diff --git a/src/color_convert.cc b/src/color_convert.cc
index 244b6c5c40..4af9433fbf 100644
--- a/src/color_convert.cc
+++ b/src/color_convert.cc
@@ -33,7 +33,7 @@ TogglRgbColor ColorConverter::GetRgbAdaptiveColor(const std::string &hexColor, T
     return hsvToRgb(hsv);
 }
 
-TogglHsvColor ColorConverter::adjustColor(TogglHsvColor hsvColor, TogglAdaptiveColor type) {
+TogglHsvColor ColorConverter::adjustColor(const TogglHsvColor &hsvColor, TogglAdaptiveColor type) {
     switch (type) {
     case AdaptiveColorShapeOnLightBackground:
         return { hsvColor.h, hsvColor.s, hsvColor.v };
@@ -49,7 +49,7 @@ TogglHsvColor ColorConverter::adjustColor(TogglHsvColor hsvColor, TogglAdaptiveC
     return hsvColor;
 }
 
-TogglHsvColor ColorConverter::rgbToHsv(TogglRgbColor rgbColor)
+TogglHsvColor ColorConverter::rgbToHsv(const TogglRgbColor &rgbColor)
 {
     double r = rgbColor.r;
     double g = rgbColor.g;
@@ -104,7 +104,7 @@ TogglRgbColor ColorConverter::hexToRgb(std::string hex)
     return { r, g, b };
 }
 
-TogglRgbColor ColorConverter::hsvToRgb(TogglHsvColor hsvColor) {
+TogglRgbColor ColorConverter::hsvToRgb(const TogglHsvColor &hsvColor) {
     double h = hsvColor.h;
     double s = hsvColor.s;
     double v = hsvColor.v;
diff --git a/src/color_convert.h b/src/color_convert.h
index f1d48a5bc0..5b2ef251a1 100644
--- a/src/color_convert.h
+++ b/src/color_convert.h
@@ -26,11 +26,10 @@ class TOGGL_INTERNAL_EXPORT ColorConverter {
     static TogglRgbColor GetRgbAdaptiveColor(const std::string &hexColor, TogglAdaptiveColor type);
 
  private:
-    static TogglHsvColor adjustColor(TogglHsvColor hsvColor, TogglAdaptiveColor type);
-    static TogglHsvColor rgbToHsv(TogglRgbColor rgbColor);
+    static TogglHsvColor adjustColor(const TogglHsvColor &hsvColor, TogglAdaptiveColor type);
+    static TogglHsvColor rgbToHsv(const TogglRgbColor &rgbColor);
     static TogglRgbColor hexToRgb(std::string hex);
-    static std::string rgbToHex(TogglRgbColor rbg);
-    static TogglRgbColor hsvToRgb(TogglHsvColor hsvColor);
+    static TogglRgbColor hsvToRgb(const TogglHsvColor &hsvColor);
 };
 
 }
diff --git a/src/context.cc b/src/context.cc
index f985748fd0..7469716b18 100644
--- a/src/context.cc
+++ b/src/context.cc
@@ -666,7 +666,7 @@ void Context::updateUI(const UIElements &what) {
 
         if (what.display_time_entries && user_) {
             if (what.open_time_entry_list) {
-                time_entry_editor_guid_ = "";
+                time_entry_editor_guid_.clear();
             }
 
             // Get a sorted list of time entries
@@ -683,7 +683,7 @@ void Context::updateUI(const UIElements &what) {
             std::map<std::string, Poco::UInt64> group_header_id;
             std::map<std::string, std::vector<Poco::UInt64> > group_items;
 
-            for (unsigned int i = 0; i < time_entries.size(); i++) {
+            for (size_t i = 0; i < time_entries.size(); i++) {
                 TimeEntry *te = time_entries[i];
 
                 std::string date_header =
@@ -715,7 +715,7 @@ void Context::updateUI(const UIElements &what) {
             }
 
             // Assign the date durations we calculated previously
-            for (unsigned int i = 0; i < time_entries.size(); i++) {
+            for (size_t i = 0; i < time_entries.size(); i++) {
                 TimeEntry *te = time_entries[i];
 
                 // Dont render running entry in list,
@@ -734,7 +734,7 @@ void Context::updateUI(const UIElements &what) {
                         if (group_header_id[view.GroupName] == i) {
                             // If Group open add all entries in group
                             if (entry_groups[view.GroupName]) {
-                                for (unsigned int j = 0; j < group_items[view.GroupName].size(); j++) {
+                                for (size_t j = 0; j < group_items[view.GroupName].size(); j++) {
                                     TimeEntry *group_entry =
                                         time_entries[group_items[view.GroupName][j]];
 
@@ -872,18 +872,19 @@ void Context::updateUI(const UIElements &what) {
             std::sort(time_entries.begin(), time_entries.end(),
                       CompareByStart);
 
+            Poco::LocalDateTime tl = UI()->TimelineDateAt();
             Poco::LocalDateTime datetime(
-                UI()->TimelineDateAt().year(),
-                UI()->TimelineDateAt().month(),
-                UI()->TimelineDateAt().day());
-            int tzd = datetime.tzd();
+                tl.year(),
+                tl.month(),
+                tl.day());
+            time_t tzd = datetime.tzd();
 
             // Get all entires in this day (no chunk, no overlap)
             time_t start_day = datetime.timestamp().epochTime() - tzd;
             time_t end_day = start_day + 86400; // one day
 
