diff --git a/meson.build b/meson.build
index fef3652bd..2502152f9 100644
--- a/meson.build
+++ b/meson.build
@@ -63,6 +63,8 @@ if is_debug
   add_project_arguments([
     '-ggdb3',
     '-Wunused',
+    '-Wall',
+    '-Wextra',
   ], language: 'c')
 endif
 
diff --git a/src/command/cmd_ac.c b/src/command/cmd_ac.c
index d353abcfb..03c940f24 100644
--- a/src/command/cmd_ac.c
+++ b/src/command/cmd_ac.c
@@ -1767,7 +1767,7 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
                                  "/history", "/vercheck", "/privileges", "/wrap",
                                  "/carbons", "/slashguard", "/mam", "/silence" };
 
-    for (int i = 0; i < ARRAY_SIZE(boolean_choices); i++) {
+    for (size_t i = 0; i < ARRAY_SIZE(boolean_choices); i++) {
         result = autocomplete_param_with_func(input, boolean_choices[i], prefs_autocomplete_boolean_choice, previous, NULL);
         if (result) {
             return result;
@@ -1784,7 +1784,7 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
 
             // Remove quote character before and after names when doing autocomplete
             char* unquoted = strip_arg_quotes(input);
-            for (int i = 0; i < ARRAY_SIZE(nick_choices); i++) {
+            for (size_t i = 0; i < ARRAY_SIZE(nick_choices); i++) {
                 result = autocomplete_param_with_ac(unquoted, nick_choices[i], nick_ac, TRUE, previous);
                 if (result) {
                     free(unquoted);
@@ -1799,7 +1799,7 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
         gchar* contact_choices[] = { "/msg", "/info" };
         // Remove quote character before and after names when doing autocomplete
         char* unquoted = strip_arg_quotes(input);
-        for (int i = 0; i < ARRAY_SIZE(contact_choices); i++) {
+        for (size_t i = 0; i < ARRAY_SIZE(contact_choices); i++) {
             result = autocomplete_param_with_func(unquoted, contact_choices[i], roster_contact_autocomplete, previous, NULL);
             if (result) {
                 free(unquoted);
@@ -1814,7 +1814,7 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
         free(unquoted);
 
         gchar* resource_choices[] = { "/caps", "/ping" };
-        for (int i = 0; i < ARRAY_SIZE(resource_choices); i++) {
+        for (size_t i = 0; i < ARRAY_SIZE(resource_choices); i++) {
             result = autocomplete_param_with_func(input, resource_choices[i], roster_fulljid_autocomplete, previous, NULL);
             if (result) {
                 return result;
@@ -1823,7 +1823,7 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
     }
 
     gchar* invite_choices[] = { "/join" };
-    for (int i = 0; i < ARRAY_SIZE(invite_choices); i++) {
+    for (size_t i = 0; i < ARRAY_SIZE(invite_choices); i++) {
         result = autocomplete_param_with_func(input, invite_choices[i], muc_invites_find, previous, NULL);
         if (result) {
             return result;
@@ -1843,7 +1843,7 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
         { "/inputwin", winpos_ac },
     };
 
-    for (int i = 0; i < ARRAY_SIZE(ac_cmds); i++) {
+    for (size_t i = 0; i < ARRAY_SIZE(ac_cmds); i++) {
         result = autocomplete_param_with_ac(input, ac_cmds[i].cmd, ac_cmds[i].completer, TRUE, previous);
         if (result) {
             return result;
@@ -1863,7 +1863,8 @@ _cmd_ac_complete_params(ProfWin* window, const char* const input, gboolean previ
     }
     parsed[i] = '\0';
 
-    char* (*ac_func)(ProfWin*, const char* const, gboolean) = g_hash_table_lookup(ac_funcs, parsed);
+    char* (*ac_func)(ProfWin*, const char* const, gboolean) = (char* (*)(ProfWin*, const char* const, gboolean))g_hash_table_lookup(ac_funcs, parsed);
+
     if (ac_func) {
         result = ac_func(window, input, previous);
         if (result) {
@@ -1932,7 +1933,7 @@ _who_autocomplete(ProfWin* window, const char* const input, gboolean previous)
                                         "/who chat", "/who away", "/who xa", "/who dnd", "/who available",
                                         "/who unavailable" };
 
-            for (int i = 0; i < ARRAY_SIZE(group_commands); i++) {
+            for (size_t i = 0; i < ARRAY_SIZE(group_commands); i++) {
                 result = autocomplete_param_with_func(input, group_commands[i], roster_group_autocomplete, previous, NULL);
                 if (result) {
                     return result;
@@ -2254,7 +2255,7 @@ _notify_autocomplete(ProfWin* window, const char* const input, gboolean previous
 
     gchar* boolean_choices1[] = { "/notify room current", "/notify chat current", "/notify typing current",
                                   "/notify room text", "/notify chat text", "/notify room offline" };
-    for (int i = 0; i < ARRAY_SIZE(boolean_choices1); i++) {
+    for (size_t i = 0; i < ARRAY_SIZE(boolean_choices1); i++) {
         result = autocomplete_param_with_func(input, boolean_choices1[i], prefs_autocomplete_boolean_choice, previous, NULL);
         if (result) {
             return result;
@@ -2287,7 +2288,7 @@ _notify_autocomplete(ProfWin* window, const char* const input, gboolean previous
     }
 
     gchar* boolean_choices2[] = { "/notify invite", "/notify sub", "/notify mention", "/notify trigger" };
-    for (int i = 0; i < ARRAY_SIZE(boolean_choices2); i++) {
+    for (size_t i = 0; i < ARRAY_SIZE(boolean_choices2); i++) {
         result = autocomplete_param_with_func(input, boolean_choices2[i], prefs_autocomplete_boolean_choice, previous, NULL);
         if (result) {
             return result;
@@ -3733,7 +3734,7 @@ _account_autocomplete(ProfWin* window, const char* const input, gboolean previou
                                 "/account disable", "/account rename", "/account clear", "/account remove",
                                 "/account default set" };
 
