diff --git a/src/app/application.cpp b/src/app/application.cpp
index 26669d8e9..3f42b13e6 100644
--- a/src/app/application.cpp
+++ b/src/app/application.cpp
@@ -226,6 +226,7 @@ namespace
 Application::Application(int &argc, char **argv)
     : BaseApplication(argc, argv)
     , m_commandLineArgs(parseCommandLine(Application::arguments()))
+    , m_storeInstanceName(SETTINGS_KEY(u"InstanceName"_s))
     , m_storeFileLoggerEnabled(FILELOGGER_SETTINGS_KEY(u"Enabled"_s))
     , m_storeFileLoggerBackup(FILELOGGER_SETTINGS_KEY(u"Backup"_s))
     , m_storeFileLoggerDeleteOld(FILELOGGER_SETTINGS_KEY(u"DeleteOld"_s))
@@ -360,6 +361,23 @@ const QBtCommandLineParameters &Application::commandLineArgs() const
     return m_commandLineArgs;
 }
 
+QString Application::instanceName() const
+{
+    return m_storeInstanceName;
+}
+
+void Application::setInstanceName(const QString &name)
+{
+    if (name == instanceName())
+        return;
+
+    m_storeInstanceName = name;
+#ifndef DISABLE_GUI
+    if (MainWindow *mw = mainWindow())
+        mw->setTitleSuffix(name);
+#endif
+}
+
 int Application::memoryWorkingSetLimit() const
 {
     return m_storeMemoryWorkingSetLimit.get(512);
@@ -880,7 +898,8 @@ int Application::exec()
         const WindowState windowState = (m_startupProgressDialog->windowState() & Qt::WindowMinimized)
                 ? WindowState::Minimized : WindowState::Normal;
 #endif
-        m_window = new MainWindow(this, windowState);
+        m_window = new MainWindow(this, windowState, instanceName());
+
         delete m_startupProgressDialog;
 #endif // DISABLE_GUI
 
diff --git a/src/app/application.h b/src/app/application.h
index 678325949..3218f3d71 100644
--- a/src/app/application.h
+++ b/src/app/application.h
@@ -105,6 +105,9 @@ public:
     bool callMainInstance();
     const QBtCommandLineParameters &commandLineArgs() const;
 
+    QString instanceName() const override;
+    void setInstanceName(const QString &name) override;
+
     // FileLogger properties
     bool isFileLoggerEnabled() const override;
     void setFileLoggerEnabled(bool value) override;
@@ -194,6 +197,7 @@ private:
 
     QList<QBtCommandLineParameters> m_paramsQueue;
 
+    SettingValue<QString> m_storeInstanceName;
     SettingValue<bool> m_storeFileLoggerEnabled;
     SettingValue<bool> m_storeFileLoggerBackup;
     SettingValue<bool> m_storeFileLoggerDeleteOld;
diff --git a/src/base/interfaces/iapplication.h b/src/base/interfaces/iapplication.h
index 5f8eb18ea..211a9ea20 100644
--- a/src/base/interfaces/iapplication.h
+++ b/src/base/interfaces/iapplication.h
@@ -61,6 +61,9 @@ class IApplication
 public:
     virtual ~IApplication() = default;
 
