diff --git a/backend/Makefile b/backend/Makefile
index 44fa4a1..ed14531 100644
--- a/backend/Makefile
+++ b/backend/Makefile
@@ -4,7 +4,7 @@ MAKEFLAGS += -j16
 CXX=g++
 LD=g++
 
-CXXFLAGS = -std=c++23 -pedantic-errors -Wall -Wextra -Wconversion
+CXXFLAGS = -std=c++23 -pedantic-errors -Wall -Wextra -Wconversion -ftemplate-backtrace-limit=0
 LDFLAGS =
 
 libraries = libmosquitto
diff --git a/backend/src/json.cpp_cant_compile b/backend/src/json.cpp
similarity index 89%
rename from backend/src/json.cpp_cant_compile
rename to backend/src/json.cpp
index 8912f47..db699cb 100644
--- a/backend/src/json.cpp_cant_compile
+++ b/backend/src/json.cpp
@@ -131,7 +131,7 @@ private:
     auto make_string_tok(Loc loc, size_t* i) -> Result<Tok>
     {
         step();
-        while (*i < m_len && m_text[*i] != '\"') {
+        while (*i < m_len && m_text[*i] != '\"' && m_text[*i] != '\n') {
             if (m_text[*i] == '\\') {
                 step();
                 if (*i >= m_len)
@@ -139,6 +139,9 @@ private:
             }
             step();
         }
+        if (*i < m_len && m_text[*i] != '\n') [[unlikely]] {
+            return std::unexpected(Error { loc, "malformed string" });
+        }
         if (*i >= m_len && m_text[*i] != '\"') [[unlikely]] {
             return std::unexpected(Error { loc, "malformed string" });
         }
@@ -570,7 +573,7 @@ auto string_to_literal(std::string_view text) -> std::string
 template <typename Writer> void write_indent(Writer& writer, int depth)
 {
     for (int i = 0; i < depth; ++i) {
-        std::format(writer, "  ");
+        writer << "  ";
     }
 }
 
@@ -579,70 +582,70 @@ void write(Writer& writer, const Value& node, int depth = 0)
 {
     switch (node.type()) {
         case Type::Null:
-            std::format(writer, "null");
+            writer << "null";
             break;
         case Type::False:
-            std::format(writer, "false");
+            writer << "false";
             break;
         case Type::True:
-            std::format(writer, "true");
+            writer << "true";
             break;
         case Type::I64:
-            std::format(writer, "{}", node.get_i64());
+            writer << std::format("{}", node.get_i64());
             break;
         case Type::F64:
-            std::format(writer, "{}", node.get_f64());
+            writer << std::format("{}", node.get_f64());
             break;
         case Type::String:
-            std::format(writer, "{}", string_to_literal(node.get_string()));
+            writer << string_to_literal(node.get_string());
             break;
         case Type::Array: {
-            std::format(writer, "[");
+            writer << "[";
             auto first = true;
             for (const auto& child : node.get_underlying_array()) {
                 if (!first) {
-                    std::format(writer, ",");
+                    writer << ",";
                 }
                 first = false;
 
                 if constexpr (profile == WriteProfile::Pretty) {
-                    std::format(writer, "\n");
+                    writer << "\n";
                     write_indent(writer, depth + 1);
                 }
-                write(writer, child, depth + 1);
+                write<Writer, profile>(writer, *child, depth + 1);
             }
             if constexpr (profile == WriteProfile::Pretty) {
-                std::format(writer, "\n");
+                writer << "\n";
                 write_indent(writer, depth);
             }
-            std::format(writer, "]");
+            writer << "]";
             break;
         }
         case Type::Object: {
-            std::format(writer, "{");
+            writer << "{";
             auto first = true;
             for (const auto& [key, child] : node.get_underlying_object()) {
                 if (!first) {
-                    std::format(writer, ",");
+                    writer << ",";
                 }
                 first = false;
 
                 if constexpr (profile == WriteProfile::Pretty) {
-                    std::format(writer, "\n");
+                    writer << "\n";
                     write_indent(writer, depth + 1);
                 }
-                write(writer, string_to_literal(key));
-                write(writer, ":");
+                writer << string_to_literal(key);
+                writer << ":";
                 if constexpr (profile == WriteProfile::Pretty) {
-                    std::format(writer, " ");
+                    writer << " ";
                 }
-                write(writer, child, depth + 1);
+                write<Writer, profile>(writer, *child, depth + 1);
             }
             if constexpr (profile == WriteProfile::Pretty) {
-                std::format(writer, "\n");
+                writer << "\n";
                 write_indent(writer, depth);
             }
-            std::format(writer, "}");
+            writer << "}";
             break;
         }
     }
@@ -652,6 +655,40 @@ void write(Writer& writer, const Value& node, int depth = 0)
 
 namespace mst::json {
 
+auto Value::clone() const -> std::unique_ptr<Value>
+{
+    switch (type()) {
+        case Type::Null:
+            return make_null();
+        case Type::False:
+            return make_bool(false);
+        case Type::True:
+            return make_bool(true);
+        case Type::I64:
+            return make_i64(get_i64());
+        case Type::F64:
+            return make_f64(get_f64());
+        case Type::String:
+            return make_string(get_string());
+        case Type::Array: {
+            auto array = Array();
+            for (const auto& val : get_underlying_array()) {
+                array.push_back(val->clone());
+            }
+            return std::make_unique<Value>(Type::Array, Data(std::move(array)));
+        }
+        case Type::Object: {
+            auto object = Object();
+            for (const auto& [key, val] : get_underlying_object()) {
+                object[key] = val->clone();
+            }
+            return std::make_unique<Value>(
+                Type::Object, Data(std::move(object)));
+        }
+    }
+    std::unreachable();
+}
+
 auto Value::query(std::string_view path) & -> Result<Value*, std::string>
 {
     auto parser = query::Parser(path);
@@ -665,15 +702,6 @@ auto Value::query(
     return query::resolve(parser, *this);
 }
 