-    for (int i = 0; i < ARRAY_SIZE(account_choice); i++) {
+    for (size_t i = 0; i < ARRAY_SIZE(account_choice); i++) {
         found = autocomplete_param_with_func(input, account_choice[i], accounts_find_all, previous, NULL);
         if (found) {
             return found;
@@ -4274,7 +4275,7 @@ _vcard_autocomplete(ProfWin* window, const char* const input, gboolean previous)
         gboolean is_num = TRUE;
 
         if (num_args >= 2) {
-            for (int i = 0; i < strlen(args[1]); i++) {
+            for (size_t i = 0; i < strlen(args[1]); i++) {
                 if (!isdigit((int)args[1][i])) {
                     is_num = FALSE;
                     break;
diff --git a/src/command/cmd_defs.c b/src/command/cmd_defs.c
index f864f38de..0a9c34ec6 100644
--- a/src/command/cmd_defs.c
+++ b/src/command/cmd_defs.c
@@ -2796,7 +2796,7 @@ _cmd_index(const Command* cmd)
     g_string_free(index_source, TRUE);
 
     GString* index = g_string_new("");
-    for (int i = 0; i < g_strv_length(tokens); i++) {
+    for (guint i = 0; i < g_strv_length(tokens); i++) {
         index = g_string_append(index, tokens[i]);
         index = g_string_append(index, " ");
     }
diff --git a/src/command/cmd_funcs.c b/src/command/cmd_funcs.c
index 9946f68e2..cc6e10f8b 100644
--- a/src/command/cmd_funcs.c
+++ b/src/command/cmd_funcs.c
@@ -1084,7 +1084,7 @@ _writecsv(int fd, const char* const str)
 
     auto_char char* s = malloc(2 * len * sizeof(char));
     char* c = s;
-    for (int i = 0; i < strlen(str); i++) {
+    for (size_t i = 0; i < strlen(str); i++) {
         if (str[i] != '"')
             *c++ = str[i];
         else {
@@ -1387,7 +1387,7 @@ cmd_close(ProfWin* window, const char* const command, gchar** args)
     gboolean is_num = TRUE;
     int index = 0;
     if (args[0] != NULL) {
-        for (int i = 0; i < strlen(args[0]); i++) {
+        for (size_t i = 0; i < strlen(args[0]); i++) {
             if (!isdigit((int)args[0][i])) {
                 is_num = FALSE;
                 break;
@@ -1474,7 +1474,7 @@ gboolean
 cmd_win(ProfWin* window, const char* const command, gchar** args)
 {
     gboolean is_num = TRUE;
-    for (int i = 0; i < strlen(args[0]); i++) {
+    for (size_t i = 0; i < strlen(args[0]); i++) {
         if (!isdigit((int)args[0][i])) {
             is_num = FALSE;
             break;
@@ -9983,7 +9983,7 @@ cmd_vcard_set(ProfWin* window, const char* const command, gchar** args)
     }
 
     gboolean is_num = TRUE;
-    for (int i = 0; i < strlen(key); i++) {
+    for (size_t i = 0; i < strlen(key); i++) {
         if (!isdigit((int)key[i])) {
             is_num = FALSE;
             break;
diff --git a/src/config/color.c b/src/config/color.c
index 1912352a3..234a5e55e 100644
--- a/src/config/color.c
+++ b/src/config/color.c
@@ -344,7 +344,7 @@ color_distance(const struct color_def* a, const struct color_def* b)
 static int
 find_closest_col(int h, int s, int l)
 {
-    struct color_def a = { h, s, l };
+    struct color_def a = { h, s, l, NULL };
     int min = 0;
     int dmin = color_distance(&a, &color_names[0]);
 
@@ -369,7 +369,7 @@ find_col(const char* col_name, int n)
      * blue.
      */
 
-    if (n >= sizeof(name)) {
+    if (n >= (int)sizeof(name)) {
         /* truncate */
         log_error("Color: <%s,%d> bigger than %zu", col_name, n, sizeof(name));
         n = sizeof(name) - 1;
diff --git a/src/config/preferences.c b/src/config/preferences.c
index 22bf02037..9b6a9dd50 100644
--- a/src/config/preferences.c
+++ b/src/config/preferences.c
@@ -253,7 +253,7 @@ _prefs_load(void)
     gsize len = 0;
     auto_gcharv gchar** triggers = g_key_file_get_string_list(prefs, PREF_GROUP_NOTIFICATIONS, "room.trigger.list", &len, NULL);
 