             // Collect the time entries into a list
-            for (unsigned int i = 0; i < time_entries.size(); i++) {
+            for (size_t i = 0; i < time_entries.size(); i++) {
                 TimeEntry *te = time_entries[i];
                 if (te->Duration() < 0) {
                     // Don't account running entries
@@ -1836,8 +1837,8 @@ void Context::onTimelineUpdateServerSettings(Poco::Util::TimerTask&) {  // NOLIN
     HTTPRequest req;
     req.host = urls::TimelineUpload();
     req.relative_url = "/api/v8/timeline_settings";
-    req.payload = json;
-    req.basic_auth_username = apitoken;
+    req.payload = std::move(json);
+    req.basic_auth_username = std::move(apitoken);
     req.basic_auth_password = "api_token";
 
     HTTPResponse resp = TogglClient::GetInstance().Post(req);
@@ -1941,8 +1942,8 @@ void Context::onSendFeedback(Poco::Util::TimerTask&) {  // NOLINT
     HTTPRequest req;
     req.host = urls::API();
     req.relative_url ="/api/v8/feedback/web";
-    req.basic_auth_username = api_token_value;
-    req.basic_auth_password = api_token_name;
+    req.basic_auth_username = std::move(api_token_value);
+    req.basic_auth_password = std::move(api_token_name);
     req.form = &form;
 
     HTTPResponse resp = TogglClient::GetInstance().Post(req);
@@ -2495,7 +2496,7 @@ void Context::SetNeedEnableSSO(const std::string &code) {
 
 void Context::ResetEnableSSO() {
     need_enable_SSO = false;
-    sso_confirmation_code = "";
+    sso_confirmation_code.clear();
 }
 
 void Context::LoginSSO(const std::string &api_token) {
@@ -3129,8 +3130,8 @@ void Context::OpenTimeEntryEditor(
     if (time_entry_editor_guid_ == te->GUID()) {
         render.open_time_entry_editor = false;
         render.display_time_entry_editor = false;
-        render.time_entry_editor_guid = "";
-        render.time_entry_editor_field = "";
+        render.time_entry_editor_guid.clear();
+        render.time_entry_editor_field.clear();
 
         render.open_time_entry_list = true;
         render.display_time_entries = true;
@@ -3588,7 +3589,7 @@ error Context::SetTimeEntryStart(
     if (dt.utcTime() > now.utcTime()) {
         Poco::LocalDateTime new_date =
             dt - Poco::Timespan(1 * Poco::Timespan::DAYS);
-        dt = new_date;
+        dt = std::move(new_date);
     }
 
     std::string s = Poco::DateTimeFormatter::format(
@@ -3900,7 +3901,7 @@ error Context::DiscardTimeAt(
         render.open_time_entry_editor = true;
         render.display_time_entry_editor = true;
         render.time_entry_editor_guid = split->GUID();
-        render.time_entry_editor_field = "";
+        render.time_entry_editor_field.clear();
         updateUI(render);
     }
 
@@ -4553,7 +4554,7 @@ error Context::OpenReportsInBrowser() {
     req.host = urls::API();
     req.relative_url = "/api/v8/desktop_login_tokens";
     req.payload = "{}";
-    req.basic_auth_username = apitoken;
+    req.basic_auth_username = std::move(apitoken);
     req.basic_auth_password = "api_token";
 
     HTTPResponse resp = TogglClient::GetInstance().Post(req);
@@ -5091,7 +5092,7 @@ void Context::uiUpdaterActivity() {
             updateUI(render);
         }
 
-        running_time = date_duration;
+        running_time = std::move(date_duration);
     }
 }
 
@@ -5305,7 +5306,7 @@ void Context::onLoadMore(Poco::Util::TimerTask&) {
         HTTPRequest req;
         req.host = urls::API();
         req.relative_url = ss.str();
-        req.basic_auth_username = api_token;
+        req.basic_auth_username = std::move(api_token);
         req.basic_auth_password = "api_token";
 
         HTTPResponse resp = TogglClient::GetInstance().Get(req);
@@ -5604,10 +5605,10 @@ error Context::pushBatchedChanges(
             lastRequestUUID_ = Poco::UUIDGenerator().createOne().toString();
 
             HTTPRequest req;
-            req.payload = payload;
+            req.payload = std::move(payload);
             req.host = urls::SyncAPI();
             req.relative_url = "/push/" + lastRequestUUID_;
-            req.basic_auth_username = api_token;
+            req.basic_auth_username = std::move(api_token);
             req.basic_auth_password = "api_token";
 
             auto response = TogglClient::GetInstance().Post(req);
@@ -5956,7 +5957,7 @@ error Context::pushEntries(
         HTTPResponse resp;
 
         if ((*it)->NeedsDELETE()) {
-            req.payload = "";
+            req.payload.clear();
             resp = TogglClient::GetInstance().Delete(req);
         } else if ((*it)->ID()) {
             resp = TogglClient::GetInstance().Put(req);
@@ -6180,7 +6181,7 @@ error Context::pullWorkspaces() {
         HTTPRequest req;
         req.host = urls::API();
         req.relative_url = "/api/v9/me/workspaces";
-        req.basic_auth_username = api_token;
+        req.basic_auth_username = std::move(api_token);
         req.basic_auth_password = "api_token";
 
         HTTPResponse resp = TogglClient::GetInstance().Get(req);
@@ -6267,7 +6268,7 @@ error Context::pullWorkspacePreferences(
         HTTPRequest req;
         req.host = urls::API();
         req.relative_url = ss.str();
-        req.basic_auth_username = api_token;
+        req.basic_auth_username = std::move(api_token);
         req.basic_auth_password = "api_token";
 
