diff --git a/src/esp.h b/src/esp.h
index 7180f6b..cfa0034 100644
--- a/src/esp.h
+++ b/src/esp.h
@@ -17,8 +17,8 @@ namespace HaESP {
         uint8_t hfrag;
         ESP.getHeapStats(&hfree, &hmax, &hfrag);
 
-        char value[256];
-        sprintf(value, "{\"fragmentation\":%d,\"heap\":{\"Heap free\":\"%d B\",\"Heap max free block\":\"%d B\"}}", hfrag, hfree, hmax);
+        char value[128];
+        snprintf_P(value, sizeof(value),  PSTR("{\"fragmentation\":%d,\"heap\":{\"Heap free\":\"%d B\",\"Heap max free block\":\"%d B\"}}"), hfrag, hfree, hmax);
         Sensor::mapSensors["heap_fragmentation"]->updateState(value);
         Sensor::mapSensors["heap_free"]->updateState(to_string(hfree).c_str());
         Sensor::mapSensors["heap_max_free_block"]->updateState(to_string(hmax).c_str());
diff --git a/src/ha.h b/src/ha.h
index 364fef8..0299def 100644
--- a/src/ha.h
+++ b/src/ha.h
@@ -7,6 +7,7 @@ using namespace std;
 
 #define JSON_SIZE   512
 #define TOPIC_SIZE  255
+#define BASE_TOPIC  "homeassistant/%s/%s/%s"
 
 namespace Ha {
     uint16_t(*publisher)(const char* topic, const char* message);
@@ -116,12 +117,13 @@ namespace Ha {
         }
 
     protected:
-        virtual void buildUniqueId(char* uniqueId) {
-            sprintf(uniqueId, "%s_%s", MAIN_DEVICE_ID, id);
+        char uniqueId[50];
+        virtual void buildUniqueId() {
+            snprintf(uniqueId, sizeof(uniqueId), "%s_%s", MAIN_DEVICE_ID, id);
         }
 
         virtual void buildConfigTopic() {
-            sprintf(configTopic, "homeassistant/%s/%s/%s/config", type, MAIN_DEVICE_ID, id);
+            snprintf(configTopic, sizeof(configTopic), BASE_TOPIC"/config", type, MAIN_DEVICE_ID, id);
         }
 
         virtual void buildComponentConfig(JsonDocument& jsonDoc) = 0;
@@ -131,8 +133,7 @@ namespace Ha {
             if (entityCategory) jsonDoc["entity_category"] = entityCategory;
             if (deviceClass) jsonDoc["device_class"] = deviceClass;
             jsonDoc["name"] = name;
-            char uniqueId[50];
-            buildUniqueId(uniqueId);
+            buildUniqueId();
             jsonDoc["unique_id"] = uniqueId;
             buildConfigTopic();
 
@@ -261,7 +262,7 @@ namespace Ha {
         static unordered_map<string, Command*> mapCommands;
 
         Command(const char* name, const char* id, const char* type, onMessage f) : Component(name, id, type), f(f) {
-            sprintf(commandTopic, "homeassistant/%s/%s/%s/set", type, MAIN_DEVICE_ID, id);
+            snprintf(commandTopic, sizeof(commandTopic),  BASE_TOPIC"/set", type, MAIN_DEVICE_ID, id);
             mapCommands.insert({ string(commandTopic), this });
         }
 
@@ -297,7 +298,7 @@ namespace Ha {
         StateConfig(Component* cmp) : cmp(cmp) {}
 
         void withStateTopic() {
-            sprintf(stateTopic, "homeassistant/%s/%s/%s/state", cmp->type, MAIN_DEVICE_ID, cmp->id);
+            snprintf(stateTopic, sizeof(stateTopic),  BASE_TOPIC"/state", cmp->type, MAIN_DEVICE_ID, cmp->id);
         }
 
         void updateState(const char* message) {
@@ -336,9 +337,7 @@ namespace Ha {
             : Command(name, id, "number", f), StateConfig(this), min(min), max(max), step(step) {}
 
         void updateState(unsigned int value) {
-            char message[32];
-            sprintf(message, "%u", value);
-            StateConfig::updateState(message);
+            StateConfig::updateState(to_string(value).c_str());
         }
 
         void restoreFromState() {
@@ -366,17 +365,17 @@ namespace Ha {
         }
 
     protected:
-        void buildUniqueId(char* uniqueId) override {
+        void buildUniqueId() override {
             if (multiValueComponent && deviceClass) {
-                sprintf(uniqueId, "%s_%s_%s", MAIN_DEVICE_ID, deviceClass, id);
+                snprintf(uniqueId, sizeof(uniqueId),  "%s_%s_%s", MAIN_DEVICE_ID, deviceClass, id);
             } else {
-                Component::buildUniqueId(uniqueId);
+                Component::buildUniqueId();
             }
         }
 
         void buildConfigTopic() override {
             if (multiValueComponent && deviceClass) {
-                sprintf(configTopic, "homeassistant/%s/%s/%s_%s/config", type, MAIN_DEVICE_ID, deviceClass, id);
+                snprintf(configTopic, sizeof(configTopic),  BASE_TOPIC"_%s""/config", type, MAIN_DEVICE_ID, deviceClass, id);
             } else {
                 Component::buildConfigTopic();
             }