-    for (int i = 0; i < len; i++) {
+    for (gsize i = 0; i < len; i++) {
         autocomplete_add(room_trigger_ac, triggers[i]);
     }
 }
@@ -418,7 +418,7 @@ prefs_message_get_triggers(const char* const message)
     gsize len = 0;
     auto_gcharv gchar** triggers = g_key_file_get_string_list(prefs, PREF_GROUP_NOTIFICATIONS, "room.trigger.list", &len, NULL);
 
-    for (int i = 0; i < len; i++) {
+    for (gsize i = 0; i < len; i++) {
         auto_gchar gchar* trigger_lower = g_utf8_strdown(triggers[i], -1);
         if (g_strrstr(message_lower, trigger_lower)) {
             result = g_list_append(result, strdup(triggers[i]));
@@ -1392,7 +1392,7 @@ prefs_get_room_notify_triggers(void)
     gsize len = 0;
     auto_gcharv gchar** triggers = g_key_file_get_string_list(prefs, PREF_GROUP_NOTIFICATIONS, "room.trigger.list", &len, NULL);
 
-    for (int i = 0; i < len; i++) {
+    for (gsize i = 0; i < len; i++) {
         result = g_list_append(result, strdup(triggers[i]));
     }
 
@@ -1739,7 +1739,7 @@ prefs_get_aliases(void)
         gsize len;
         auto_gcharv gchar** keys = g_key_file_get_keys(prefs, PREF_GROUP_ALIAS, &len, NULL);
 
-        for (int i = 0; i < len; i++) {
+        for (gsize i = 0; i < len; i++) {
             char* name = keys[i];
             auto_gchar gchar* value = g_key_file_get_string(prefs, PREF_GROUP_ALIAS, name, NULL);
 
diff --git a/src/config/tlscerts.c b/src/config/tlscerts.c
index 9a622e66e..b1a4823af 100644
--- a/src/config/tlscerts.c
+++ b/src/config/tlscerts.c
@@ -82,7 +82,7 @@ tlscerts_init(void)
     gsize len = 0;
     auto_gcharv gchar** groups = g_key_file_get_groups(tlscerts, &len);
 
-    for (int i = 0; i < g_strv_length(groups); i++) {
+    for (guint i = 0; i < g_strv_length(groups); i++) {
         autocomplete_add(certs_ac, groups[i]);
     }
 
diff --git a/src/main.c b/src/main.c
index 4ef8bd0d7..03ae9a85c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -78,7 +78,7 @@ main(int argc, char** argv)
 
     GOptionEntry entries[] = {
         { "version", 'v', 0, G_OPTION_ARG_NONE, &version, "Show version information", NULL },
-        { "account", 'a', 0, G_OPTION_ARG_STRING, &account_name, "Auto connect to an account on startup" },
+        { "account", 'a', 0, G_OPTION_ARG_STRING, &account_name, "Auto connect to an account on startup", NULL },
         { "log", 'l', 0, G_OPTION_ARG_STRING, &log, "Set logging levels, DEBUG, INFO, WARN (default), ERROR", "LEVEL" },
         { "config", 'c', 0, G_OPTION_ARG_STRING, &config_file, "Use an alternative configuration file", NULL },
         { "logfile", 'f', 0, G_OPTION_ARG_STRING, &log_file, "Specify log file", NULL },
diff --git a/src/omemo/omemo.c b/src/omemo/omemo.c
index f46fbf957..7da6e4f5d 100644
--- a/src/omemo/omemo.c
+++ b/src/omemo/omemo.c
@@ -773,7 +773,7 @@ omemo_on_message_send(ProfWin* win, const char* const message, gboolean request_
             // <https://xmpp.org/extensions/xep-0384.html#encrypt>).
             // Yourself as recipients in case of MUC
             if (equals_our_barejid(recipients_iter->data)) {
-                if (GPOINTER_TO_INT(device_ids_iter->data) == omemo_ctx.device_id) {
+                if ((uint32_t)GPOINTER_TO_INT(device_ids_iter->data) == omemo_ctx.device_id) {
                     log_debug("[OMEMO][SEND] Skipping %d (my device) ", GPOINTER_TO_INT(device_ids_iter->data));
                     continue;
                 }
@@ -832,7 +832,7 @@ omemo_on_message_send(ProfWin* win, const char* const message, gboolean request_
             log_debug("[OMEMO][SEND][Sender] Sending to device %d for %s ", address.device_id, address.name);
             // Don't encrypt for this device (according to
             // <https://xmpp.org/extensions/xep-0384.html#encrypt>).
-            if (address.device_id == omemo_ctx.device_id) {
+            if ((uint32_t)address.device_id == omemo_ctx.device_id) {
                 continue;
             }
 
@@ -1030,7 +1030,7 @@ omemo_format_fingerprint(const char* const fingerprint)
 {
     char* output = malloc(strlen(fingerprint) + strlen(fingerprint) / 8);
 