         HTTPResponse resp = TogglClient::GetInstance().Get(req);
@@ -6302,7 +6303,7 @@ error Context::pullUserPreferences() {
         HTTPRequest req;
         req.host = urls::API();
         req.relative_url = "/api/v9/me/preferences/desktop";
-        req.basic_auth_username = api_token;
+        req.basic_auth_username = std::move(api_token);
         req.basic_auth_password = "api_token";
 
         HTTPResponse resp = TogglClient::GetInstance().Get(req);
@@ -6737,7 +6738,7 @@ error Context::ToSAccept() {
         HTTPRequest req;
         req.host = urls::API();
         req.relative_url = "/api/v9/me/accept_tos";
-        req.basic_auth_username = api_token;
+        req.basic_auth_username = std::move(api_token);
         req.basic_auth_password = "api_token";
 
         HTTPResponse resp = TogglClient::GetInstance().Post(req);
@@ -6759,7 +6760,7 @@ error Context::ToSAccept() {
     return noError;
 }
 
-error Context::ToggleEntriesGroup(std::string name) {
+error Context::ToggleEntriesGroup(const std::string& name) {
     entry_groups[name] = !entry_groups[name];
     OpenTimeEntryList();
     return noError;
@@ -6838,7 +6839,7 @@ void Context::collectPushableModels(
 
 void on_websocket_message(
     void *context,
-    std::string json) {
+    const std::string json) {
 
     poco_check_ptr(context);
 
diff --git a/src/context.h b/src/context.h
index 3a07ffcff8..5eb65e2d3d 100644
--- a/src/context.h
+++ b/src/context.h
@@ -65,8 +65,8 @@ class TOGGL_INTERNAL_EXPORT UIElements {
     , open_time_entry_editor(false)
     , display_autotracker_rules(false)
     , display_settings(false)
-    , time_entry_editor_guid("")
-    , time_entry_editor_field("")
+    , time_entry_editor_guid()
+    , time_entry_editor_field()
     , display_unsynced_items(false)
     , display_timeline(false)
     , open_timeline(false) {}
@@ -568,7 +568,7 @@ class TOGGL_INTERNAL_EXPORT Context : public TimelineDatasource {
         const int64_t promotion_response);
 
     error ToggleEntriesGroup(
-        std::string name);
+        const std::string& name);
 
     error AsyncPullCountries();
     error PullCountries();
@@ -903,7 +903,7 @@ class TOGGL_INTERNAL_EXPORT Context : public TimelineDatasource {
 };
 void on_websocket_message(
     void *context,
-    std::string json);
+    const std::string json);
 
 }  // namespace toggl
 
diff --git a/src/database/database.cc b/src/database/database.cc
index df801f5dd1..fc5546e0f3 100644
--- a/src/database/database.cc
+++ b/src/database/database.cc
@@ -992,7 +992,7 @@ error Database::Trim(const std::string &text, std::string *result) {
         poco_check_ptr(session_);
         poco_check_ptr(result);
 
-        *result = "";
+        result->clear();
 
         *session_ <<
                   "select trim(:text) limit 1",
@@ -3501,7 +3501,7 @@ error Database::CurrentAPIToken(
         poco_check_ptr(session_);
         Poco::Mutex::ScopedLock lock(session_m_);
 
-        *token = "";
+        token->clear();
         *uid = 0;
 
         *session_ <<
@@ -3816,7 +3816,7 @@ error Database::String(
         *session_ << sql,
         into(value),
         now;
-        *result = value;
+        *result = std::move(value);
     } catch(const Poco::Exception& exc) {
         return exc.displayText();
     } catch(const std::exception& ex) {
diff --git a/src/feedback.h b/src/feedback.h
index e823c8d771..c025245f48 100644
--- a/src/feedback.h
+++ b/src/feedback.h
@@ -13,9 +13,9 @@ namespace toggl {
 class TOGGL_INTERNAL_EXPORT Feedback {
  public:
     Feedback()
-        : subject_("")
-    , details_("")
-    , attachment_path_("") {}
+        : subject_()
+    , details_()
+    , attachment_path_() {}
     ~Feedback() {}
 
     toggl::error Validate() const;
diff --git a/src/get_focused_window_windows.cc b/src/get_focused_window_windows.cc
index 9788474056..c1765c0eff 100644
--- a/src/get_focused_window_windows.cc
+++ b/src/get_focused_window_windows.cc
@@ -17,8 +17,8 @@ int getFocusedWindowInfo(
     std::string *title,
     std::string *filename,
     bool *idle) {
-    *title = "";
-    *filename = "";
+    title->clear();
+    filename->clear();
     *idle = false;
 
     // get window handle
@@ -76,7 +76,7 @@ int getFocusedWindowInfo(
         Poco::UnicodeConverter::toUTF8(buf, utf8);
 #endif
 
-        *title = utf8;
+        *title = std::move(utf8);
     }
 
     return 0;
diff --git a/src/gui.cc b/src/gui.cc
index b5c6a472ac..8cdb39a137 100644
--- a/src/gui.cc
+++ b/src/gui.cc
@@ -411,7 +411,7 @@ void GUI::DisplayTimeEntryList(const bool open,
 
