diff --git a/src/sensesp.h b/src/sensesp.h
index c75e93346..868e72538 100644
--- a/src/sensesp.h
+++ b/src/sensesp.h
@@ -12,7 +12,7 @@
 
 #ifndef CORE_DEBUG_LEVEL
 #error \
-    "SensESP v3 requires CORE_DEBUG_LEVEL to be defined. See https://signalk.org/SensESP/pages/migration/."
+    "SensESP v3 requires CORE_DEBUG_LEVEL to be defined. See https:\/\/signalk.org/SensESP/pages/migration/."
 #endif
 
 namespace sensesp {
diff --git a/src/sensesp/net/http_server.h b/src/sensesp/net/http_server.h
index 214fca24b..8ce0d5cc8 100644
--- a/src/sensesp/net/http_server.h
+++ b/src/sensesp/net/http_server.h
@@ -132,13 +132,13 @@ class HTTPServer : public Configurable {
   }
 
   virtual bool set_configuration(const JsonObject& config) override {
-    if (config.containsKey("auth_required")) {
+    if (config["auth_required"].is<bool>()) {
       auth_required_ = config["auth_required"];
     }
-    if (config.containsKey("username")) {
+    if (config["username"].is<String>()) {
       username_ = config["username"].as<String>();
     }
-    if (config.containsKey("password")) {
+    if (config["password"].is<String>()) {
       password_ = config["password"].as<String>();
     }
     return true;
diff --git a/src/sensesp/net/networking.cpp b/src/sensesp/net/networking.cpp
index 6f088a18f..34ae4b08f 100644
--- a/src/sensesp/net/networking.cpp
+++ b/src/sensesp/net/networking.cpp
@@ -218,16 +218,16 @@ void Networking::get_configuration(JsonObject& root) {
 }
 
 bool Networking::set_configuration(const JsonObject& config) {
-  if (config.containsKey("hostname")) {
+  if (config["hostname"].is<String>()) {
     // deal with the legacy Json format
     String hostname = config["hostname"].as<String>();
     SensESPBaseApp::get()->get_hostname_observable()->set(hostname);
 
-    if (config.containsKey("ssid")) {
+    if (config["ssid"].is<String>()) {
       String ssid = config["ssid"].as<String>();
       String password = config["password"].as<String>();
 