+    virtual QString instanceName() const = 0;
+    virtual void setInstanceName(const QString &name) = 0;
+
     // FileLogger properties
     virtual bool isFileLoggerEnabled() const = 0;
     virtual void setFileLoggerEnabled(bool value) = 0;
diff --git a/src/gui/advancedsettings.cpp b/src/gui/advancedsettings.cpp
index 187194d02..dac681628 100644
--- a/src/gui/advancedsettings.cpp
+++ b/src/gui/advancedsettings.cpp
@@ -79,6 +79,7 @@ namespace
         CONFIRM_RECHECK_TORRENT,
         RECHECK_COMPLETED,
         // UI related
+        APP_INSTANCE_NAME,
         LIST_REFRESH,
         RESOLVE_HOSTS,
         RESOLVE_COUNTRIES,
@@ -280,6 +281,8 @@ void AdvancedSettings::saveAdvancedSettings() const
     session->setBlockPeersOnPrivilegedPorts(m_checkBoxBlockPeersOnPrivilegedPorts.isChecked());
     // Recheck torrents on completion
     pref->recheckTorrentsOnCompletion(m_checkBoxRecheckCompleted.isChecked());
+    // Customize application instance name
+    app()->setInstanceName(m_lineEditAppInstanceName.text());
     // Transfer list refresh interval
     session->setRefreshInterval(m_spinBoxListRefresh.value());
     // Peer resolution
@@ -723,6 +726,10 @@ void AdvancedSettings::loadAdvancedSettings()
     // Recheck completed torrents
     m_checkBoxRecheckCompleted.setChecked(pref->recheckTorrentsOnCompletion());
     addRow(RECHECK_COMPLETED, tr("Recheck torrents on completion"), &m_checkBoxRecheckCompleted);
+    // Customize application instance name
+    m_lineEditAppInstanceName.setText(app()->instanceName());
+    m_lineEditAppInstanceName.setToolTip(tr("It appends the text to the window title to help distinguish qBittorent instances"));
+    addRow(APP_INSTANCE_NAME, tr("Customize application instance name"), &m_lineEditAppInstanceName);
     // Refresh interval
     m_spinBoxListRefresh.setMinimum(30);
     m_spinBoxListRefresh.setMaximum(99999);
diff --git a/src/gui/advancedsettings.h b/src/gui/advancedsettings.h
index 8dbc39fd7..91473c8e2 100644
--- a/src/gui/advancedsettings.h
+++ b/src/gui/advancedsettings.h
@@ -82,7 +82,7 @@ private:
               m_checkBoxSuggestMode, m_checkBoxSpeedWidgetEnabled, m_checkBoxIDNSupport, m_checkBoxConfirmRemoveTrackerFromAllTorrents;
     QComboBox m_comboBoxInterface, m_comboBoxInterfaceAddress, m_comboBoxDiskIOReadMode, m_comboBoxDiskIOWriteMode, m_comboBoxUtpMixedMode, m_comboBoxChokingAlgorithm,
               m_comboBoxSeedChokingAlgorithm, m_comboBoxResumeDataStorage;
-    QLineEdit m_pythonExecutablePath, m_lineEditAnnounceIP, m_lineEditDHTBootstrapNodes;
+    QLineEdit m_lineEditAppInstanceName, m_pythonExecutablePath, m_lineEditAnnounceIP, m_lineEditDHTBootstrapNodes;
 
 #ifndef QBT_USES_LIBTORRENT2
     QSpinBox m_spinBoxCache, m_spinBoxCacheTTL;
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index edd8004b9..e1d6cf28c 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -122,7 +122,7 @@ namespace
     }
 }
 
-MainWindow::MainWindow(IGUIApplication *app, WindowState initialState)
+MainWindow::MainWindow(IGUIApplication *app, const WindowState initialState, const QString &titleSuffix)
     : GUIApplicationComponent(app)
     , m_ui(new Ui::MainWindow)
     , m_storeExecutionLogEnabled(EXECUTIONLOG_SETTINGS_KEY(u"Enabled"_s))
@@ -134,9 +134,10 @@ MainWindow::MainWindow(IGUIApplication *app, WindowState initialState)
 {
     m_ui->setupUi(this);
 
+    setTitleSuffix(titleSuffix);
+
     Preferences *const pref = Preferences::instance();
     m_uiLocked = pref->isUILocked();
-    setWindowTitle(QStringLiteral("qBittorrent " QBT_VERSION));
     m_displaySpeedInTitle = pref->speedInTitleBar();
     // Setting icons
 #ifndef Q_OS_MACOS
@@ -524,6 +525,16 @@ void MainWindow::setDownloadTrackerFavicon(const bool value)
     m_storeDownloadTrackerFavicon = value;
 }
 
+void MainWindow::setTitleSuffix(const QString &suffix)
+{
+    const auto emDash = QChar(0x2014);
+    const QString separator = u' ' + emDash + u' ';
+    m_windowTitle = QStringLiteral("qBittorrent " QBT_VERSION)
+        + (!suffix.isEmpty() ? (separator + suffix) : QString());
+
+    setWindowTitle(m_windowTitle);
+}
+
 void MainWindow::addToolbarContextMenu()
 {
     const Preferences *const pref = Preferences::instance();
@@ -1485,23 +1496,24 @@ void MainWindow::loadPreferences()
 void MainWindow::reloadSessionStats()
 {
     const BitTorrent::SessionStatus &status = BitTorrent::Session::instance()->status();
+    const QString downloadRate = Utils::Misc::friendlyUnit(status.payloadDownloadRate, true);
+    const QString uploadRate = Utils::Misc::friendlyUnit(status.payloadUploadRate, true);
 