             // Get render list from last 9 days at the first launch
             time_t last9Days = time(nullptr) - 9 * 86400;
-            for (auto it = list.begin(); it != list.end(); it++) {
+            for (auto it = list.begin(); it != list.end(); ++it) {
                 auto timeEntry = *it;
                 if (timeEntry.Started >= last9Days) {
                     renderList.push_back(timeEntry);
@@ -461,13 +461,13 @@ void GUI::DisplayTimeline(const bool open,
         TimelineDateAt().year(),
         TimelineDateAt().month(),
         TimelineDateAt().day());
-    int tzd = datetime.tzd();
+    time_t tzd = datetime.tzd();
 
     // Get all entires in this day (no chunk, no overlap)
     TogglTimeEntryView *first_entry = nullptr;
     time_t start_day = datetime.timestamp().epochTime() - tzd;
     time_t end_day = start_day + 86400; // one day
-    for (unsigned int i = 0; i < entries_list.size(); i++) {
+    for (size_t i = 0; i < entries_list.size(); i++) {
         view::TimeEntry te = entries_list.at(i);
         TogglTimeEntryView *item = time_entry_view_item_init(te);
         time_t start_time_entry = Poco::Timestamp::fromEpochTime(item->Started).epochTime();
diff --git a/src/gui.h b/src/gui.h
index 62b35d6612..429abd416a 100644
--- a/src/gui.h
+++ b/src/gui.h
@@ -28,38 +28,38 @@ class TOGGL_INTERNAL_EXPORT TimeEntry {
     TimeEntry()
         : ID(0)
     , DurationInSeconds(0)
-    , Description("")
-    , ProjectAndTaskLabel("")
-    , TaskLabel("")
-    , ProjectLabel("")
-    , ClientLabel("")
+    , Description()
+    , ProjectAndTaskLabel()
+    , TaskLabel()
+    , ProjectLabel()
+    , ClientLabel()
     , WID(0)
     , PID(0)
     , TID(0)
-    , Duration("")
-    , Color("")
-    , GUID("")
+    , Duration()
+    , Color()
+    , GUID()
     , Billable(false)
-    , Tags("")
+    , Tags()
     , Started(0)
     , Ended(0)
-    , StartTimeString("")
-    , EndTimeString("")
+    , StartTimeString()
+    , EndTimeString()
     , UpdatedAt(0)
     , DurOnly(false)
-    , DateHeader("")
-    , DateDuration("")
+    , DateHeader()
+    , DateDuration()
     , CanAddProjects(false)
     , CanSeeBillable(false)
     , DefaultWID(0)
-    , WorkspaceName("")
+    , WorkspaceName()
     , Unsynced(false)
     , Error(noError)
     , Locked(false)
     , Group(false)
     , GroupOpen(false)
-    , GroupName("")
-    , GroupDuration("")
+    , GroupName()
+    , GroupDuration()
     , GroupItemCount(0)
     , RoundedStart(0)
     , RoundedEnd(0) {}
@@ -118,22 +118,22 @@ class TOGGL_INTERNAL_EXPORT TimeEntry {
 class TOGGL_INTERNAL_EXPORT Autocomplete {
  public:
     Autocomplete()
-        : Text("")
-    , Description("")
-    , ProjectAndTaskLabel("")
-    , TaskLabel("")
-    , ProjectLabel("")
-    , ClientLabel("")
-    , ProjectColor("")
+        : Text()
+    , Description()
+    , ProjectAndTaskLabel()
+    , TaskLabel()
+    , ProjectLabel()
+    , ClientLabel()
+    , ProjectColor()
     , TaskID(0)
     , ProjectID(0)
     , WorkspaceID(0)
     , Type(0)
     , Billable(false)
-    , Tags("")
-    , WorkspaceName("")
+    , Tags()
+    , WorkspaceName()
     , ClientID(0)
-    , ProjectGUID("") {}
+    , ProjectGUID() {}
 
     bool IsTimeEntry() const {
         return kAutocompleteItemTE == Type;
@@ -198,9 +198,9 @@ class TOGGL_INTERNAL_EXPORT Generic {
     Generic()
         : ID(0)
     , WID(0)
-    , GUID("")
-    , Name("")
-    , WorkspaceName("")
+    , GUID()
+    , Name()
+    , WorkspaceName()
     , Premium(false) {}
 
     uint64_t ID;
@@ -231,8 +231,8 @@ class TOGGL_INTERNAL_EXPORT TimelineEvent {
  public:
     TimelineEvent()
         : ID(0)
-    , Title("")
-    , Filename("")
+    , Title()
+    , Filename()
     , StartTime(0)
     , EndTime(0)
     , Idle(false) {}
@@ -251,11 +251,11 @@ class TOGGL_INTERNAL_EXPORT Country {
  public:
     Country()
         : ID(0)
-    , Name("")
+    , Name()
     , VatApplicable(false)
-    , VatRegex("")
-    , VatPercentage("")
-    , Code("") {}
+    , VatRegex()
+    , VatPercentage()
+    , Code() {}
 
     uint64_t ID;
     std::string Name;
@@ -310,7 +310,9 @@ class TOGGL_INTERNAL_EXPORT GUI : public SyncStateMonitor {
     , on_display_help_articles_(nullptr)
     , on_display_project_colors_(nullptr)
     , on_display_countries_(nullptr)
+    , on_display_onboarding_(nullptr)
     , on_continue_sign_in(nullptr)
+    , on_display_login_sso(nullptr)
     , on_display_timeline_ui(nullptr)
     , lastSyncState(-1)
     , lastUnsyncedItemsCount(-1)
@@ -319,7 +321,7 @@ class TOGGL_INTERNAL_EXPORT GUI : public SyncStateMonitor {
     , lastOnlineState(-1)
     , lastErr(noError)
     , isFirstLaunch(true)
-    , time_entry_editor_guid_("")
+    , time_entry_editor_guid_()
     , timeline_date_at_(Poco::LocalDateTime()) {}
 