-auto Value::write(std::FILE* file, WriteProfile profile) const
-{
-    if (profile == WriteProfile::Minified) {
-        stringify::write<std::FILE*, WriteProfile::Minified>(file, *this);
-    } else {
-        stringify::write<std::FILE*, WriteProfile::Pretty>(file, *this);
-    }
-}
-
 auto Value::write(std::ostream& stream, WriteProfile profile) const
 {
     if (profile == WriteProfile::Minified) {
diff --git a/backend/src/json.hpp b/backend/src/json.hpp
index 116cc0a..6e1013b 100644
--- a/backend/src/json.hpp
+++ b/backend/src/json.hpp
@@ -58,35 +58,6 @@ public:
     Value& operator=(const Value&) = delete;
     Value& operator=(Value&&) = delete;
 
-    static auto make_null() -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(Type::Null);
-    }
-    static auto make_bool(bool value) -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(value ? Type::True : Type::False);
-    }
-    static auto make_i64(I64 value) -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(Type::I64, value);
-    }
-    static auto make_f64(F64 value) -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(Type::F64, value);
-    }
-    static auto make_string(std::string value) -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(Type::String, std::move(value));
-    }
-    static auto make_array() -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(Type::Array, Array());
-    }
-    static auto make_object() -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(Type::Object, Object());
-    }
-
     explicit Value(Type type)
         : m_type(std::move(type))
         , m_data(std::monostate())
@@ -99,6 +70,35 @@ public:
     {
     }
 
+    static auto make_null() -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(Type::Null);
+    }
+    static auto make_bool(bool value) -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(value ? Type::True : Type::False);
+    }
+    static auto make_i64(I64 value) -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(Type::I64, Data(value));
+    }
+    static auto make_f64(F64 value) -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(Type::F64, Data(value));
+    }
+    static auto make_string(std::string value) -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(Type::String, Data(std::move(value)));
+    }
+    static auto make_array() -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(Type::Array, Data(Array()));
+    }
+    static auto make_object() -> std::unique_ptr<Value>
+    {
+        return std::make_unique<Value>(Type::Object, Data(Object()));
+    }
+
     inline auto type() const -> Type
     {
         return m_type;
@@ -191,11 +191,6 @@ public:
         return get_underlying_object().contains(key);
     }
 
-    inline auto clone() const -> std::unique_ptr<Value>
-    {
-        return std::make_unique<Value>(m_type, Data(m_data));
-    }
-
     inline auto push(std::unique_ptr<Value> value)
     {
         get_underlying_array().push_back(std::move(value));
@@ -264,12 +259,12 @@ public:
         m_data = Object();
     }
 
+    auto clone() const -> std::unique_ptr<Value>;
+
     auto query(std::string_view path) & -> Result<Value*, std::string>;
     auto query(
         std::string_view path) const& -> Result<const Value*, std::string>;
 
-    auto write(
-        std::FILE* file, WriteProfile profile = WriteProfile::Minified) const;
     auto write(std::ostream& stream,
         WriteProfile profile = WriteProfile::Minified) const;
     auto to_string(WriteProfile profile = WriteProfile::Minified)
diff --git a/backend/src/main.cpp b/backend/src/main.cpp
index 1e501a7..446968e 100644
--- a/backend/src/main.cpp
+++ b/backend/src/main.cpp
@@ -1,4 +1,5 @@
 #include "event_loop.hpp"
+#include "json.hpp"
 #include "mqtt.hpp"
 #include "server.hpp"
 #include <chrono>
@@ -12,15 +13,28 @@
 #include <sys/types.h>
 #include <thread>
 
+#ifdef BACKEND_TCP_PORT
+#define PORT BACKEND_TCP_PORT
+#else
 #define PORT 8888
+#endif
+
+#ifndef BACKEND_MQTT_PORT
+#define BACKEND_MQTT_PORT 1883
+#endif
 
 int main(void)
 {
-    auto mqtt_client = mst::mqtt::Client("localhost", 1883, "test", "1234");
+    auto mqtt_client
+        = mst::mqtt::Client("localhost", BACKEND_MQTT_PORT, "test", "1234");
 
     mqtt_client.subscribe("/skateboard/update", [&](std::string_view text) {
         //
         std::println("Skateboard: {}", text);
+        auto parsed = mst::json::parse(text).value();
+
+        std::println(".acceleration[0]",
+            parsed->query(".acceleration[0]").value()->get_i64());
     });
 
     auto mqtt_thread = std::thread([&]() {