-      if (config.containsKey("ap_mode")) {
+      if (config["ap_mode"].is<String>()) {
         bool ap_mode;
         if (config["ap_mode"].as<String>() == "Access Point" ||
             config["ap_mode"].as<String>() == "Hotspot") {
@@ -242,12 +242,12 @@ bool Networking::set_configuration(const JsonObject& config) {
     }
   } else {
     // Either an empty config or a new-style config
-    if (config.containsKey("apSettings")) {
+    if (config["apSettings"].is<JsonVariant>()) {
       ap_settings_ = AccessPointSettings::from_json(config["apSettings"]);
     } else {
       ap_settings_ = AccessPointSettings(true);
     }
-    if (config.containsKey("clientSettings")) {
+    if (config["clientSettings"].is<JsonVariant>()) {
       const JsonObject& client_settings_json = config["clientSettings"];
       client_enabled_ = client_settings_json["enabled"] | false;
       client_settings_.clear();
diff --git a/src/sensesp/sensors/analog_input.cpp b/src/sensesp/sensors/analog_input.cpp
index c416aeb19..780f8b976 100644
--- a/src/sensesp/sensors/analog_input.cpp
+++ b/src/sensesp/sensors/analog_input.cpp
@@ -40,7 +40,7 @@ String AnalogInput::get_config_schema() { return kSchema; }
 bool AnalogInput::set_configuration(const JsonObject& config) {
   String const expected[] = {"read_delay"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/sensors/constant_sensor.h b/src/sensesp/sensors/constant_sensor.h
index 8dc4a0ce3..8940d9a96 100644
--- a/src/sensesp/sensors/constant_sensor.h
+++ b/src/sensesp/sensors/constant_sensor.h
@@ -73,7 +73,7 @@ class ConstantSensor : public Sensor<T> {
   }
   virtual bool set_configuration(const JsonObject &config) override {
     // Neither of the configuration parameters are mandatory
-    if (config.containsKey("value")) {
+    if (config["value"].is<T>()) {
       value_ = config["value"].as<T>();
     }
     return true;
diff --git a/src/sensesp/sensors/digital_input.cpp b/src/sensesp/sensors/digital_input.cpp
index ac64c6b64..b1250ef06 100644
--- a/src/sensesp/sensors/digital_input.cpp
+++ b/src/sensesp/sensors/digital_input.cpp
@@ -23,7 +23,7 @@ String DigitalInputState::get_config_schema() { return kSchema2; }
 bool DigitalInputState::set_configuration(const JsonObject& config) {
   String const expected[] = {"read_delay"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
@@ -47,7 +47,7 @@ String DigitalInputCounter::get_config_schema() { return kSchema; }
 bool DigitalInputCounter::set_configuration(const JsonObject& config) {
   String const expected[] = {"read_delay"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
@@ -82,7 +82,7 @@ String DigitalInputDebounceCounter::get_config_schema() {
 bool DigitalInputDebounceCounter::set_configuration(const JsonObject& config) {
   String const expected[] = {"read_delay", "ignore_interval"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       ESP_LOGE(
           __FILENAME__,
           "Cannot set DigitalInputDebounceConfiguration configuration: missing "
diff --git a/src/sensesp/signalk/signalk_listener.cpp b/src/sensesp/signalk/signalk_listener.cpp
index 53d085d64..2a50c1bb3 100644
--- a/src/sensesp/signalk/signalk_listener.cpp
+++ b/src/sensesp/signalk/signalk_listener.cpp
@@ -30,7 +30,7 @@ void SKListener::get_configuration(JsonObject &root) {
 }
 
 bool SKListener::set_configuration(const JsonObject &config) {
-  if (!config.containsKey("sk_path")) {
+  if (!config["sk_path"].is<String>()) {
     return false;
   }
   this->set_sk_path(config["sk_path"].as<String>());
diff --git a/src/sensesp/signalk/signalk_output.h b/src/sensesp/signalk/signalk_output.h
index 247705deb..ed7ad2536 100644
--- a/src/sensesp/signalk/signalk_output.h
+++ b/src/sensesp/signalk/signalk_output.h
@@ -58,7 +58,7 @@ class SKOutput : public SKEmitter, public SymmetricTransform<T> {
   String get_config_schema() override { return FPSTR(SIGNALKOUTPUT_SCHEMA); }
 
   virtual bool set_configuration(const JsonObject& config) override {
-    if (!config.containsKey("sk_path")) {
+    if (!config["sk_path"].is<String>()) {
       return false;
     }
     this->set_sk_path(config["sk_path"].as<String>());
diff --git a/src/sensesp/signalk/signalk_put_request.cpp b/src/sensesp/signalk/signalk_put_request.cpp
index 2174e6a7d..cb227878e 100644
--- a/src/sensesp/signalk/signalk_put_request.cpp
+++ b/src/sensesp/signalk/signalk_put_request.cpp
@@ -135,7 +135,7 @@ String SKPutRequestBase::get_config_schema() { return kSchema; }
 bool SKPutRequestBase::set_configuration(const JsonObject& config) {
   const String expected[] = {"sk_path"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/signalk/signalk_time.cpp b/src/sensesp/signalk/signalk_time.cpp
index cbfda878f..c70479259 100644
--- a/src/sensesp/signalk/signalk_time.cpp
+++ b/src/sensesp/signalk/signalk_time.cpp
@@ -30,7 +30,7 @@ String SKOutputTime::get_config_schema() { return kSchema; }
 bool SKOutputTime::set_configuration(const JsonObject& config) {
   const String expected[] = {"sk_path"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/signalk/signalk_ws_client.cpp b/src/sensesp/signalk/signalk_ws_client.cpp
index 948d126fe..bf1e4566c 100644
--- a/src/sensesp/signalk/signalk_ws_client.cpp
+++ b/src/sensesp/signalk/signalk_ws_client.cpp
@@ -224,16 +224,16 @@ void SKWSClient::on_receive_delta(uint8_t* payload, size_t length) {
   auto error = deserializeJson(message, buf);
 
   if (!error) {
-    if (message.containsKey("updates")) {
+    if (message["updates"].is<JsonVariant>()) {
       on_receive_updates(message);
     }
 