     ~GUI() {}
@@ -610,7 +612,7 @@ class TOGGL_INTERNAL_EXPORT GUI : public SyncStateMonitor {
     }
 
     void resetTimeEntryGUID() {
-        time_entry_editor_guid_ = "";
+        time_entry_editor_guid_.clear();
     }
 
     void DisplayOnboarding(const OnboardingType onboarding_type);
diff --git a/src/https_client.cc b/src/https_client.cc
index bbed8c21c8..afe7a2b810 100644
--- a/src/https_client.cc
+++ b/src/https_client.cc
@@ -40,7 +40,7 @@
 
 namespace toggl {
 
-void HTTPClient::SetCACertPath(std::string path) {
+void HTTPClient::SetCACertPath(const std::string& path) {
     if (path.compare(Config.CACertPath()) == 0) {
         return;
     }
@@ -72,7 +72,7 @@ void HTTPClient::resetPocoContext() {
         verification_mode, 9, true, "ALL");
     Poco::Net::SSLManager::instance().initializeClient(
         nullptr, acceptCertHandler, _context);
-    context = _context;
+    context = std::move(_context);
 }
 
 void ServerStatus::startStatusCheck() {
@@ -377,10 +377,10 @@ HTTPResponse HTTPClient::makeHttpRequest(
         }
         poco_req.set("User-Agent", HTTPClient::Config.UserAgent());
 
-        Poco::Net::HTTPBasicCredentials cred(
-            req.basic_auth_username, req.basic_auth_password);
         if (!req.basic_auth_username.empty()
                 && !req.basic_auth_password.empty()) {
+            Poco::Net::HTTPBasicCredentials cred(
+                req.basic_auth_username, req.basic_auth_password);
             cred.authenticate(poco_req);
         }
 
@@ -462,7 +462,7 @@ HTTPResponse HTTPClient::makeHttpRequest(
         if (isRedirect(resp.status_code) && response.has("Location")) {
             std::string decoded_url("");
             Poco::URI::decode(response.get("Location"), decoded_url);
-            resp.body = decoded_url;
+            resp.body = std::move(decoded_url);
 
             // Inflate, if gzip was sent
         } else if (response.has("Content-Encoding") &&
@@ -546,7 +546,7 @@ HTTPResponse TogglClient::request(
     if (err != noError) {
         logger().error("Will not connect, because of known bad Toggl status: ", err);
         HTTPResponse resp;
-        resp.err = err;
+        resp.err = std::move(err);
         return resp;
     }
 
diff --git a/src/https_client.h b/src/https_client.h
index 4acba933f5..3d51d16fa0 100644
--- a/src/https_client.h
+++ b/src/https_client.h
@@ -66,13 +66,13 @@ class TOGGL_INTERNAL_EXPORT ServerStatus {
 class TOGGL_INTERNAL_EXPORT HTTPClientConfig {
  public:
     HTTPClientConfig()
-        : AppName("")
-    , AppVersion("")
+        : AppName()
+    , AppVersion()
     , UseProxy(false)
     , ProxySettings(Proxy())
     , AutodetectProxy(true)
     , ignoreCert(false)
-    , caCertPath("") {}
+    , caCertPath() {}
     ~HTTPClientConfig() {}
 
     std::string AppName;
@@ -93,7 +93,7 @@ class TOGGL_INTERNAL_EXPORT HTTPClientConfig {
     std::string CACertPath() {
         return caCertPath;
     };
-    void SetCACertPath(std::string path) {
+    void SetCACertPath(const std::string& path) {
         caCertPath = path;
     }
     void SetIgnoreCert(bool ignore) {
@@ -108,12 +108,12 @@ class TOGGL_INTERNAL_EXPORT HTTPClientConfig {
 class TOGGL_INTERNAL_EXPORT HTTPRequest {
  public:
     HTTPRequest()
-        : method("")
-    , host("")
-    , relative_url("")
-    , payload("")
-    , basic_auth_username("")
-    , basic_auth_password("")
+        : method()
+    , host()
+    , relative_url()
+    , payload()
+    , basic_auth_username()
+    , basic_auth_password()
     , form(nullptr)
     , query(nullptr)
     , timeout_seconds(kHTTPClientTimeoutSeconds) {}
@@ -133,7 +133,7 @@ class TOGGL_INTERNAL_EXPORT HTTPRequest {
 class TOGGL_INTERNAL_EXPORT HTTPResponse {
  public:
     HTTPResponse()
-        : body("")
+        : body()
     , err(noError)
     , status_code(0) {}
     virtual ~HTTPResponse() {}
@@ -162,7 +162,7 @@ class TOGGL_INTERNAL_EXPORT HTTPClient {
 
     static HTTPClientConfig Config;
 
-    void SetCACertPath(std::string path);
+    void SetCACertPath(const std::string& path);
     void SetIgnoreCert(bool ignore);
 
     static error StatusCodeToError(const Poco::Int64 status_code);
diff --git a/src/model/alpha_features.cpp b/src/model/alpha_features.cpp
index 8ae8462d15..c83dfdfc32 100644
--- a/src/model/alpha_features.cpp
+++ b/src/model/alpha_features.cpp
@@ -15,7 +15,7 @@ namespace toggl {
         isTimelineUiEnabled_ = false;
     }
 