-    int i, j;
+    size_t i, j;
     for (i = 0, j = 0; i < strlen(fingerprint); i++) {
         if (i > 0 && i % 8 == 0) {
             output[j++] = '-';
@@ -1117,7 +1117,7 @@ omemo_is_trusted_identity(const char* const jid, const char* const fingerprint)
 static char*
 _omemo_fingerprint(ec_public_key* identity, gboolean formatted)
 {
-    int i;
+    size_t i;
     signal_buffer* identity_public_key;
 
     ec_public_key_serialize(&identity_public_key, identity);
@@ -1161,8 +1161,8 @@ _omemo_fingerprint_decode(const char* const fingerprint, size_t* len)
 {
     unsigned char* output = malloc(strlen(fingerprint) / 2 + 1);
 
-    int i;
-    int j;
+    size_t i;
+    size_t j;
     for (i = 0, j = 0; i < strlen(fingerprint);) {
         if (!g_ascii_isxdigit(fingerprint[i])) {
             i++;
@@ -1724,7 +1724,7 @@ _bytes_from_hex(const char* hex, size_t hex_size,
 
     memset(bytes, 0, bytes_size);
 
-    for (int i = 0; (i < hex_size) && (i / 2 < bytes_size); i += 2) {
+    for (size_t i = 0; (i < hex_size) && (i / 2 < bytes_size); i += 2) {
         b0 = ((unsigned char)hex[i + 0] & 0x1f) ^ 0x10;
         b1 = ((unsigned char)hex[i + 1] & 0x1f) ^ 0x10;
 
diff --git a/src/pgp/gpg.c b/src/pgp/gpg.c
index 43cd65ddf..064492bfc 100644
--- a/src/pgp/gpg.c
+++ b/src/pgp/gpg.c
@@ -87,7 +87,7 @@ _p_gpg_free_pubkeyid(ProfPGPPubKeyId* pubkeyid)
     free(pubkeyid);
 }
 
-static gpgme_error_t*
+static gpgme_error_t
 _p_gpg_passphrase_cb(void* hook, const char* uid_hint, const char* passphrase_info, int prev_was_bad, int fd)
 {
     if (passphrase) {
@@ -109,7 +109,7 @@ _p_gpg_passphrase_cb(void* hook, const char* uid_hint, const char* passphrase_in
         gpgme_io_write(fd, passphrase_attempt, strlen(passphrase_attempt));
     }
 
-    return 0;
+    return GPG_ERR_NO_ERROR;
 }
 
 static void
@@ -180,7 +180,7 @@ p_gpg_on_connect(const char* const barejid)
         return;
     }
 
-    for (int i = 0; i < len; i++) {
+    for (gsize i = 0; i < len; i++) {
         GError* gerr = NULL;
         gchar* jid = jids[i];
         auto_gchar gchar* keyid = g_key_file_get_string(pubkeyfile, jid, "keyid", &gerr);
diff --git a/src/plugins/plugins.c b/src/plugins/plugins.c
index 7e867cd18..52ec9db8c 100644
--- a/src/plugins/plugins.c
+++ b/src/plugins/plugins.c
@@ -126,7 +126,7 @@ plugins_init(void)
     if (!plugins_pref) {
         return;
     }
-    for (int i = 0; i < g_strv_length(plugins_pref); i++) {
+    for (guint i = 0; i < g_strv_length(plugins_pref); i++) {
         gboolean loaded = FALSE;
         gchar* filename = plugins_pref[i];
 #ifdef HAVE_PYTHON
diff --git a/src/plugins/python_api.c b/src/plugins/python_api.c
index c8a04a8fa..572226876 100644
--- a/src/plugins/python_api.c
+++ b/src/plugins/python_api.c
@@ -1583,7 +1583,11 @@ static struct PyModuleDef profModule = {
     "prof",
     "",
     -1,
-    apiMethods
+    apiMethods,
+    NULL, /* m_slots */
+    NULL, /* m_traverse */
+    NULL, /* m_clear */
+    NULL  /* m_free */
 };
 #endif
 
diff --git a/src/tools/autocomplete.c b/src/tools/autocomplete.c
index b7fb00b30..7c4cc5347 100644
--- a/src/tools/autocomplete.c
+++ b/src/tools/autocomplete.c
@@ -175,7 +175,7 @@ autocomplete_add(Autocomplete ac, const char* item)
 void
 autocomplete_add_all(Autocomplete ac, char** items)
 {
-    for (int i = 0; i < g_strv_length(items); i++) {
+    for (guint i = 0; i < g_strv_length(items); i++) {
         autocomplete_add(ac, items[i]);
     }
 }
@@ -205,7 +205,7 @@ autocomplete_remove(Autocomplete ac, const char* const item)
 void
 autocomplete_remove_all(Autocomplete ac, char** items)
 {
-    for (int i = 0; i < g_strv_length(items); i++) {
+    for (guint i = 0; i < g_strv_length(items); i++) {
         autocomplete_remove(ac, items[i]);
     }
 }
diff --git a/src/tools/parser.c b/src/tools/parser.c
index addbfbfbf..167e6c1b9 100644
--- a/src/tools/parser.c
+++ b/src/tools/parser.c
@@ -328,7 +328,7 @@ GHashTable*
 parse_options(gchar** args, gchar** opt_keys, gboolean* res)
 {
     GList* keys = NULL;
-    for (int i = 0; i < g_strv_length(opt_keys); i++) {
+    for (guint i = 0; i < g_strv_length(opt_keys); i++) {
         keys = g_list_append(keys, opt_keys[i]);
     }
 
