-                    prepped_.begin(),
-                    prepped_.size());
+                return detail::make_span(prepped_);
             }
 
             case style::source:
@@ -444,8 +439,7 @@ class serializer::impl
                     break;
 
                 const auto rs = filter_->process(
-                    buffers::mutable_buffer_span(
-                        out_prepare()),
+                    detail::make_span(out_prepare()),
                     {}, // empty input
                     false);
 
@@ -479,8 +473,7 @@ class serializer::impl
                     }
 
                     const auto rs = filter_->process(
-                        buffers::mutable_buffer_span(
-                            out_prepare()),
+                        detail::make_span(out_prepare()),
                         { tmp_, {} },
                         more_input_);
 
@@ -491,8 +484,7 @@ class serializer::impl
                         return rs.ec;
                     }
 
-                    tmp_ = buffers::sans_prefix(
-                        tmp_, rs.in_bytes);
+                    buffers::trim_front(tmp_, rs.in_bytes);
                     out_commit(rs.out_bytes);
 
                     if(rs.out_short)
@@ -527,8 +519,7 @@ class serializer::impl
                     }
 
                     const auto rs = filter_->process(
-                        buffers::mutable_buffer_span(
-                            out_prepare()),
+                        detail::make_span(out_prepare()),
                         in_.data(),
                         more_input_);
 
@@ -560,8 +551,7 @@ class serializer::impl
                     break;
 
                 const auto rs = filter_->process(
-                    buffers::mutable_buffer_span(
-                        out_prepare()),
+                    detail::make_span(out_prepare()),
                     in_.data(),
                     more_input_);
 
@@ -590,15 +580,12 @@ class serializer::impl
         }
 
         prepped_.reset(!is_header_done());
-        const auto cbp = out_.data();
-        if(cbp[0].size() != 0)
-            prepped_.append(cbp[0]);
-        if(cbp[1].size() != 0)
-            prepped_.append(cbp[1]);
-
-        return const_buffers_type(
-            prepped_.begin(),
-            prepped_.size());
+        for(auto const& cb : out_.data())
+        {
+            if(cb.size() != 0)
+                prepped_.append(cb);
+        }
+        return detail::make_span(prepped_);
     }
 
     void
@@ -880,15 +867,15 @@ class serializer::impl
     buffers::mutable_buffer_pair
     out_prepare() noexcept
     {
+        auto mbp = out_.prepare(out_.capacity());
         if(is_chunked_)
         {
-            return buffers::sans_suffix(
-                buffers::sans_prefix(
-                    out_.prepare(out_.capacity()),
-                    chunk_header_len_),
-                crlf_and_final_chunk.size());
+            buffers::trim_front(
+                mbp, chunk_header_len_);
+            buffers::trim_back(
+                mbp, crlf_and_final_chunk.size());
         }
-        return out_.prepare(out_.capacity());
+        return mbp;
     }
 
     void
diff --git a/src/sink.cpp b/src/sink.cpp
index 1883ac79..6627791b 100644
--- a/src/sink.cpp
+++ b/src/sink.cpp
@@ -15,7 +15,8 @@ namespace http_proto {
 auto
 sink::
 on_write(
-    buffers::const_buffer_span bs,
+    bool,
+    boost::span<buffers::const_buffer const> bs,
     bool more) ->
         results
 {
@@ -27,9 +28,9 @@ on_write(
     do
     {
         buffers::const_buffer b(*it++);
-        rv += on_write(b,
-            it != end_ ||
-            more);
+        rv += on_write(
+            b,
+            it != end_ || more);
         if(rv.ec.failed())
             return rv;
     }
diff --git a/src/source.cpp b/src/source.cpp
index 7b535085..e160104d 100644
--- a/src/source.cpp
+++ b/src/source.cpp
@@ -16,7 +16,8 @@ namespace http_proto {
 auto
 source::
 on_read(
-    buffers::mutable_buffer_span bs) ->
+    bool,
+    boost::span<buffers::mutable_buffer const> bs) ->
         results
 {
     results rv;
diff --git a/test/unit/compression.cpp b/test/unit/compression.cpp
index 643e8186..86ae0dc6 100644
--- a/test/unit/compression.cpp
+++ b/test/unit/compression.cpp
@@ -261,7 +261,7 @@ struct zlib_test
 