-    void AlphaFeatures::ReadAlphaFeatures(Json::Value root) {
+    void AlphaFeatures::ReadAlphaFeatures(const Json::Value &root) {
         if (root.isMember("alpha_features")) {
             for (auto i : root["alpha_features"]) {
                 if (i.isMember("code")) {
diff --git a/src/model/alpha_features.h b/src/model/alpha_features.h
index 7f8fc0056f..606ea4c05e 100644
--- a/src/model/alpha_features.h
+++ b/src/model/alpha_features.h
@@ -4,7 +4,7 @@ namespace toggl {
     {
          public:
             AlphaFeatures();
-            void ReadAlphaFeatures(Json::Value root);
+            void ReadAlphaFeatures(const Json::Value &root);
             bool IsSyncEnabled();
             bool IsTimelineUiEnabled();
          private:
diff --git a/src/model/settings.h b/src/model/settings.h
index d4aa6f1c6e..ef82fbb299 100644
--- a/src/model/settings.h
+++ b/src/model/settings.h
@@ -35,8 +35,8 @@ class TOGGL_INTERNAL_EXPORT Settings : public BaseModel {
     , remind_fri(true)
     , remind_sat(true)
     , remind_sun(true)
-    , remind_starts("")
-    , remind_ends("")
+    , remind_starts()
+    , remind_ends()
     , autotrack(false)
     , open_editor_on_shortcut(false)
     , has_seen_beta_offering(false)
diff --git a/src/model/time_entry.cc b/src/model/time_entry.cc
index 996835f308..ad484e3423 100644
--- a/src/model/time_entry.cc
+++ b/src/model/time_entry.cc
@@ -323,7 +323,7 @@ void TimeEntry::SetStartString(const std::string &value, bool userModified) {
 }
 
 void TimeEntry::SetDurationUserInput(const std::string &value) {
-    int seconds = Formatter::ParseDurationString(value);
+    time_t seconds = Formatter::ParseDurationString(value);
     if (IsTracking()) {
         time_t now = time(nullptr);
         time_t start = now - seconds;
diff --git a/src/model/user.cc b/src/model/user.cc
index f079e68145..535f73b22d 100644
--- a/src/model/user.cc
+++ b/src/model/user.cc
@@ -1206,7 +1206,7 @@ error User::UserID(
 error User::LoginToken(
     const std::string &json_data_string,
     std::string *result) {
-    *result = "";
+    result->clear();
     Json::Value root;
     Json::Reader reader;
     bool ok = reader.parse(json_data_string, root);
diff --git a/src/onboarding_service.cpp b/src/onboarding_service.cpp
index 48ddb3aad6..1a29708079 100644
--- a/src/onboarding_service.cpp
+++ b/src/onboarding_service.cpp
@@ -216,7 +216,7 @@ bool OnboardingService::hasAtLeastOneTimelineTimeEntryOnCurrentDay() {
     }
 
     // Get current start/end day
-    int tzd = timeline_date_at_.tzd();
+    time_t tzd = timeline_date_at_.tzd();
     time_t start_day = timeline_date_at_.timestamp().epochTime() - tzd;
 
     // Since we don't store the TimeEntry for each particular day
diff --git a/src/proxy.h b/src/proxy.h
index 10fe18c9b9..33202e8218 100644
--- a/src/proxy.h
+++ b/src/proxy.h
@@ -14,10 +14,10 @@ namespace toggl {
 class TOGGL_INTERNAL_EXPORT Proxy {
  public:
     Proxy() :
-    host_(""),
+    host_(),
     port_(0),
-    username_(""),
-    password_("") {}
+    username_(),
+    password_() {}
 
     bool IsConfigured() const;
     bool HasCredentials() const;
diff --git a/src/related_data.cc b/src/related_data.cc
index 51561d916a..8b3b73386e 100644
--- a/src/related_data.cc
+++ b/src/related_data.cc
@@ -70,11 +70,11 @@ error RelatedData::DeleteAutotrackerRule(const Poco::Int64 local_id) {
 
 error RelatedData::UpdateAutotrackerRule(
     const Poco::Int64 local_id,
-    std::string terms,
+    const std::string terms,
     const Poco::UInt64 tid,
     const Poco::UInt64 pid,
-    std::string start_time,
-    std::string end_time,
+    const std::string start_time,
+    const std::string end_time,
     const Poco::UInt8 days_of_week) {
 
     if (!local_id) {
@@ -284,9 +284,9 @@ void RelatedData::timeEntryAutocompleteItems(
         unique_names->insert(text);
 
         view::Autocomplete autocomplete_item;
-        autocomplete_item.Text = text;
-        autocomplete_item.Description = description;
-        autocomplete_item.ProjectAndTaskLabel = project_task_label;
+        autocomplete_item.Text = std::move(text);
+        autocomplete_item.Description = std::move(description);
+        autocomplete_item.ProjectAndTaskLabel = std::move(project_task_label);
         if (p) {
             autocomplete_item.ProjectColor = p->ColorCode();
             autocomplete_item.ProjectID = p->ID();
@@ -366,7 +366,7 @@ void RelatedData::taskAutocompleteItems(
 
         view::Autocomplete autocomplete_item;
         autocomplete_item.Text = t->Name();
-        autocomplete_item.ProjectAndTaskLabel = text;
+        autocomplete_item.ProjectAndTaskLabel = std::move(text);
         autocomplete_item.TaskLabel = t->Name();
         autocomplete_item.TaskID = t->ID();
 
