diff --git a/keys.txt b/keys.txt
new file mode 100644
index 0000000..da4c8cd
--- /dev/null
+++ b/keys.txt
@@ -0,0 +1,2 @@
+AIzaSy...
+AIzaSy...
\ No newline at end of file
diff --git a/main.cpp b/main.cpp
index 4c22519..e350bfb 100644
--- a/main.cpp
+++ b/main.cpp
@@ -14,6 +14,7 @@ using json = nlohmann::json;
 
 enum getJsonBehavior { normal, retryOnCommentsDisabled, returnErrorIfPlaylistNotFound };
 
+set<string> setFromVector(vector<string> vec);
 vector<string> getFileContent(string filePath);
 json getJson(unsigned short threadId, string url, string directoryPath, getJsonBehavior behavior = normal);
 void createDirectory(string path),
@@ -29,21 +30,24 @@ bool doesFileExist(string filePath),
      writeFile(unsigned short threadId, string filePath, string option, string toWrite);
 
 #define USE_YT_LEMNOSLIFE_COM_NO_KEY_SERVICE
-#define API_KEY "AIzaSy..."
 #define THREADS_NUMBER 10
 
 #define PRINT(threadId, x) { ostringstream toPrint; toPrint << threadId << ": " << x; print(&toPrint); }
 #define DEFAULT_THREAD_ID 0
 
 mutex printMutex,
-      channelsAlreadyTreatedAndToTreatMutex;
+      channelsAlreadyTreatedAndToTreatMutex,
+      quotaMutex;
 set<string> channelsAlreadyTreated,
     channelsToTreat;
+vector<string> keys;
 unsigned int commentsCount = 0,
              commentsPerSecondCount = 0,
              requestsPerChannel = 0;
 string CHANNELS_DIRECTORY = "channels/",
-       CHANNELS_FILE_PATH = "channels.txt";
+       CHANNELS_FILE_PATH = "channels.txt",
+       KEYS_FILE_PATH = "keys.txt",
+       apiKey = ""; // Will firstly be filled with `KEYS_FILE_PATH` first line.
 
 int main()
 {
@@ -52,7 +56,10 @@ int main()
     // On a restart, `CHANNELS_FILE_PATH` is read and every channel not found in `CHANNELS_DIRECTORY` is added to `channelsToTreat` or `channelsToTreat` otherwise before continuing, as if `CHANNELS_FILE_PATH` was containing a **treated** starting set.
     vector<string> channelsVec = getFileContent(CHANNELS_FILE_PATH);
     // Note that using `set`s makes the search faster but we lose the `channels.txt` lines order.
-    channelsToTreat = set(channelsVec.begin(), channelsVec.end());
+    channelsToTreat = setFromVector(channelsVec);
+
+    keys = getFileContent(KEYS_FILE_PATH);
+    apiKey = keys[0];
 
     createDirectory(CHANNELS_DIRECTORY);
 
@@ -332,6 +339,11 @@ string getDate()
     return toString.str();
 }
 
+set<string> setFromVector(vector<string> vec)
+{
+    return set(vec.begin(), vec.end());
+}
+
 vector<string> getFileContent(string filePath)
 {
     vector<string> lines;
@@ -347,7 +359,7 @@ json getJson(unsigned short threadId, string url, string directoryPath, getJsonB
 #ifdef USE_YT_LEMNOSLIFE_COM_NO_KEY_SERVICE
     string finalUrl = "https://yt.lemnoslife.com/noKey/" + url;
 #else
-    string finalUrl = "https://www.googleapis.com/youtube/v3/" + url + "&key=" + API_KEY;
+    string finalUrl = "https://www.googleapis.com/youtube/v3/" + url + "&key=" + apiKey;
 #endif
     string content = getHttps(finalUrl);
     json data;
@@ -363,8 +375,19 @@ json getJson(unsigned short threadId, string url, string directoryPath, getJsonB
 
     if(data.contains("error"))
     {
-        PRINT(threadId, "Found error in JSON at URL: " << finalUrl << " for content: " << content << " !")
         string reason = data["error"]["errors"][0]["reason"];
+        // Contrarily to YouTube operational API no-key service we don't rotate keys in `KEYS_FILE_PATH`, as we keep them in memory here.
+        if(reason == "quotaExceeded")
+        {
+            quotaMutex.lock();
+            keys.erase(keys.begin());
+            keys.push_back(apiKey);
+            PRINT(threadId, "No more quota on " << apiKey << " switching to " << keys[0] << ".")
+            apiKey = keys[0];
+            quotaMutex.unlock();
+            return getJson(threadId, url, directoryPath);
+        }
+        PRINT(threadId, "Found error in JSON at URL: " << finalUrl << " for content: " << content << " !")
         if(reason != "commentsDisabled" || behavior == retryOnCommentsDisabled)
         {
             return reason == "playlistNotFound" && behavior == returnErrorIfPlaylistNotFound ? data : getJson(threadId, url, directoryPath);