                 results rs;
                 auto n = buffers::copy(b, body_);
-                body_ = buffers::sans_prefix(body_, n);
+                buffers::trim_front(body_, n);
                 rs.bytes = n;
                 rs.finished = (body_.size() == 0);
                 done_ = rs.finished;
@@ -296,7 +296,7 @@ struct zlib_test
             {
                 auto mbs = stream.prepare();
                 auto n = buffers::copy(mbs, body);
-                body = buffers::sans_prefix(body, n);
+                buffers::trim_front(body, n);
                 stream.commit(n);
                 if(body.size() == 0)
                     stream.close();
@@ -333,8 +333,10 @@ struct zlib_test
             auto buf_size = std::min(body.size() / 23, body.size());
             if(buf_size == 0)
                 buf_size = 1;
-            buf_seq.push_back(buffers::prefix(body, buf_size));
-            body = buffers::sans_prefix(body, buf_size);
+            buf_seq.emplace_back(
+                body.data(),
+                body.size() ? buf_size : 0);
+            buffers::trim_front(body, buf_size);
         } while(body.size() != 0);
 
         sr.start(res, buf_seq);
@@ -481,8 +483,8 @@ struct zlib_test
             if(input.size() != 0)
             {
                 auto n1 = buffers::copy(pr.prepare(), input);
+                buffers::trim_front(input, n1);
                 pr.commit(n1);
-                input = buffers::sans_prefix(input, n1);
             }
 
             boost::system::error_code ec;
@@ -519,9 +521,8 @@ struct zlib_test
         buffers::const_buffer input)
     {
         std::string rs;
-        std::size_t n1 = buffers::copy(
-                pr.prepare(), input);
-        input = buffers::sans_prefix(input, n1);
+        auto n1 = buffers::copy(pr.prepare(), input);
+        buffers::trim_front(input, n1);
         pr.commit(n1);
         system::error_code ec;
         pr.parse(ec);
@@ -533,9 +534,8 @@ struct zlib_test
 
         while(ec == error::need_data)
         {
-            std::size_t n2 = buffers::copy(
-                    pr.prepare(), input);
-            input = buffers::sans_prefix(input, n2);
+            auto n2 = buffers::copy(pr.prepare(), input);
+            buffers::trim_front(input, n2);
             pr.commit(n2);
             pr.parse(ec);
             if(n2 == 0)
@@ -554,9 +554,8 @@ struct zlib_test
         response_parser& pr,
         buffers::const_buffer input)
     {
-        std::size_t n1 = buffers::copy(
-                pr.prepare(), input);
-        input = buffers::sans_prefix(input, n1);
+        auto n1 = buffers::copy(pr.prepare(), input);
+        buffers::trim_front(input, n1);
         pr.commit(n1);
         system::error_code ec;
         pr.parse(ec);
@@ -596,9 +595,8 @@ struct zlib_test
 
         while(ec == error::need_data)
         {
-            std::size_t n2 = buffers::copy(
-                    pr.prepare(), input);
-            input = buffers::sans_prefix(input, n2);
+            auto n2 = buffers::copy(pr.prepare(), input);
+            buffers::trim_front(input, n2);
             pr.commit(n2);
             pr.parse(ec);
             if(n2 == 0)
diff --git a/test/unit/file_source.cpp b/test/unit/file_source.cpp
index ee0b4259..aae19b10 100644
--- a/test/unit/file_source.cpp
+++ b/test/unit/file_source.cpp
@@ -11,7 +11,6 @@
 #include <boost/http_proto/file_source.hpp>
 
 #include <boost/buffers/make_buffer.hpp>
-#include <boost/buffers/prefix.hpp>
 #include <boost/filesystem.hpp>
 #include <fstream>
 