-    if (message.containsKey("put")) {
+    if (message["put"].is<JsonVariant>()) {
       on_receive_put(message);
     }
 
     // Putrequest contains also requestId Key  GA
-    if (message.containsKey("requestId") && !message.containsKey("put")) {
+    if (message["requestId"].is<JsonVariant>() && !message["put"].is<JsonVariant>()) {
       SKRequest::handle_response(message);
     }
   } else {
@@ -696,22 +696,22 @@ void SKWSClient::get_configuration(JsonObject& root) {
 }
 
 bool SKWSClient::set_configuration(const JsonObject& config) {
-  if (config.containsKey("sk_address")) {
+  if (config["sk_address"].is<String>()) {
     this->conf_server_address_ = config["sk_address"].as<String>();
   }
-  if (config.containsKey("sk_port")) {
+  if (config["sk_port"].is<int>()) {
     this->conf_server_port_ = config["sk_port"].as<int>();
   }
-  if (config.containsKey("use_mdns")) {
+  if (config["use_mdns"].is<bool>()) {
     this->use_mdns_ = config["use_mdns"].as<bool>();
   }
-  if (config.containsKey("token")) {
+  if (config["token"].is<String>()) {
     this->auth_token_ = config["token"].as<String>();
   }
-  if (config.containsKey("client_id")) {
+  if (config["client_id"].is<String>()) {
     this->client_id_ = config["client_id"].as<String>();
   }
-  if (config.containsKey("polling_href")) {
+  if (config["polling_href"].is<String>()) {
     this->polling_href_ = config["polling_href"].as<String>();
   }
 
diff --git a/src/sensesp/system/observablevalue.h b/src/sensesp/system/observablevalue.h
index ddf238dee..5c8df832f 100644
--- a/src/sensesp/system/observablevalue.h
+++ b/src/sensesp/system/observablevalue.h
@@ -76,7 +76,7 @@ class PersistingObservableValue : public ObservableValue<T>,
   }
 