@@ -344,7 +344,7 @@ parse_options(gchar** args, gchar** opt_keys, gboolean* res)
 
     // validate options
     GList* found_keys = NULL;
-    for (int curr = 0; curr < g_strv_length(args); curr += 2) {
+    for (guint curr = 0; curr < g_strv_length(args); curr += 2) {
         // check if option valid
         if (g_list_find_custom(keys, args[curr], (GCompareFunc)g_strcmp0) == NULL) {
             *res = FALSE;
@@ -377,7 +377,7 @@ parse_options(gchar** args, gchar** opt_keys, gboolean* res)
     // create map
     options = g_hash_table_new(g_str_hash, g_str_equal);
     *res = TRUE;
-    for (int curr = 0; curr < g_strv_length(args); curr += 2) {
+    for (guint curr = 0; curr < g_strv_length(args); curr += 2) {
         g_hash_table_insert(options, args[curr], args[curr + 1]);
     }
 
diff --git a/src/ui/console.c b/src/ui/console.c
index c79b1c672..b4c0b7036 100644
--- a/src/ui/console.c
+++ b/src/ui/console.c
@@ -117,7 +117,7 @@ cons_show_help(const char* const cmd, CommandHelp* help)
     cons_show("");
     win_println(console, THEME_HELP_HEADER, "-", "%s", &cmd[1]);
     win_print(console, THEME_HELP_HEADER, "-", "");
-    int i;
+    size_t i;
     for (i = 0; i < strlen(cmd) - 1; i++) {
         win_append(console, THEME_HELP_HEADER, "-");
     }
@@ -131,7 +131,7 @@ cons_show_help(const char* const cmd, CommandHelp* help)
     win_println(console, THEME_HELP_HEADER, "-", "Description");
     win_println(console, THEME_DEFAULT, "-", "%s", help->desc);
 
-    int maxlen = 0;
+    size_t maxlen = 0;
     for (i = 0; help->args[i][0] != NULL; i++) {
         if (strlen(help->args[i][0]) > maxlen)
             maxlen = strlen(help->args[i][0]);
@@ -448,7 +448,7 @@ cons_show_wins(gboolean unread)
 
     GSList* curr = window_strings;
     while (curr) {
-        if (g_strstr_len(curr->data, strlen(curr->data), " unread") > 0) {
+        if (g_strstr_len(curr->data, strlen(curr->data), " unread") != NULL) {
             win_println(console, THEME_CMD_WINS_UNREAD, "-", "%s", curr->data);
         } else {
             win_println(console, THEME_DEFAULT, "-", "%s", curr->data);
@@ -469,7 +469,7 @@ cons_show_wins_attention(void)
 
     GSList* curr = window_strings;
     while (curr) {
-        if (g_strstr_len(curr->data, strlen(curr->data), " unread") > 0) {
+        if (g_strstr_len(curr->data, strlen(curr->data), " unread") != NULL) {
             win_println(console, THEME_CMD_WINS_UNREAD, "-", "%s", curr->data);
         } else {
             win_println(console, THEME_DEFAULT, "-", "%s", curr->data);
@@ -823,7 +823,7 @@ cons_show_qrcode(const char* const text)
     static const size_t ZOOM_SIZE = 10;
     QRcode* qrcode = QRcode_encodeString(text, 0, QR_ECLEVEL_L, QR_MODE_8, 1);
 
-    int width = (qrcode->width * ZOOM_SIZE);
+    size_t width = (qrcode->width * ZOOM_SIZE);
     unsigned char* data = qrcode->data;
 
     ProfWin* console = wins_get_console();
@@ -835,7 +835,7 @@ cons_show_qrcode(const char* const text)
         return;
     }
 
-    for (int i = 0; i < width + 2 * ZOOM_SIZE; i += ZOOM_SIZE) {
+    for (size_t i = 0; i < width + 2 * ZOOM_SIZE; i += ZOOM_SIZE) {
         strcat(pad, "\u2588\u2588");
     }
 
@@ -2760,7 +2760,7 @@ cons_show_bookmarks_ignore(gchar** list, gsize len)
     cons_show("");
     cons_show("Ignored bookmarks:");
 
-    for (int i = 0; i < len; i++) {
+    for (gsize i = 0; i < len; i++) {
         win_print(console, THEME_DEFAULT, "-", "  %s", list[i]);
         win_newline(console);
     }
diff --git a/src/ui/inputwin.c b/src/ui/inputwin.c
index 40200c485..33f275a11 100644
--- a/src/ui/inputwin.c
+++ b/src/ui/inputwin.c
@@ -366,7 +366,7 @@ _inp_write(char* line, int offset)
         if (line[i] == '\n') {
             c = retc;
             ch_len = wctomb(retc, L'\u23ce'); /* return symbol */
-            if (ch_len == -1) {               /* not representable */
+            if (ch_len == (size_t)-1) {       /* not representable */
                 retc[0] = '\\';
                 ch_len = 1;
             }
diff --git a/src/ui/mucwin.c b/src/ui/mucwin.c
index b306aab21..3626699e0 100644
--- a/src/ui/mucwin.c
+++ b/src/ui/mucwin.c
@@ -497,7 +497,7 @@ _mucwin_print_triggers(ProfWin* window, const char* const message, GList* trigge
         }
         trigger_section[i] = '\0';
 