@@ -63,7 +62,7 @@ struct file_source_test
             file_source fsource(std::move(f));
             char buf[16] = {};
             auto rs = fsource.read(
-                buffers::mutable_buffer(buf, 16));
+                buffers::make_buffer(buf));
             BOOST_TEST_EQ(rs.bytes, 0);
             BOOST_TEST(rs.ec.failed());
             BOOST_TEST(!rs.finished);
@@ -86,8 +85,7 @@ struct file_source_test
             core::string_view
         {
             auto rs = fsource.read(
-                buffers::prefix(
-                    buffers::make_buffer(buf), n));
+                buffers::mutable_buffer{ buf, n });
             BOOST_TEST_EQ(rs.finished, !more);
             BOOST_TEST(!rs.ec);
             return { buf, rs.bytes };
@@ -112,7 +110,8 @@ struct file_source_test
 
         {
             char buf[5] = {};
-            auto rs = fsource.read(buffers::make_buffer(buf));
+            auto rs = fsource.read(
+                buffers::make_buffer(buf));
             BOOST_TEST_EQ(rs.bytes, 5);
             BOOST_TEST(!rs.ec);
             BOOST_TEST(!rs.finished);
@@ -123,7 +122,8 @@ struct file_source_test
 
         {
             char buf[5] = {};
-            auto rs = fsource.read(buffers::make_buffer(buf));
+            auto rs = fsource.read(
+                buffers::make_buffer(buf));
             BOOST_TEST_EQ(rs.bytes, 1);
             BOOST_TEST(!rs.ec);
             BOOST_TEST(rs.finished);
diff --git a/test/unit/parser.cpp b/test/unit/parser.cpp
index d1e446d7..55f8ee95 100644
--- a/test/unit/parser.cpp
+++ b/test/unit/parser.cpp
@@ -14,7 +14,6 @@
 #include <boost/http_proto/response_parser.hpp>
 
 #include <boost/buffers/copy.hpp>
-#include <boost/buffers/size.hpp>
 #include <boost/buffers/flat_buffer.hpp>
 #include <boost/buffers/make_buffer.hpp>
 #include <boost/buffers/string_buffer.hpp>
diff --git a/test/unit/serializer.cpp b/test/unit/serializer.cpp
index e7976f37..5c4ad838 100644
--- a/test/unit/serializer.cpp
+++ b/test/unit/serializer.cpp
@@ -12,12 +12,9 @@
 #include <boost/http_proto/serializer.hpp>
 #include <boost/http_proto/response.hpp>
 
-#include <boost/buffers/const_buffer.hpp>
 #include <boost/buffers/copy.hpp>
 #include <boost/buffers/make_buffer.hpp>
-#include <boost/buffers/mutable_buffer.hpp>
-#include <boost/buffers/prefix.hpp>
-#include <boost/buffers/size.hpp>
+#include <boost/buffers/slice.hpp>
 #include <boost/buffers/string_buffer.hpp>
 #include <boost/core/ignore_unused.hpp>
 #include <boost/rts/context.hpp>
@@ -114,14 +111,17 @@ struct serializer_test
     std::string
     read_some(serializer& sr)
     {
-        auto cbs = sr.prepare().value();
+        buffers::slice_of<
+            serializer::const_buffers_type> cbs
+                = sr.prepare().value();
         BOOST_TEST(!sr.is_done());
         // We limit buffer consumption to necessitate
         // multiple calls to serializer::prepare() and
         // serializer::consume(), allowing tests to cover
         // state management within these functions
         std::string s;
-        for( auto buf : buffers::prefix(cbs, 256) )
+        buffers::keep_front(cbs, 256);
+        for( auto buf : cbs)
         {
             s.append(
                 reinterpret_cast<char const*>(buf.data()),
@@ -326,9 +326,7 @@ struct serializer_test
         rts::context ctx;
         install_serializer_service(ctx, {});
         serializer sr(ctx);
-        buffers::const_buffer_span cbs(
-            buf.data(), buf.size());
-        sr.start(res, cbs);
+        sr.start(res, buf);
         std::string s = read(sr);
         core::string_view sv(s);
 