     // update global information
 #ifdef Q_OS_MACOS
     m_badger->updateSpeed(status.payloadDownloadRate, status.payloadUploadRate);
 #else
     const auto toolTip = u"%1\n%2"_s.arg(
-        tr("DL speed: %1", "e.g: Download speed: 10 KiB/s").arg(Utils::Misc::friendlyUnit(status.payloadDownloadRate, true))
-        , tr("UP speed: %1", "e.g: Upload speed: 10 KiB/s").arg(Utils::Misc::friendlyUnit(status.payloadUploadRate, true)));
+        tr("DL speed: %1", "e.g: Download speed: 10 KiB/s").arg(downloadRate)
+        , tr("UP speed: %1", "e.g: Upload speed: 10 KiB/s").arg(uploadRate));
     app()->desktopIntegration()->setToolTip(toolTip); // tray icon
 #endif  // Q_OS_MACOS
 
     if (m_displaySpeedInTitle)
     {
-        setWindowTitle(tr("[D: %1, U: %2] qBittorrent %3", "D = Download; U = Upload; %3 is qBittorrent version")
-            .arg(Utils::Misc::friendlyUnit(status.payloadDownloadRate, true)
-                , Utils::Misc::friendlyUnit(status.payloadUploadRate, true)
-                , QStringLiteral(QBT_VERSION)));
+        const QString title = tr("[D: %1, U: %2] %3", "D = Download; U = Upload; %3 is the rest of the window title")
+            .arg(downloadRate, uploadRate, m_windowTitle);
+        setWindowTitle(title);
     }
 }
 
@@ -1621,7 +1633,7 @@ void MainWindow::on_actionSpeedInTitleBar_triggered()
     if (m_displaySpeedInTitle)
         reloadSessionStats();
     else
-        setWindowTitle(QStringLiteral("qBittorrent " QBT_VERSION));
+        setWindowTitle(m_windowTitle);
 }
 
 void MainWindow::on_actionRSSReader_triggered()
diff --git a/src/gui/mainwindow.h b/src/gui/mainwindow.h
index 4fc08a253..d122cdbb3 100644
--- a/src/gui/mainwindow.h
+++ b/src/gui/mainwindow.h
@@ -84,7 +84,7 @@ class MainWindow final : public GUIApplicationComponent<QMainWindow>
     Q_DISABLE_COPY_MOVE(MainWindow)
 
 public:
-    explicit MainWindow(IGUIApplication *app, WindowState initialState = WindowState::Normal);
+    explicit MainWindow(IGUIApplication *app, WindowState initialState = WindowState::Normal, const QString &titleSuffix = {});
     ~MainWindow() override;
 
     QWidget *currentTabWidget() const;
@@ -97,12 +97,12 @@ public:
     Log::MsgTypes executionLogMsgTypes() const;
     void setExecutionLogMsgTypes(Log::MsgTypes value);
 
-    // Notifications properties
-
     // Misc properties
     bool isDownloadTrackerFavicon() const;
     void setDownloadTrackerFavicon(bool value);
 
+    void setTitleSuffix(const QString &suffix);
+
     void activate();
     void cleanup();
 
@@ -207,6 +207,7 @@ private:
 
     QFileSystemWatcher *m_executableWatcher = nullptr;
     // GUI related
+    QString m_windowTitle;
     bool m_posInitialized = false;
     bool m_neverShown = true;
     QPointer<QTabWidget> m_tabs;
diff --git a/src/webui/api/appcontroller.cpp b/src/webui/api/appcontroller.cpp
index 8ea29d568..073ada234 100644
--- a/src/webui/api/appcontroller.cpp
+++ b/src/webui/api/appcontroller.cpp
@@ -361,6 +361,8 @@ void AppController::preferencesAction()
     data[u"torrent_file_size_limit"_s] = pref->getTorrentFileSizeLimit();
     // Recheck completed torrents
     data[u"recheck_completed_torrents"_s] = pref->recheckTorrentsOnCompletion();
+    // Customize application instance name
+    data[u"app_instance_name"_s] = app()->instanceName();
     // Refresh interval
     data[u"refresh_interval"_s] = session->refreshInterval();
     // Resolve peer countries
@@ -943,6 +945,9 @@ void AppController::setPreferencesAction()
     // Recheck completed torrents
     if (hasKey(u"recheck_completed_torrents"_s))
         pref->recheckTorrentsOnCompletion(it.value().toBool());
+    // Customize application instance name
+    if (hasKey(u"app_instance_name"_s))
+        app()->setInstanceName(it.value().toString());
     // Refresh interval
     if (hasKey(u"refresh_interval"_s))
         session->setRefreshInterval(it.value().toInt());
diff --git a/src/webui/webapplication.h b/src/webui/webapplication.h
index a6f2ede6a..aeee95863 100644
--- a/src/webui/webapplication.h
+++ b/src/webui/webapplication.h
@@ -53,7 +53,7 @@
 #include "base/utils/version.h"
 #include "api/isessionmanager.h"
 