@@ -434,7 +434,7 @@ void RelatedData::projectAutocompleteItems(
 
         view::Autocomplete autocomplete_item;
         autocomplete_item.Text = text;
-        autocomplete_item.ProjectAndTaskLabel = text;
+        autocomplete_item.ProjectAndTaskLabel = std::move(text);
         autocomplete_item.ProjectLabel = p->Name();
         if (c) {
             autocomplete_item.ClientLabel = c->Name();
diff --git a/src/related_data.h b/src/related_data.h
index cf282f3d3c..c151a60be8 100644
--- a/src/related_data.h
+++ b/src/related_data.h
@@ -89,11 +89,11 @@ class TOGGL_INTERNAL_EXPORT RelatedData {
     error DeleteAutotrackerRule(const Poco::Int64 local_id);
     error UpdateAutotrackerRule(
         const Poco::Int64 local_id,
-        std::string terms,
+        const std::string terms,
         const Poco::UInt64 tid,
         const Poco::UInt64 pid,
-        std::string start_time,
-        std::string end_time,
+        const std::string start_time,
+        const std::string end_time,
         const Poco::UInt8 days_of_week);
 
     void TimeEntryAutocompleteItems(std::vector<view::Autocomplete> *) const;
diff --git a/src/timeline_notifications.h b/src/timeline_notifications.h
index b9f9a40dca..a78d03f650 100644
--- a/src/timeline_notifications.h
+++ b/src/timeline_notifications.h
@@ -18,8 +18,8 @@ class TOGGL_INTERNAL_EXPORT TimelineBatch {
  public:
     TimelineBatch()
         : user_id_(0)
-    , api_token_("")
-    , desktop_id_("") {}
+    , api_token_()
+    , desktop_id_() {}
 
     ~TimelineBatch() {}
 
diff --git a/src/timeline_uploader.cc b/src/timeline_uploader.cc
index 117f348d3e..8fbb43ee8c 100644
--- a/src/timeline_uploader.cc
+++ b/src/timeline_uploader.cc
@@ -88,7 +88,7 @@ error TimelineUploader::upload(TimelineBatch *batch) {
     HTTPRequest req;
     req.host = urls::TimelineUpload();
     req.relative_url = "/api/v8/timeline";
-    req.payload = json;
+    req.payload = std::move(json);
     req.basic_auth_username = batch->APIToken();
     req.basic_auth_password = "api_token";
 
diff --git a/src/toggl_api.cc b/src/toggl_api.cc
index c61588b051..7f489d5f41 100644
--- a/src/toggl_api.cc
+++ b/src/toggl_api.cc
@@ -671,7 +671,7 @@ int64_t toggl_timestamp_from_time_string(const char_t *time) {
     if (dt.utcTime() > now.utcTime()) {
         Poco::LocalDateTime new_date =
             dt - Poco::Timespan(1 * Poco::Timespan::DAYS);
-        dt = new_date;
+        dt = std::move(new_date);
     }
 
     return dt.utc().timestamp().epochTime();
@@ -1780,7 +1780,7 @@ void toggl_on_display_login_sso(void *context,
 }
 
 TogglHsvColor toggl_get_adaptive_hsv_color(
-    TogglRgbColor rgbColor,
+    const TogglRgbColor &rgbColor,
     TogglAdaptiveColor type) {
     return toggl::ColorConverter::GetAdaptiveColor(rgbColor, type);
 }
diff --git a/src/toggl_api.h b/src/toggl_api.h
index 5859c294d6..364d68546c 100644
--- a/src/toggl_api.h
+++ b/src/toggl_api.h
@@ -1366,7 +1366,7 @@ extern "C" {
         TogglDisplayLoginSSO cb);
 
     TOGGL_EXPORT TogglHsvColor toggl_get_adaptive_hsv_color(
-       TogglRgbColor rgbColor,
+       const TogglRgbColor &rgbColor,
        TogglAdaptiveColor type);
 
     TOGGL_EXPORT bool_t toggl_get_identity_provider_sso(
diff --git a/src/toggl_api_private.cc b/src/toggl_api_private.cc
index 7165e54f01..dd5904e0a7 100644
--- a/src/toggl_api_private.cc
+++ b/src/toggl_api_private.cc
@@ -216,7 +216,7 @@ void country_list_delete_item(TogglCountryView *first) {
 
 std::string to_string(const char_t *s) {
     if (!s) {
-        return std::string("");
+        return std::string();
     }
 #if defined(_WIN32) || defined(WIN32)
     std::wstring ws(s);
diff --git a/src/util/formatter.cc b/src/util/formatter.cc
index 36b19af2ac..b94b930708 100644
--- a/src/util/formatter.cc
+++ b/src/util/formatter.cc
@@ -193,7 +193,7 @@ bool Formatter::ParseTimeInput(const std::string &input,
     }
 
     // Handle formats: HH:mm, H:mm etc
-    if (value.find(":") != std::string::npos) {
+    if (value.find(':') != std::string::npos) {
         Poco::StringTokenizer tokenizer(value, ":");
         if (2 != tokenizer.count()) {
             return false;
@@ -348,7 +348,7 @@ int Formatter::ParseDurationString(const std::string &value) {
     std::string input = Poco::replace(value, " ", "");
     input = Poco::replace(input, ",", ".");
 
-    if (input.find(":") != std::string::npos) {
+    if (input.find(':') != std::string::npos) {
         int parsed_seconds = 0;
 
         // Parse duration in seconds HH:MM:SS
@@ -374,7 +374,7 @@ int Formatter::ParseDurationString(const std::string &value) {
     int seconds = parseDurationStringHoursMinutesSeconds(&input);
 
