diff --git a/src/ALabel.cpp b/src/ALabel.cpp
index 2d1ea5e8..00b37d74 100644
--- a/src/ALabel.cpp
+++ b/src/ALabel.cpp
@@ -4,15 +4,15 @@
 
 waybar::ALabel::ALabel(const Json::Value& config, const std::string format)
   : config_(config),
-    format_(config_["format"] ? config_["format"].asString() : format),
+    format_(config_["format"].isString() ? config_["format"].asString() : format),
     default_format_(format_)
 {
   event_box_.add(label_);
-	if (config_["max-length"]) {
+	if (config_["max-length"].isUInt()) {
     label_.set_max_width_chars(config_["max-length"].asUInt());
     label_.set_ellipsize(Pango::EllipsizeMode::ELLIPSIZE_END);
   }
-  if (config_["format-alt"]) {
+  if (config_["format-alt"].isString()) {
     event_box_.add_events(Gdk::BUTTON_PRESS_MASK);
     event_box_.signal_button_press_event()
       .connect(sigc::mem_fun(*this, &ALabel::handleToggle));
diff --git a/src/bar.cpp b/src/bar.cpp
index 2097a35d..24ef1f01 100644
--- a/src/bar.cpp
+++ b/src/bar.cpp
@@ -53,8 +53,8 @@ waybar::Bar::Bar(const Client& client,
     anchor |= ZWLR_LAYER_SURFACE_V1_ANCHOR_TOP;
   }
 
-  auto height = config_["height"] ? config_["height"].asUInt() : height_;
-  auto width = config_["width"] ? config_["width"].asUInt() : width_;
+  auto height = config_["height"].isUInt() ? config_["height"].asUInt() : height_;
+  auto width = config_["width"].isUInt() ? config_["width"].asUInt() : width_;
   zwlr_layer_surface_v1_set_anchor(layer_surface, anchor);
   zwlr_layer_surface_v1_set_exclusive_zone(layer_surface, height);
   zwlr_layer_surface_v1_set_size(layer_surface, width, height);
@@ -163,7 +163,7 @@ auto waybar::Bar::setupCss() -> void
 
 void waybar::Bar::getModules(const Factory& factory, const std::string& pos)
 {
-  if (config_[pos]) {
+  if (config_[pos].isArray()) {
     for (const auto &name : config_[pos]) {
       try {
         auto module = factory.makeModule(name.asString());
diff --git a/src/modules/battery.cpp b/src/modules/battery.cpp
index 53abbe59..569ffbed 100644
--- a/src/modules/battery.cpp
+++ b/src/modules/battery.cpp
@@ -4,7 +4,7 @@ waybar::modules::Battery::Battery(const Json::Value& config)
   : ALabel(config, "{capacity}%")
 {
   try {
-    if (config_["bat"]) {
+    if (config_["bat"].isString()) {
       auto dir = data_dir_ / config_["bat"].asString();
       if (fs::is_directory(dir) && fs::exists(dir / "capacity")
         && fs::exists(dir / "status") && fs::exists(dir / "uevent")) {
@@ -22,7 +22,7 @@ waybar::modules::Battery::Battery(const Json::Value& config)
     throw std::runtime_error(e.what());
   }
   if (batteries_.empty()) {
-    if (config_["bat"]) {
+    if (config_["bat"].isString()) {
       throw std::runtime_error("No battery named " + config_["bat"].asString());
     }
     throw std::runtime_error("No batteries.");
@@ -47,7 +47,7 @@ void waybar::modules::Battery::worker()
 {
   // Trigger first values
   update();
-  uint32_t interval = config_["interval"] ? config_["interval"].asUInt() : 60;
+  uint32_t interval = config_["interval"].isUInt() ? config_["interval"].asUInt() : 60;
   threadTimer_ = [this, interval] {
     thread_.sleep_for(chrono::seconds(interval));
     dp.emit();
@@ -88,7 +88,7 @@ auto waybar::modules::Battery::update() -> void
     } else {
       label_.get_style_context()->remove_class("charging");
     }
-    auto critical = config_["critical"] ? config_["critical"].asUInt() : 15;