-inline const Utils::Version<3, 2> API_VERSION {2, 10, 3};
+inline const Utils::Version<3, 2> API_VERSION {2, 10, 4};
 
 class QTimer;
 
diff --git a/src/webui/www/private/css/style.css b/src/webui/www/private/css/style.css
index f05ae3e78..4387c43a2 100644
--- a/src/webui/www/private/css/style.css
+++ b/src/webui/www/private/css/style.css
@@ -241,7 +241,7 @@ a.propButton img {
 .contextMenu li a {
     color: var(--color-text-default);
     display: block;
-    font-family: tahoma, arial, sans-serif;
+    font-family: Tahoma, Arial, sans-serif;
     font-size: 12px;
     padding: 5px 20px 5px 5px;
     text-decoration: none;
diff --git a/src/webui/www/private/scripts/client.js b/src/webui/www/private/scripts/client.js
index 65bd2388a..d6f108678 100644
--- a/src/webui/www/private/scripts/client.js
+++ b/src/webui/www/private/scripts/client.js
@@ -36,7 +36,8 @@ window.qBittorrent.Client = (() => {
             genHash: genHash,
             getSyncMainDataInterval: getSyncMainDataInterval,
             isStopped: isStopped,
-            stop: stop
+            stop: stop,
+            mainTitle: mainTitle
         };
     };
 
@@ -67,6 +68,15 @@ window.qBittorrent.Client = (() => {
         stopped = true;
     };
 
+    const mainTitle = () => {
+        const emDash = '\u2014';
+        const qbtVersion = window.qBittorrent.Cache.qbtVersion.get();
+        const suffix = window.qBittorrent.Cache.preferences.get()['app_instance_name'] || '';
+        const title = `qBittorrent ${qbtVersion} QBT_TR(WebUI)QBT_TR[CONTEXT=OptionsDialog]`
+            + ((suffix.length > 0) ? ` ${emDash} ${suffix}` : '');
+        return title;
+    };
+
     return exports();
 })();
 Object.freeze(window.qBittorrent.Client);
@@ -275,7 +285,7 @@ window.addEventListener("DOMContentLoaded", function() {
     initializeWindows();
 
     // Show Top Toolbar is enabled by default
-    let showTopToolbar = LocalPreferences.get('show_top_toolbar', 'true') == "true";
+    let showTopToolbar = LocalPreferences.get('show_top_toolbar', 'true') === "true";
     if (!showTopToolbar) {
         $('showTopToolbarLink').firstChild.style.opacity = '0';
         $('mochaToolbar').addClass('invisible');
@@ -296,7 +306,7 @@ window.addEventListener("DOMContentLoaded", function() {
         $('filtersColumn_handle').addClass('invisible');
     }
 
-    let speedInTitle = LocalPreferences.get('speed_in_browser_title_bar') == "true";
+    let speedInTitle = LocalPreferences.get('speed_in_browser_title_bar') === "true";
     if (!speedInTitle)
         $('speedInBrowserTitleBarLink').firstChild.style.opacity = '0';
 
@@ -873,14 +883,13 @@ window.addEventListener("DOMContentLoaded", function() {
         transfer_info += " (" + window.qBittorrent.Misc.friendlyUnit(serverState.up_info_data, false) + ")";
         $("UpInfos").set('html', transfer_info);
 
-        const qbtVersion = window.qBittorrent.Cache.qbtVersion.get();
+        document.title = (speedInTitle
+                ? (`QBT_TR([D: %1, U: %2])QBT_TR[CONTEXT=MainWindow] `
+                    .replace("%1", window.qBittorrent.Misc.friendlyUnit(serverState.dl_info_speed, true))
+                    .replace("%2", window.qBittorrent.Misc.friendlyUnit(serverState.up_info_speed, true)))
+                : '')
+            + window.qBittorrent.Client.mainTitle();
 