     // 15
-    if (input.find(".") == std::string::npos) {
+    if (input.find('.') == std::string::npos) {
         Poco::Int64 minutes = 0;
         if (Poco::NumberParser::tryParse64(input, minutes)) {
             if ((minutes * 60) > kMaxDurationSeconds) {
@@ -607,8 +607,8 @@ bool CompareAutotrackerTitles(const std::string &a, const std::string &b) {
 }
 
 bool CompareAutocompleteItems(
-    view::Autocomplete a,
-    view::Autocomplete b) {
+    const view::Autocomplete& a,
+    const view::Autocomplete& b) {
 
     // Time entries first
     if (a.IsTimeEntry() && !b.IsTimeEntry()) {
@@ -638,8 +638,8 @@ bool CompareAutocompleteItems(
 }
 
 bool CompareStructuredAutocompleteItems(
-    view::Autocomplete a,
-    view::Autocomplete b) {
+    const view::Autocomplete& a,
+    const view::Autocomplete& b) {
 
     if (a.WorkspaceName == b.WorkspaceName) {
         if (a.IsWorkspace() && !b.IsWorkspace()) {
diff --git a/src/util/formatter.h b/src/util/formatter.h
index a9e1171ef0..62f65a405a 100644
--- a/src/util/formatter.h
+++ b/src/util/formatter.h
@@ -144,11 +144,11 @@ bool CompareByStart(
     TimedEvent *a,
     TimedEvent *b);
 bool CompareAutocompleteItems(
-    view::Autocomplete a,
-    view::Autocomplete b);
+    const view::Autocomplete& a,
+    const view::Autocomplete& b);
 bool CompareStructuredAutocompleteItems(
-    view::Autocomplete a,
-    view::Autocomplete b);
+    const view::Autocomplete& a,
+    const view::Autocomplete& b);
 bool CompareWorkspaceByName(
     Workspace *a,
     Workspace *b);
diff --git a/src/util/property.h b/src/util/property.h
index 8bdf549bf8..0806b60514 100644
--- a/src/util/property.h
+++ b/src/util/property.h
@@ -17,10 +17,8 @@ class Property {
 public:
     typedef T value_type;
 
-    Property(const T& value) {
-        current_ = value;
-        previous_ = value;
-    }
+    Property(const T& value) : current_(value), previous_(value) { }
+
     Property(T&& value = T {}) {
         current_ = std::move(value);
         previous_ = current_;
diff --git a/src/websocket_client.cc b/src/websocket_client.cc
index 87f7960695..8b652cade1 100644
--- a/src/websocket_client.cc
+++ b/src/websocket_client.cc
@@ -197,7 +197,7 @@ error WebSocketClient::receiveWebSocketMessage(std::string *message) {
     } catch(const std::string & ex) {
         return error(ex);
     }
-    *message = json;
+    *message = std::move(json);
     return noError;
 }
 
diff --git a/src/websocket_client.h b/src/websocket_client.h
index 1295a19dd9..5af3e1ad47 100644
--- a/src/websocket_client.h
+++ b/src/websocket_client.h
@@ -39,7 +39,7 @@ class TOGGL_INTERNAL_EXPORT WebSocketClient {
     on_websocket_message_(nullptr),
     ctx_(nullptr),
     last_connection_at_(0),
-    api_token_("") {}
+    api_token_() {}
     virtual ~WebSocketClient();
 
     virtual void Start(
diff --git a/src/window_change_recorder.cc b/src/window_change_recorder.cc
index 92a6721e51..019c15e570 100644
--- a/src/window_change_recorder.cc
+++ b/src/window_change_recorder.cc
@@ -94,7 +94,7 @@ void WindowChangeRecorder::inspectFocusedWindow() {
     bool idleChanged = hasIdlenessChanged(idle);
 
     if (idleChanged) {
-        last_autotracker_title_ = "";
+        last_autotracker_title_.clear();
     }
 
     bool windowHasChanged = hasWindowChanged(title, filename);
@@ -128,8 +128,8 @@ void WindowChangeRecorder::inspectFocusedWindow() {
         }
     }
 
-    last_title_ = title;
-    last_filename_ = filename;
+    last_title_ = std::move(title);
+    last_filename_ = std::move(filename);
     last_idle_ = idle;
     last_event_started_at_ = now;
 }
@@ -152,12 +152,6 @@ void WindowChangeRecorder::recordLoop() {
         }
 
         Poco::Thread::sleep(kWindowRecorderSleepMillis);
-
-        if (recording_.isStopped()) {
-            break;
-        }
-
-        Poco::Thread::sleep(kWindowRecorderSleepMillis);
     }
 }
 
diff --git a/src/window_change_recorder.h b/src/window_change_recorder.h
index 562cf39afa..d09d0ab42c 100644
--- a/src/window_change_recorder.h
+++ b/src/window_change_recorder.h
@@ -21,13 +21,14 @@ namespace toggl {
 class TOGGL_INTERNAL_EXPORT WindowChangeRecorder {
  public:
     explicit WindowChangeRecorder(TimelineDatasource *datasource)
-        : last_title_("")
-    , last_filename_("")
+        : last_title_()
+    , last_filename_()
     , last_event_started_at_(0)
+    , current_app_started_at_(0)
     , last_idle_(false)
     , timeline_datasource_(datasource)
     , recording_(this, &WindowChangeRecorder::recordLoop)
-    , last_autotracker_title_("")
+    , last_autotracker_title_()
     , shutdown_(false)
     , isLocked_(false)
     , isSleeping_(false)