diff --git a/include/snipplib/utils/snplib_keyvalue.h b/include/snipplib/utils/snplib_keyvalue.h
new file mode 100644
index 0000000..fed9b8c
--- /dev/null
+++ b/include/snipplib/utils/snplib_keyvalue.h
@@ -0,0 +1,80 @@
+#pragma once
+
+#include "../concepts/snplib_concepts.h"
+#include "../serialization/snplib_serialization.h"
+
+namespace snplib
+{
+
+template <typename T>
+concept snplib_serializable_c =
+    requires { []<typename VT>(std::type_identity<VT>) {}(std::type_identity<std::remove_cvref_t<T>>{}); };
+
+template <snplib_char_range_c ByteSeqT>
+class snplib_keyvalue_t
+{
+public:
+    static constexpr bool mutableContent = snplib_output_char_range_c<ByteSeqT>;
+
+    typedef std::error_code error_t;
+
+    static constexpr std::string_view DEFAULT_KEYVALUE_DELIM_SEQ{" "};
+    static constexpr std::string_view DEFAULT_VALSEQ_DELIM_SEQ{" "};
+
+    struct config_t {
+        std::string_view keyval_delim{DEFAULT_KEYVALUE_DELIM_SEQ};
+        std::string_view valseq_delim{DEFAULT_VALSEQ_DELIM_SEQ};
+    };
+
+    constexpr snplib_keyvalue_t(ByteSeqT&& bytes, config_t cfg = config_t{}) {}
+
+    virtual ~snplib_keyvalue_t() = default;
+
+    template <snplib_char_range_c R>
+        requires mutableContent
+    error_t fromByteSequence(R&& r)
+    {
+    }
+
+    template <snplib_char_range_c R>
+    constexpr R key() const
+    {
+        return snplib_transform_char_range<R>(_key);
+    }
+
+    constexpr std::string_view key() const
+    {
+        return key<std::string_view>();
+    }
+
+    template <snplib_char_range_c R>
+    constexpr R value() const
+    {
+        return snplib_transform_char_range<R>(_value);
+    }
+
+    constexpr std::string_view value() const
+    {
+        return value<std ::string_view>();
+    }
+
+
+    template <snplib_serializable_c KeyT, snplib_serialization_params_c SParT = snplib_serialization_params_t>
+        requires mutableContent
+    error_t setKey(KeyT&& key, SParT const& sparams = snplib_serialization_params_t{})
+    {
+        auto err = snplib_serializer_t<std::remove_cvref_t<KeyT>>(_key, std::forward<KeyT>(key), sparams);
+        if (err) {
+            return snplib_deduced_error(err, std::errc::invalid_argument);
+        }
+
+        return {};
+    }
+
+protected:
+    std::conditional_t<mutableContent, std::string, std::string_view> _key;
+    std::conditional_t<mutableContent, std::string, std::string_view> _value;
+    std::conditional_t<mutableContent, std::vector<std::string>, std::vector<std::string_view>> _valueSeq;
+};
+
+}  // namespace snplib
\ No newline at end of file
diff --git a/include/snipplib/utils/snplib_string.h b/include/snipplib/utils/snplib_string.h
index 78ae587..4063878 100644
--- a/include/snipplib/utils/snplib_string.h
+++ b/include/snipplib/utils/snplib_string.h
@@ -81,7 +81,7 @@ constexpr static std::string_view snplib_trim_spaces_as_view(R&& r,
 
 
 template <snplib_input_char_range_c R1, snplib_input_char_range_c R2>
-bool snplib_char_ranges_compare(R1&& what, R2&& where, bool case_insensitive = false)
+static constexpr bool snplib_char_ranges_compare(R1&& what, R2&& where, bool case_insensitive = false)
 {
     auto sz1 = std::ranges::distance(what.begin(), what.end()), sz2 = std::ranges::distance(where.begin(), where.end());
 
@@ -105,6 +105,22 @@ bool snplib_char_ranges_compare(R1&& what, R2&& where, bool case_insensitive = f
 }
 
 
+template <snplib_char_range_c OR, snplib_char_range_c IR, typename... CTorTs>
+static constexpr OR snplib_transform_char_range(IR&& r, CTorTs&&... or_ctor_args)
+{
+    using val_t = std::remove_cvref_t<IR>;
+
+    if constexpr (std::same_as<OR, val_t>) {  // just a copy
+        return r;
+    } else if constexpr (snplib_char_view_c<OR> && std::ranges::viewable_range<val_t>) {
+        return OR{r.begin(), r.end()};
+    } else if (snplib_output_char_range_c<OR>) {
+        OR res(std::forward<CTorTs>(or_ctor_args)...);
+        std::ranges::copy(std::forward<IR>(r), std::back_inserter(res));
+    } else {
+        static_assert(false, "Incompatible types!");
+    }
+}
 
 template <typename T, snplib_input_char_range_c R>
 static std::optional<T> snplib_num_from_range(R&& r)