@@ -412,17 +410,15 @@ struct serializer_test
 
             while( buf.size() > 0 )
             {
-                auto num_copied =
-                    buffers::copy(out_buf, buf);
-
-                buf = buffers::sans_prefix(buf, num_copied);
+                auto n = buffers::copy(out_buf, buf);
+                buffers::trim_front(buf, n);
 
                 s.insert(
                     s.end(),
                     storage.begin(),
-                    storage.begin() + num_copied);
+                    storage.begin() + n);
 
-                sr.consume(num_copied);
+                sr.consume(n);
             }
         };
 
diff --git a/test/unit/sink.cpp b/test/unit/sink.cpp
index b0e21f63..44b90863 100644
--- a/test/unit/sink.cpp
+++ b/test/unit/sink.cpp
@@ -69,7 +69,7 @@ struct sink_test
                 { &pat[0], 3 },
                 { &pat[3], 5 },
                 { &pat[8], 7 } };
-            buffers::const_buffer_span bs(cb, 3);
+            boost::span<buffers::const_buffer const> bs(cb);
             auto rv = dest.write(bs, false);
             if(rv.ec.failed())
                 continue;
@@ -107,8 +107,9 @@ struct sink_test
         // empty sequence
         {
             test_sink dest(99);
-            buffers::const_buffer_span bs;
-            auto rv = dest.write(bs, true);
+            auto rv = dest.write(
+                boost::span<buffers::const_buffer const>{},
+                true);
             BOOST_TEST(! rv.ec.failed());
             BOOST_TEST_EQ(rv.bytes, 0);
         }
diff --git a/test/unit/source.cpp b/test/unit/source.cpp
index 449ce7b6..6e781b9c 100644
--- a/test/unit/source.cpp
+++ b/test/unit/source.cpp
@@ -10,6 +10,9 @@
 // Test that header file is self-contained.
 #include <boost/http_proto/source.hpp>
 
+#include <boost/buffers/slice.hpp>
+#include <boost/buffers/range.hpp>
+
 #include "test_helpers.hpp"
 
 namespace boost {
@@ -43,9 +46,8 @@ struct source_test
                     boost::system::generic_category());
                 return rv;
             }
-            auto const n =
-                buffers::copy(b, cb_);
-            cb_ = buffers::sans_prefix(cb_, n);
+            auto n = buffers::copy(b, cb_);
+            buffers::trim_front(cb_, n);
             rv.bytes += n;
             rv.finished = cb_.size() == 0;
             return rv;
@@ -67,7 +69,7 @@ struct source_test
                 { &s[0], 3 },
                 { &s[3], 5 },
                 { &s[8], 7 } };
-            buffers::mutable_buffer_span bs(mb, 3);
+            boost::span<buffers::mutable_buffer const> bs(mb);
             auto rv = src.read(bs);
             if(rv.ec.failed())
                 continue;
@@ -101,8 +103,8 @@ struct source_test
         // empty sequence
         {
             test_source src(99);
-            buffers::mutable_buffer_span bs;
-            auto rv = src.read(bs);
+            auto rv = src.read(
+                boost::span<buffers::mutable_buffer const>{});
             BOOST_TEST(! rv.ec.failed());
             BOOST_TEST_EQ(rv.bytes, 0);
         }
diff --git a/test/unit/test_helpers.hpp b/test/unit/test_helpers.hpp
index c26b9ca5..f7a99618 100644
--- a/test/unit/test_helpers.hpp
+++ b/test/unit/test_helpers.hpp
@@ -14,10 +14,9 @@
 #include <boost/http_proto/request.hpp>
 #include <boost/http_proto/response.hpp>
 #include <boost/buffers/copy.hpp>
-#include <boost/buffers/size.hpp>
 #include <boost/buffers/make_buffer.hpp>
-#include <boost/url/grammar/parse.hpp>
 #include <boost/core/detail/string_view.hpp>
+#include <boost/url/grammar/parse.hpp>
 
 #include "test_suite.hpp"