-        if (first_trigger_pos + first_trigger_len < strlen(message)) {
+        if (first_trigger_pos + first_trigger_len < (int)strlen(message)) {
             win_append_highlight(window, THEME_ROOMTRIGGER_TERM, "%s", trigger_section);
             _mucwin_print_triggers(window, &message[first_trigger_pos + first_trigger_len], triggers);
         } else {
diff --git a/src/ui/statusbar.c b/src/ui/statusbar.c
index 2f0e21e4b..8e546df38 100644
--- a/src/ui/statusbar.c
+++ b/src/ui/statusbar.c
@@ -71,24 +71,24 @@ typedef struct _status_bar_t
     char* prompt;
     char* fulljid;
     GHashTable* tabs;
-    int current_tab;
+    guint current_tab;
 } StatusBar;
 
 static GTimeZone* tz;
 static StatusBar* statusbar;
 static WINDOW* statusbar_win;
 
-void _get_range_bounds(int* start, int* end, gboolean is_static);
-static int _status_bar_draw_time(int pos);
-static int _status_bar_draw_maintext(int pos);
-static int _status_bar_draw_bracket(gboolean current, int pos, const char* ch);
-static int _status_bar_draw_extended_tabs(int pos, gboolean prefix, int start, int end, gboolean is_static);
-static int _status_bar_draw_tab(StatusBarTab* tab, int pos, int num, gboolean include_brackets);
-static int _status_bar_draw_tabs(int pos);
+void _get_range_bounds(guint* start, guint* end, gboolean is_static);
+static guint _status_bar_draw_time(guint pos);
+static guint _status_bar_draw_maintext(guint pos);
+static guint _status_bar_draw_bracket(gboolean current, guint pos, const char* ch);
+static guint _status_bar_draw_extended_tabs(guint pos, gboolean prefix, guint start, guint end, gboolean is_static);
+static guint _status_bar_draw_tab(StatusBarTab* tab, guint pos, guint num, gboolean include_brackets);
+static guint _status_bar_draw_tabs(guint pos);
 static void _destroy_tab(StatusBarTab* tab);
-static int _tabs_width(int start, int end);
-static unsigned int _count_digits(int number);
-static unsigned int _count_digits_in_range(int start, int end);
+static guint _tabs_width(guint start, guint end);
+static guint _count_digits(guint number);
+static guint _count_digits_in_range(guint start, guint end);
 static char* _display_name(StatusBarTab* tab);
 static gboolean _tabmode_is_actlist(void);
 
@@ -161,7 +161,7 @@ status_bar_set_all_inactive(void)
 }
 
 void
-status_bar_current(int i)
+status_bar_current(guint i)
 {
     if (i == 0) {
         statusbar->current_tab = 10;
@@ -288,7 +288,7 @@ status_bar_draw(void)
     werase(statusbar_win);
     wbkgd(statusbar_win, theme_attrs(THEME_STATUS_TEXT));
 
-    gint max_tabs = prefs_get_statusbartabs();
+    guint max_tabs = prefs_get_statusbartabs();
     int pos = 1;
 
     pos = _status_bar_draw_time(pos);
@@ -300,24 +300,22 @@ status_bar_draw(void)
     inp_put_back();
 }
 
-static int
-_status_bar_draw_tabs(int pos)
+static guint
+_status_bar_draw_tabs(guint pos)
 {
     auto_gchar gchar* tabmode = prefs_get_string(PREF_STATUSBAR_TABMODE);
 
     if (g_strcmp0(tabmode, "actlist") != 0) {
-        int start, end;
+        guint start, end;
         gboolean is_static = g_strcmp0(tabmode, "dynamic") != 0;
         _get_range_bounds(&start, &end, is_static);
 
-        pos = getmaxx(stdscr) - _tabs_width(start, end);
-        if (pos < 0) {
-            pos = 0;
-        }
+        // if the result of the calc is negative we take 0
+        pos = MAX(0, (getmaxx(stdscr) - (int)_tabs_width(start, end)));
 
         pos = _status_bar_draw_extended_tabs(pos, TRUE, start, end, is_static);
 
-        for (int i = start; i <= end; i++) {
+        for (guint i = start; i <= end; i++) {
             StatusBarTab* tab = g_hash_table_lookup(statusbar->tabs, GINT_TO_POINTER(i));
             if (tab) {
                 pos = _status_bar_draw_tab(tab, pos, i, TRUE);
@@ -365,9 +363,9 @@ _status_bar_draw_tabs(int pos)
 static gboolean
 _has_new_msgs_beyond_range_on_side(gboolean left_side, int display_tabs_start, int display_tabs_end)
 {
-    gint max_tabs = prefs_get_statusbartabs();
+    guint max_tabs = prefs_get_statusbartabs();
     int tabs_count = g_hash_table_size(statusbar->tabs);
-    if (tabs_count <= max_tabs) {
+    if ((guint)tabs_count <= max_tabs) {
         return FALSE;
     }
 
@@ -384,10 +382,10 @@ _has_new_msgs_beyond_range_on_side(gboolean left_side, int display_tabs_start, i
     return FALSE;
 }
 