   virtual bool set_configuration(const JsonObject& config) override {
-    if (!config.containsKey("value")) {
+    if (!config["value"].is<T>()) {
       return false;
     }
     ObservableValue<T>::set(config["value"]);
diff --git a/src/sensesp/system/rgb_led.cpp b/src/sensesp/system/rgb_led.cpp
index 6bbc020d4..873c117d7 100644
--- a/src/sensesp/system/rgb_led.cpp
+++ b/src/sensesp/system/rgb_led.cpp
@@ -76,7 +76,7 @@ String RgbLed::get_config_schema() { return kSchema; }
 bool RgbLed::set_configuration(const JsonObject& config) {
   String expected[] = {"led_on_rgb", "led_off_rgb"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/analogvoltage.cpp b/src/sensesp/transforms/analogvoltage.cpp
index bab858191..c5167a24a 100644
--- a/src/sensesp/transforms/analogvoltage.cpp
+++ b/src/sensesp/transforms/analogvoltage.cpp
@@ -36,7 +36,7 @@ String AnalogVoltage::get_config_schema() { return kSchema; }
 bool AnalogVoltage::set_configuration(const JsonObject& config) {
   const String expected[] = {"max_voltage", "multiplier", "offset"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/angle_correction.cpp b/src/sensesp/transforms/angle_correction.cpp
index 875b21c91..1f8594bf6 100644
--- a/src/sensesp/transforms/angle_correction.cpp
+++ b/src/sensesp/transforms/angle_correction.cpp
@@ -40,7 +40,7 @@ String AngleCorrection::get_config_schema() { return kSchema; }
 bool AngleCorrection::set_configuration(const JsonObject& config) {
   String const expected[] = {"offset", "min_angle"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/change_filter.cpp b/src/sensesp/transforms/change_filter.cpp
index 030a1049d..1ca97c5e0 100644
--- a/src/sensesp/transforms/change_filter.cpp
+++ b/src/sensesp/transforms/change_filter.cpp
@@ -49,7 +49,7 @@ String ChangeFilter::get_config_schema() { return (kSchema); }
 bool ChangeFilter::set_configuration(const JsonObject& config) {
   String const expected[] = {"min_delta", "max_delta", "max_skips"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/click_type.cpp b/src/sensesp/transforms/click_type.cpp
index ac57bc5cf..21a12ad5b 100644
--- a/src/sensesp/transforms/click_type.cpp
+++ b/src/sensesp/transforms/click_type.cpp
@@ -171,7 +171,7 @@ bool ClickType::set_configuration(const JsonObject& config) {
   String const expected[] = {"long_click_delay", "ultra_long_click_delay",
                              "double_click_interval"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/curveinterpolator.cpp b/src/sensesp/transforms/curveinterpolator.cpp
index 79e7134dc..95aeb3d41 100644
--- a/src/sensesp/transforms/curveinterpolator.cpp
+++ b/src/sensesp/transforms/curveinterpolator.cpp
@@ -136,7 +136,7 @@ String CurveInterpolator::get_config_schema() {
 bool CurveInterpolator::set_configuration(const JsonObject& config) {
   String const expected[] = {"samples"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       ESP_LOGE(
           __FILENAME__,
           "Can not set CurveInterpolator configuration: missing json field "
diff --git a/src/sensesp/transforms/debounce.h b/src/sensesp/transforms/debounce.h
index 8df3aec23..4da87a67f 100644
--- a/src/sensesp/transforms/debounce.h
+++ b/src/sensesp/transforms/debounce.h
@@ -75,7 +75,7 @@ class Debounce : public SymmetricTransform<T> {
   virtual bool set_configuration(const JsonObject& config) override {
     const String expected[] = {"min_delay"};
     for (auto str : expected) {
-      if (!config.containsKey(str)) {
+      if (!config[str].is<JsonVariant>()) {
         return false;
       }
     }
diff --git a/src/sensesp/transforms/enable.h b/src/sensesp/transforms/enable.h
index 7f905e245..561e309a1 100644
--- a/src/sensesp/transforms/enable.h
+++ b/src/sensesp/transforms/enable.h
@@ -38,7 +38,7 @@ class Enable : public Transform<T, T> {
     doc["enabled"] = enabled_;
   }
   virtual bool set_configuration(const JsonObject& config) override {
-    if (config.containsKey("enabled")) {
+    if (config["enabled"].is<bool>()) {
       enabled_ = config["enabled"];
     } else {
       return false;
diff --git a/src/sensesp/transforms/frequency.cpp b/src/sensesp/transforms/frequency.cpp
index 406c04ce8..7624f85c5 100644
--- a/src/sensesp/transforms/frequency.cpp
+++ b/src/sensesp/transforms/frequency.cpp
@@ -34,7 +34,7 @@ String Frequency::get_config_schema() { return (kSchema); }
 bool Frequency::set_configuration(const JsonObject& config) {
   String const expected[] = {"multiplier"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/integrator.h b/src/sensesp/transforms/integrator.h
index d3730a56c..4a4b32600 100644
--- a/src/sensesp/transforms/integrator.h
+++ b/src/sensesp/transforms/integrator.h
@@ -48,11 +48,8 @@ class Integrator : public Transform<C, P> {
     doc["k"] = k;
   }
   virtual bool set_configuration(const JsonObject& config) override final {