+    auto critical = config_["critical"].isUInt() ? config_["critical"].asUInt() : 15;
     if (capacity <= critical && !charging) {
       label_.get_style_context()->add_class("warning");
     } else {
diff --git a/src/modules/clock.cpp b/src/modules/clock.cpp
index 154041ae..af9dadb3 100644
--- a/src/modules/clock.cpp
+++ b/src/modules/clock.cpp
@@ -4,7 +4,7 @@ waybar::modules::Clock::Clock(const Json::Value& config)
   : ALabel(config, "{:%H:%M}")
 {
   label_.set_name("clock");
-  uint32_t interval = config_["interval"] ? config_["interval"].asUInt() : 60;
+  uint32_t interval = config_["interval"].isUInt() ? config_["interval"].asUInt() : 60;
   thread_ = [this, interval] {
     auto now = waybar::chrono::clock::now();
     dp.emit();
diff --git a/src/modules/cpu.cpp b/src/modules/cpu.cpp
index 3aa1fd5f..5bb836ea 100644
--- a/src/modules/cpu.cpp
+++ b/src/modules/cpu.cpp
@@ -4,7 +4,7 @@ waybar::modules::Cpu::Cpu(const Json::Value& config)
   : ALabel(config, "{}%")
 {
   label_.set_name("cpu");
-  uint32_t interval = config_["interval"] ? config_["interval"].asUInt() : 10;
+  uint32_t interval = config_["interval"].isUInt() ? config_["interval"].asUInt() : 10;
   thread_ = [this, interval] {
     dp.emit();
     thread_.sleep_for(chrono::seconds(interval));
diff --git a/src/modules/custom.cpp b/src/modules/custom.cpp
index 347f51c1..5a38e35d 100644
--- a/src/modules/custom.cpp
+++ b/src/modules/custom.cpp
@@ -4,10 +4,10 @@ waybar::modules::Custom::Custom(const std::string name,
   const Json::Value& config)
   : ALabel(config, "{}"), name_(name)
 {
-  if (!config_["exec"]) {
+  if (!config_["exec"].isString()) {
     throw std::runtime_error(name_ + " has no exec path.");
   }
-  if (config_["interval"]) {
+  if (config_["interval"].isUInt()) {
     delayWorker();
   } else {
     continuousWorker();
@@ -19,7 +19,7 @@ void waybar::modules::Custom::delayWorker()
   auto interval = config_["interval"].asUInt();
   thread_ = [this, interval] {
     bool can_update = true;
-    if (config_["exec-if"]) {
+    if (config_["exec-if"].isString()) {
       auto res = waybar::util::command::exec(config_["exec-if"].asString());
       if (res.exit_code != 0) {
         can_update = false;
diff --git a/src/modules/memory.cpp b/src/modules/memory.cpp
index 630e6428..b2093e8e 100644
--- a/src/modules/memory.cpp
+++ b/src/modules/memory.cpp
@@ -4,7 +4,7 @@ waybar::modules::Memory::Memory(const Json::Value& config)
   : ALabel(config, "{}%")
 {
   label_.set_name("memory");
-  uint32_t interval = config_["interval"] ? config_["interval"].asUInt() : 30;
+  uint32_t interval = config_["interval"].isUInt() ? config_["interval"].asUInt() : 30;
   thread_ = [this, interval] {
     dp.emit();
     thread_.sleep_for(chrono::seconds(interval));
diff --git a/src/modules/network.cpp b/src/modules/network.cpp
index 1df835e9..e57e44aa 100644
--- a/src/modules/network.cpp
+++ b/src/modules/network.cpp
@@ -14,7 +14,7 @@ waybar::modules::Network::Network(const Json::Value& config)
     sizeof(nladdr_)) != 0) {
     throw std::runtime_error("Can't bind network socket");
   }
-  if (config_["interface"]) {
+  if (config_["interface"].isString()) {
     ifid_ = if_nametoindex(config_["interface"].asCString());
     ifname_ = config_["interface"].asString();
     if (ifid_ <= 0) {
@@ -56,7 +56,7 @@ waybar::modules::Network::Network(const Json::Value& config)
         }
       }
     }
-    if (ifid_ <= 0 && !config_["interface"]) {
+    if (ifid_ <= 0 && !config_["interface"].isString()) {