-static int
-_status_bar_draw_extended_tabs(int pos, gboolean prefix, int start, int end, gboolean is_static)
+static guint
+_status_bar_draw_extended_tabs(guint pos, gboolean prefix, guint start, guint end, gboolean is_static)
 {
-    gint max_tabs = prefs_get_statusbartabs();
+    guint max_tabs = prefs_get_statusbartabs();
     if (max_tabs == 0) {
         return pos;
     }
@@ -426,8 +424,8 @@ _status_bar_draw_extended_tabs(int pos, gboolean prefix, int start, int end, gbo
     return pos;
 }
 
-static int
-_status_bar_draw_tab(StatusBarTab* tab, int pos, int num, gboolean include_brackets)
+static guint
+_status_bar_draw_tab(StatusBarTab* tab, guint pos, guint num, gboolean include_brackets)
 {
     gboolean is_current = num == statusbar->current_tab;
 
@@ -475,8 +473,8 @@ _status_bar_draw_tab(StatusBarTab* tab, int pos, int num, gboolean include_brack
     return pos;
 }
 
-static int
-_status_bar_draw_bracket(gboolean current, int pos, const char* ch)
+static guint
+_status_bar_draw_bracket(gboolean current, guint pos, const char* ch)
 {
     int bracket_attrs = theme_attrs(THEME_STATUS_BRACKET);
     wattron(statusbar_win, bracket_attrs);
@@ -491,8 +489,8 @@ _status_bar_draw_bracket(gboolean current, int pos, const char* ch)
     return pos;
 }
 
-static int
-_status_bar_draw_time(int pos)
+static guint
+_status_bar_draw_time(guint pos)
 {
     auto_gchar gchar* time_pref = prefs_get_string(PREF_TIME_STATUSBAR);
     if (g_strcmp0(time_pref, "off") == 0) {
@@ -536,8 +534,8 @@ _tabmode_is_actlist(void)
     return g_strcmp0(tabmode, "actlist") == 0;
 }
 
-static int
-_status_bar_draw_maintext(int pos)
+static guint
+_status_bar_draw_maintext(guint pos)
 {
     const char* maintext = NULL;
     auto_jid Jid* jidp = NULL;
@@ -597,20 +595,20 @@ _destroy_tab(StatusBarTab* tab)
     }
 }
 
-static int
-_tabs_width(int start, int end)
+static guint
+_tabs_width(guint start, guint end)
 {
     gboolean show_number = prefs_get_boolean(PREF_STATUSBAR_SHOW_NUMBER);
     gboolean show_name = prefs_get_boolean(PREF_STATUSBAR_SHOW_NAME);
     gboolean show_read = prefs_get_boolean(PREF_STATUSBAR_SHOW_READ);
-    gint max_tabs = prefs_get_statusbartabs();
+    guint max_tabs = prefs_get_statusbartabs();
     guint opened_tabs = g_hash_table_size(statusbar->tabs);
 
     int width = start < 2 ? 1 : 4;
     width += end > opened_tabs - 1 ? 0 : 3;
 
     if (show_name && show_number) {
-        for (int i = start; i <= end; i++) {
+        for (guint i = start; i <= end; i++) {
             StatusBarTab* tab = g_hash_table_lookup(statusbar->tabs, GINT_TO_POINTER(i));
             if (tab) {
                 gboolean is_current = i == statusbar->current_tab;
@@ -627,7 +625,7 @@ _tabs_width(int start, int end)
     }
 
     if (show_name && !show_number) {
-        for (int i = start; i <= end; i++) {
+        for (guint i = start; i <= end; i++) {
             StatusBarTab* tab = g_hash_table_lookup(statusbar->tabs, GINT_TO_POINTER(i));
             if (tab) {
                 gboolean is_current = i == statusbar->current_tab;
@@ -698,7 +696,7 @@ _display_name(StatusBarTab* tab)
 }
 
 void
-_get_range_bounds(int* start, int* end, gboolean is_static)
+_get_range_bounds(guint* start, guint* end, gboolean is_static)
 {
     int current_tab = statusbar->current_tab;
     gint display_range = prefs_get_statusbartabs();
@@ -721,12 +719,10 @@ _get_range_bounds(int* start, int* end, gboolean is_static)
 }
 
 // Counts amount of digits in a number
-static unsigned int
-_count_digits(int number)
+static guint
+_count_digits(guint number)
 {
-    unsigned int digits_count = 0;
-    if (number < 0)
-        number = -number;
+    guint digits_count = 0;
 
     do {
         number /= 10;
@@ -738,12 +734,11 @@ _count_digits(int number)
 
 // Counts the total number of digits in a range of numbers, inclusive.
 // Example: _count_digits_in_range(2, 3) returns 2, _count_digits_in_range(2, 922) returns 2657
-static unsigned int
-_count_digits_in_range(int start, int end)
+static guint
+_count_digits_in_range(guint start, guint end)
 {
-    int total_digits = 0;
-
-    for (int i = start; i <= end; i++) {
+    guint total_digits = 0;
+    for (guint i = start; i <= end; i++) {
         total_digits += _count_digits(i);
     }
 
diff --git a/src/ui/statusbar.h b/src/ui/statusbar.h
index 4946e8c37..82a934857 100644
--- a/src/ui/statusbar.h
+++ b/src/ui/statusbar.h
@@ -44,6 +44,6 @@ void status_bar_set_prompt(const char* const prompt);
 void status_bar_clear_prompt(void);
 void status_bar_set_fulljid(const char* const fulljid);
 void status_bar_clear_fulljid(void);
-void status_bar_current(int i);
+void status_bar_current(guint i);
 