-    String expected[] = {"k"};
-    for (auto str : expected) {
-      if (!config.containsKey(str)) {
-        return false;
-      }
+    if (!config["k"].is<P>()) {
+      return false;
     }
     k = config["k"];
     return true;
diff --git a/src/sensesp/transforms/lambda_transform.h b/src/sensesp/transforms/lambda_transform.h
index 5cdd9a226..87f0c90e8 100644
--- a/src/sensesp/transforms/lambda_transform.h
+++ b/src/sensesp/transforms/lambda_transform.h
@@ -232,7 +232,7 @@ class LambdaTransform : public Transform<IN, OUT> {
     ESP_LOGD(__FILENAME__, "Preparing to restore configuration from FS.");
     for (int i = 0; i < num_params_; i++) {
       const char* expected = param_info_[i].key;
-      if (!config.containsKey(expected)) {
+      if (!config[expected].is<JsonVariant>()) {
         ESP_LOGD(__FILENAME__, "Didn't find all keys.");
         return false;
       }
diff --git a/src/sensesp/transforms/median.cpp b/src/sensesp/transforms/median.cpp
index d4fb5b023..b53a4dde5 100644
--- a/src/sensesp/transforms/median.cpp
+++ b/src/sensesp/transforms/median.cpp
@@ -38,7 +38,7 @@ String Median::get_config_schema() { return (kSchema); }
 bool Median::set_configuration(const JsonObject& config) {
   String const expected[] = {"sample_size"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/moving_average.cpp b/src/sensesp/transforms/moving_average.cpp
index 85d66101a..5e6bd6f41 100644
--- a/src/sensesp/transforms/moving_average.cpp
+++ b/src/sensesp/transforms/moving_average.cpp
@@ -53,7 +53,7 @@ String MovingAverage::get_config_schema() { return (kSchema); }
 bool MovingAverage::set_configuration(const JsonObject& config) {
   String const expected[] = {"multiplier", "sample_size"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/press_repeater.cpp b/src/sensesp/transforms/press_repeater.cpp
index 79b48f6d8..5763a984e 100644
--- a/src/sensesp/transforms/press_repeater.cpp
+++ b/src/sensesp/transforms/press_repeater.cpp
@@ -67,7 +67,7 @@ String PressRepeater::get_config_schema() { return (kSchema); }
 bool PressRepeater::set_configuration(const JsonObject& config) {
   String const expected[] = {"repeat_start_interval", "repeat_interval"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/threshold.cpp b/src/sensesp/transforms/threshold.cpp
index 4e2734c85..e82bbad70 100644
--- a/src/sensesp/transforms/threshold.cpp
+++ b/src/sensesp/transforms/threshold.cpp
@@ -31,7 +31,7 @@ static const char kFloatSchema[] = R"({
 bool FloatThreshold::set_configuration(const JsonObject& config) {
   String const expected[] = {"min", "max", "in_range"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
@@ -61,7 +61,7 @@ static const char kIntSchema[] = R"({
 bool IntThreshold::set_configuration(const JsonObject& config) {
   String const expected[] = {"min", "max", "in_range"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/voltage_multiplier.cpp b/src/sensesp/transforms/voltage_multiplier.cpp
index 333bc654c..c6f00ec31 100644
--- a/src/sensesp/transforms/voltage_multiplier.cpp
+++ b/src/sensesp/transforms/voltage_multiplier.cpp
@@ -29,7 +29,7 @@ String VoltageMultiplier::get_config_schema() { return (kSchema); }
 bool VoltageMultiplier::set_configuration(const JsonObject& config) {
   String const expected[] = {"R1", "R2"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       return false;
     }
   }
diff --git a/src/sensesp/transforms/voltagedivider.cpp b/src/sensesp/transforms/voltagedivider.cpp
index 3f9e6b974..80658443a 100644
--- a/src/sensesp/transforms/voltagedivider.cpp
+++ b/src/sensesp/transforms/voltagedivider.cpp
@@ -30,7 +30,7 @@ String VoltageDividerR1::get_config_schema() { return (kSchemaR1); }
 bool VoltageDividerR1::set_configuration(const JsonObject& config) {
   String const expected[] = {"Vin", "R2"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       ESP_LOGE(
           __FILENAME__,
           "Cannot set VoltageDividerR1: configuration: missing json field %s\n",
@@ -73,7 +73,7 @@ String VoltageDividerR2::get_config_schema() { return (kSchemaR2); }
 bool VoltageDividerR2::set_configuration(const JsonObject& config) {
   String const expected[] = {"Vin", "R1"};
   for (auto str : expected) {
-    if (!config.containsKey(str)) {
+    if (!config[str].is<JsonVariant>()) {
       ESP_LOGE(
           __FILENAME__,
           "Cannot set VoltageDividerR2: configuration: missing json field %s\n",
diff --git a/src/sensesp/types/position.cpp b/src/sensesp/types/position.cpp
index 16df87fac..2a21b5758 100644
--- a/src/sensesp/types/position.cpp
+++ b/src/sensesp/types/position.cpp
@@ -8,7 +8,7 @@ void convertFromJson(JsonVariantConst src, Position &dst) {
   dst.longitude = src["longitude"].as<double>();
   dst.latitude = src["latitude"].as<double>();
 