       // Need to wait before get external interface
       thread_.sleep_for(std::chrono::seconds(1));
       ifid_ = getExternalInterface();
@@ -84,15 +84,15 @@ auto waybar::modules::Network::update() -> void
 {
   auto format = format_;
   if (ifid_ <= 0) {
-    format = config_["format-disconnected"]
+    format = config_["format-disconnected"].isString()
       ? config_["format-disconnected"].asString() : format;
     label_.get_style_context()->add_class("disconnected");
   } else {
     if (essid_.empty()) {
-      format = config_["format-ethernet"]
+      format = config_["format-ethernet"].isString()
         ? config_["format-ethernet"].asString() : format;
     } else {
-      format = config_["format-wifi"]
+      format = config_["format-wifi"].isString()
         ? config_["format-wifi"].asString() : format;
     }
     label_.get_style_context()->remove_class("disconnected");
diff --git a/src/modules/pulseaudio.cpp b/src/modules/pulseaudio.cpp
index fb5b6f2b..7f6d2970 100644
--- a/src/modules/pulseaudio.cpp
+++ b/src/modules/pulseaudio.cpp
@@ -131,10 +131,10 @@ auto waybar::modules::Pulseaudio::update() -> void
   auto format = format_;
   if (muted_) {
     format =
-      config_["format-muted"] ? config_["format-muted"].asString() : format;
+      config_["format-muted"].isString() ? config_["format-muted"].asString() : format;
     label_.get_style_context()->add_class("muted");
   } else if (port_name_.find("a2dp_sink") != std::string::npos) {
-    format = config_["format-bluetooth"]
+    format = config_["format-bluetooth"].isString()
       ? config_["format-bluetooth"].asString() : format;
     label_.get_style_context()->add_class("bluetooth");
   } else {
diff --git a/src/modules/sway/workspaces.cpp b/src/modules/sway/workspaces.cpp
index 63166378..af8e5c46 100644
--- a/src/modules/sway/workspaces.cpp
+++ b/src/modules/sway/workspaces.cpp
@@ -79,7 +79,7 @@ auto waybar::modules::sway::Workspaces::update() -> void
         box_.reorder_child(button, node["num"].asInt());
       }
       auto icon = getIcon(node["name"].asString(), node);
-      if (config_["format"]) {
+      if (config_["format"].isString()) {
         auto format = config_["format"].asString();
         button.set_label(fmt::format(format, fmt::arg("icon", icon),
           fmt::arg("name", node["name"].asString()),
@@ -98,7 +98,7 @@ auto waybar::modules::sway::Workspaces::update() -> void
 void waybar::modules::sway::Workspaces::addWorkspace(Json::Value node)
 {
   auto icon = getIcon(node["name"].asString(), node);
-  auto format = config_["format"]
+  auto format = config_["format"].isString()
     ? fmt::format(config_["format"].asString(), fmt::arg("icon", icon),
       fmt::arg("name", node["name"].asString()),
       fmt::arg("index", node["num"].asString()))
@@ -141,10 +141,10 @@ std::string waybar::modules::sway::Workspaces::getIcon(std::string name,
     name, "urgent", "focused", "visible", "default"};
   for (auto const& key : keys) {
     if (key == "focused" || key == "visible" || key == "urgent") {
-      if (config_["format-icons"][key] && node[key].asBool()) {
+      if (config_["format-icons"][key].isString() && node[key].asBool()) {
         return config_["format-icons"][key].asString();
       }
-    } else if (config_["format-icons"][key]) {
+    } else if (config_["format-icons"][key].isString()) {
       return config_["format-icons"][key].asString();
     }
   }