diff --git a/src/app/App.cpp b/src/app/App.cpp
index f7ecb7a..5934a93 100644
--- a/src/app/App.cpp
+++ b/src/app/App.cpp
@@ -20,7 +20,7 @@ void appStart(const String& name) {
     error("No such app: \"%s\"\n", name.c_str());
     return;
   }
-  info("App instantiated: \"%s\" (heap usage: %d%%)", app->getName(), getHeapUsagePercent());
+  info("App loaded: \"%s\" (heap usage: %d%%)", app->getName(), getHeapUsagePercent());
 
   app->start();
   info("App started: \"%s\" (heap usage: %d%%)", app->getName(), getHeapUsagePercent());
diff --git a/src/app/App.h b/src/app/App.h
index d8323a5..4edb077 100644
--- a/src/app/App.h
+++ b/src/app/App.h
@@ -11,17 +11,16 @@ class App {
 
   const String path;
 
-  JsonDocument configJson;
+  JsonDocument configJsonDoc;
 
-  JsonObject config = configJson.to<JsonObject>();
+  JsonObject config = configJsonDoc.to<JsonObject>();
 
   bool dirty = true;
 
 public:
 
-  explicit App(const char *name) :
-      name(name),
-      path(String("/") + name + ".json") {
+  explicit App(const char *name) : name(name),
+                                   path(String("/") + name + ".json") {
     //
   }
 
@@ -32,7 +31,7 @@ public:
   }
 
   void start() {
-    configLoad();
+    configRead();
     _start();
     markDirty();
   }
@@ -88,6 +87,7 @@ protected:
     if (config[key].is<T>()) {
       return config[key].as<T>();
     }
+    warn("config key \"%s\" not found!", key);
     return fallback;
   }
 
@@ -116,51 +116,50 @@ protected:
     dirty = true;
   }
 
-  void configLoad() {
-    configJson.clear();
+  bool deserializeConfig(File file) {
+    if (deserializeJson(configJsonDoc, file) != DeserializationError::Ok) {
+      error("failed to deserialize config: %s", file.path());
+      return false;
+    }
+    if (!configJsonDoc.is<JsonObject>()) {
+      error("not a json-object: %s", file.path());
+      return false;
+    }
+    char buffer[256];
+    serializeJson(configJsonDoc, buffer, sizeof buffer);
+    info("config loaded: %s => %s", path.c_str(), buffer);
+    config = configJsonDoc.as<JsonObject>();
+    return true;
+  }
+
+  void configRead() {
     auto file = LittleFS.open(path, "r");
     if (!file) {
       error("failed to open file for config read: %s", path.c_str());
       return;
     }
-
-    if (deserializeJson(configJson, file)) {
-      info("config loaded: %s", path.c_str());
-    } else {
-      error("failed to load config: %s", path.c_str());
+    if (!deserializeConfig(file)) {
+      configJsonDoc.clear();
+      config = configJsonDoc.to<JsonObject>();
     }
     file.close();
-
-    config = configJson.to<JsonObject>();
-
-    char buffer[256];
-    serializeJsonPretty(configJson, buffer, sizeof buffer);
-    Serial.println(buffer);
   }
 
-  void configSave() {
-    auto file = LittleFS.open(path, "w");
-    if (!file) {
+  void configWrite() const {
+    auto write = LittleFS.open(path, "w");
+    if (!write) {
       error("failed to open file for config write: %s", path.c_str());
       return;
     }
-
-    if (serializeJson(configJson, file)) {
-      info("config written: %s", path.c_str());
+    const auto size = measureJson(configJsonDoc);
+    if (serializeJson(configJsonDoc, write) == size) {
+      char buffer[256];
+      serializeJson(configJsonDoc, buffer, sizeof buffer);
+      info("config written: %s => %s", path.c_str(), buffer);
     } else {
       error("failed to write config: %s", path.c_str());
     }
-    file.close();
-
-    auto file2 = LittleFS.open(path, "r");
-    if (file2) {
-      while (file2.available()) {
-        Serial.write(file2.read());
-      }
-      file2.close();
-    } else {
-      Serial.println("Failed to open file2 for reading");
-    }
+    write.close();
   }
 
 };
diff --git a/src/app/AppMatch.h b/src/app/AppMatch.h
index fc83c77..ccc02cf 100644
--- a/src/app/AppMatch.h
+++ b/src/app/AppMatch.h
@@ -43,7 +43,7 @@ class AppMatch final : public App {
 public:
 
   explicit AppMatch()
-      : App(APP_MATCH_NAME) {
+    : App(APP_MATCH_NAME) {
     //
   }
 
@@ -54,7 +54,7 @@ public:
       if (seconds > 0 && configMillis != newMillis) {
         configMillis = newMillis;
         configSet(CONFIG_SECONDS_KEY, seconds);
-        configSave();
+        configWrite();
         return true;
       }
     }
@@ -64,7 +64,11 @@ public:
 protected:
 
   void _start() override {
-    configMillis = configGet<unsigned long>(CONFIG_SECONDS_KEY, CONFIG_SECONDS_DEFAULT) * 1000;
+    const auto seconds = configGet<unsigned long>(CONFIG_SECONDS_KEY, CONFIG_SECONDS_DEFAULT);
+    info("config:");
+    info("  seconds = %ld", seconds);
+
+    configMillis = seconds * 1000;
     totalMillis = configMillis;
     setState(PAUSE);
   }