-  if (src.containsKey("altitude")) {
+  if (src["altitude"].is<float>()) {
     dst.altitude = src["altitude"].as<float>();
   }
 }
@@ -17,7 +17,7 @@ void convertFromJson(JsonVariantConst src, ENUVector &dst) {
   dst.east = src["east"].as<float>();
   dst.north = src["north"].as<float>();
 
-  if (src.containsKey("up")) {
+  if (src["up"].is<float>()) {
     dst.up = src["up"].as<float>();
   }
 }
@@ -29,17 +29,17 @@ void convertFromJson(JsonVariantConst src, AttitudeVector &dst) {
 }
 
 bool canConvertFromJson(JsonVariantConst src, const Position & /*position*/) {
-  return src.containsKey("latitude") && src.containsKey("longitude");
+  return src["latitude"].is<double>() && src["longitude"].is<double>();
 }
 
 bool canConvertFromJson(JsonVariantConst src, const ENUVector & /*enu*/) {
-  return src.containsKey("east") && src.containsKey("north");
+  return src["east"].is<double>() && src["north"].is<double>();
 }
 
 bool canConvertFromJson(JsonVariantConst src,
                         const AttitudeVector & /*attitude*/) {
-  return src.containsKey("roll") && src.containsKey("pitch") &&
-         src.containsKey("yaw");
+  return src["roll"].is<float>() && src["pitch"].is<float>() &&
+         src["yaw"].is<float>();
 }
 
 void convertToJson(const Position &src, JsonVariant dst) {
diff --git a/src/sensesp/ui/ui_controls.cpp b/src/sensesp/ui/ui_controls.cpp
index 834d88c59..ae8f68876 100644
--- a/src/sensesp/ui/ui_controls.cpp
+++ b/src/sensesp/ui/ui_controls.cpp
@@ -20,7 +20,7 @@ String StringConfig::get_config_schema() {
 void StringConfig::get_configuration(JsonObject& doc) { doc["value"] = value_; }
 
 bool StringConfig::set_configuration(const JsonObject& config) {
-  if (!config.containsKey("value")) {
+  if (!config["value"].is<String>()) {
     return false;
   }
 
@@ -45,7 +45,7 @@ String NumberConfig::get_config_schema() {
 void NumberConfig::get_configuration(JsonObject& doc) { doc["value"] = value_; }
 
 bool NumberConfig::set_configuration(const JsonObject& config) {
-  if (!config.containsKey("value")) {
+  if (!config["value"].is<float>()) {
     return false;
   }
 
@@ -72,7 +72,7 @@ void CheckboxConfig::get_configuration(JsonObject& doc) {
 }
 
 bool CheckboxConfig::set_configuration(const JsonObject& config) {
-  if (!config.containsKey("value")) {
+  if (!config["value"].is<bool>()) {
     return false;
   }
 
@@ -120,7 +120,7 @@ String SelectConfig::get_config_schema() {
 void SelectConfig::get_configuration(JsonObject& doc) { doc["value"] = value_; }
 
 bool SelectConfig::set_configuration(const JsonObject& config) {
-  if (!config.containsKey("value")) {
+  if (!config["value"].is<String>()) {
     return false;
   }