-        if (speedInTitle) {
-            document.title = "QBT_TR([D: %1, U: %2] qBittorrent %3)QBT_TR[CONTEXT=MainWindow]".replace("%1", window.qBittorrent.Misc.friendlyUnit(serverState.dl_info_speed, true)).replace("%2", window.qBittorrent.Misc.friendlyUnit(serverState.up_info_speed, true)).replace("%3", qbtVersion);
-            document.title += " QBT_TR(Web UI)QBT_TR[CONTEXT=OptionsDialog]";
-        }
-        else
-            document.title = ("qBittorrent " + qbtVersion + " QBT_TR(Web UI)QBT_TR[CONTEXT=OptionsDialog]");
         $('freeSpaceOnDisk').set('html', 'QBT_TR(Free space: %1)QBT_TR[CONTEXT=HttpServer]'.replace("%1", window.qBittorrent.Misc.friendlyUnit(serverState.free_space_on_disk)));
         $('DHTNodes').set('html', 'QBT_TR(DHT: %1 nodes)QBT_TR[CONTEXT=StatusBar]'.replace("%1", serverState.dht_nodes));
 
diff --git a/src/webui/www/private/scripts/mocha-init.js b/src/webui/www/private/scripts/mocha-init.js
index 613f0fe15..d46ff1664 100644
--- a/src/webui/www/private/scripts/mocha-init.js
+++ b/src/webui/www/private/scripts/mocha-init.js
@@ -1157,7 +1157,8 @@ const initializeWindows = function() {
                 url: 'api/v2/app/shutdown',
                 method: 'post',
                 onSuccess: function() {
-                    document.write('<!doctype html><html lang="${LANG}"><head> <meta charset="UTF-8"> <meta name="color-scheme" content="light dark" /> <title>QBT_TR(qBittorrent has been shutdown)QBT_TR[CONTEXT=HttpServer]</title></head><body> <h1 style="text-align: center;">QBT_TR(qBittorrent has been shutdown)QBT_TR[CONTEXT=HttpServer]</h1></body></html>');
+                    const shutdownMessage = 'QBT_TR(%1 has been shutdown)QBT_TR[CONTEXT=HttpServer]'.replace("%1", window.qBittorrent.Client.mainTitle());
+                    document.write(`<!doctype html><html lang="${LANG}"><head> <meta charset="UTF-8"> <meta name="color-scheme" content="light dark"> <title>${shutdownMessage}</title> <style>* {font-family: Arial, Helvetica, sans-serif;}</style></head><body> <h1 style="text-align: center;">${shutdownMessage}</h1></body></html>`);
                     document.close();
                     window.stop();
                     window.qBittorrent.Client.stop();
diff --git a/src/webui/www/private/views/preferences.html b/src/webui/www/private/views/preferences.html
index ab62b96ec..624560149 100644
--- a/src/webui/www/private/views/preferences.html
+++ b/src/webui/www/private/views/preferences.html
@@ -1043,6 +1043,14 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
                     <input type="checkbox" id="recheckTorrentsOnCompletion">
                 </td>
             </tr>
+            <tr>
+                <td>
+                    <label for="appInstanceName">QBT_TR(Customize application instance name:)QBT_TR[CONTEXT=OptionsDialog]</label>
+                </td>
+                <td>
+                    <input type="text" id="appInstanceName" style="width: 15em;" title="QBT_TR(It appends the text to the window title to help distinguish qBittorent instances)QBT_TR[CONTEXT=OptionsDialog]" />
+                </td>
+            </tr>
             <tr>
                 <td>
                     <label for="refreshInterval">QBT_TR(Refresh interval:)QBT_TR[CONTEXT=OptionsDialog]</label>
@@ -2301,6 +2309,7 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
                     $('saveResumeDataInterval').setProperty('value', pref.save_resume_data_interval);
                     $('torrentFileSizeLimit').setProperty('value', (pref.torrent_file_size_limit / 1024 / 1024));
                     $('recheckTorrentsOnCompletion').setProperty('checked', pref.recheck_completed_torrents);
+                    $('appInstanceName').setProperty('value', pref.app_instance_name);
                     $('refreshInterval').setProperty('value', pref.refresh_interval);
                     $('resolvePeerCountries').setProperty('checked', pref.resolve_peer_countries);
                     $('reannounceWhenAddressChanged').setProperty('checked', pref.reannounce_when_address_changed);
@@ -2746,6 +2755,7 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
             settings['save_resume_data_interval'] = Number($('saveResumeDataInterval').getProperty('value'));
             settings['torrent_file_size_limit'] = ($('torrentFileSizeLimit').getProperty('value') * 1024 * 1024);
             settings['recheck_completed_torrents'] = $('recheckTorrentsOnCompletion').getProperty('checked');
+            settings['app_instance_name'] = $('appInstanceName').getProperty('value');
             settings['refresh_interval'] = Number($('refreshInterval').getProperty('value'));
             settings['resolve_peer_countries'] = $('resolvePeerCountries').getProperty('checked');
             settings['reannounce_when_address_changed'] = $('reannounceWhenAddressChanged').getProperty('checked');