 #endif
diff --git a/src/ui/window.c b/src/ui/window.c
index 88271b344..d11120eba 100644
--- a/src/ui/window.c
+++ b/src/ui/window.c
@@ -1871,7 +1871,7 @@ _win_print_wrapped(WINDOW* win, const char* const message, size_t indent, int pa
                     curr_ch++;
                     continue;
                 }
-                int offset = 0;
+                size_t offset = 0;
                 while (offset < ch_len) {
                     word[wordi++] = curr_ch[offset++];
                 }
@@ -1880,9 +1880,9 @@ _win_print_wrapped(WINDOW* win, const char* const message, size_t indent, int pa
             word[wordi] = '\0';
             wordlen = utf8_display_len(word);
 
-            int curx = getcurx(win);
+            size_t curx = (size_t)getcurx(win);
             int cury;
-            int maxx = getmaxx(win);
+            size_t maxx = getmaxx(win);
 
             // wrap required
             if (curx + wordlen > maxx) {
@@ -1892,7 +1892,7 @@ _win_print_wrapped(WINDOW* win, const char* const message, size_t indent, int pa
                 if (wordlen > linelen) {
                     gchar* word_ch = g_utf8_offset_to_pointer(word, 0);
                     while (*word_ch != '\0') {
-                        curx = getcurx(win);
+                        curx = (size_t)getcurx(win);
                         cury = getcury(win);
                         gboolean firstline = cury == starty;
 
@@ -1913,7 +1913,7 @@ _win_print_wrapped(WINDOW* win, const char* const message, size_t indent, int pa
                     // newline and print word
                 } else {
                     waddch(win, '\n');
-                    curx = getcurx(win);
+                    curx = (size_t)getcurx(win);
                     cury = getcury(win);
                     gboolean firstline = cury == starty;
 
@@ -1928,7 +1928,7 @@ _win_print_wrapped(WINDOW* win, const char* const message, size_t indent, int pa
 
                 // no wrap required
             } else {
-                curx = getcurx(win);
+                curx = (size_t)getcurx(win);
                 cury = getcury(win);
                 gboolean firstline = cury == starty;
 
diff --git a/src/xmpp/capabilities.c b/src/xmpp/capabilities.c
index 8f1cf6d6b..112b83451 100644
--- a/src/xmpp/capabilities.c
+++ b/src/xmpp/capabilities.c
@@ -376,7 +376,7 @@ _caps_by_ver(const char* const ver)
     auto_gcharv gchar** features_list = g_key_file_get_string_list(cache, ver, "features", &features_len, NULL);
     GSList* features = NULL;
     if (features_list && features_len > 0) {
-        for (int i = 0; i < features_len; i++) {
+        for (gsize i = 0; i < features_len; i++) {
             features = g_slist_append(features, features_list[i]);
         }
     }
diff --git a/src/xmpp/iq.c b/src/xmpp/iq.c
index a8a485b2d..4c3330626 100644
--- a/src/xmpp/iq.c
+++ b/src/xmpp/iq.c
@@ -248,6 +248,12 @@ _iq_handler(xmpp_conn_t* const conn, xmpp_stanza_t* const stanza, void* const us
     return 1;
 }
 
+static void
+_xmpp_stanza_release_destroy_notify(gpointer data)
+{
+    xmpp_stanza_release((xmpp_stanza_t*)data);
+}
+
 void
 iq_handlers_init(void)
 {
@@ -264,7 +270,7 @@ iq_handlers_init(void)
     iq_handlers_clear();
 
     id_handlers = g_hash_table_new_full(g_str_hash, g_str_equal, free, (GDestroyNotify)_iq_id_handler_free);
-    rooms_cache = g_hash_table_new_full(g_str_hash, g_str_equal, free, (GDestroyNotify)xmpp_stanza_release);
+    rooms_cache = g_hash_table_new_full(g_str_hash, g_str_equal, free, _xmpp_stanza_release_destroy_notify);
 }
 
 struct iq_win_finder
@@ -302,7 +308,7 @@ _free_late_delivery_userdata(LateDeliveryUserdata* d)
 void
 iq_handlers_remove_win(ProfWin* window)
 {
-    log_debug("Remove window %p of type %d", window, window ? window->type : -1);
+    log_debug("Remove window %p of type %d", window, window ? window->type : (win_type_t)-1);
     if (!window)
         return;
     GSList *cur = late_delivery_windows, *next;
@@ -394,7 +400,7 @@ iq_autoping_check(void)
     }
 
     gdouble elapsed = g_timer_elapsed(autoping_time, NULL);
-    unsigned long seconds_elapsed = elapsed * 1.0;
+    gint seconds_elapsed = elapsed * 1.0;
     gint timeout = prefs_get_autoping_timeout();
     if (timeout > 0 && seconds_elapsed >= timeout) {
         cons_show("Autoping response timed out after %u seconds.", timeout);
diff --git a/src/xmpp/muc.c b/src/xmpp/muc.c
index 312ac941e..0418667be 100644
--- a/src/xmpp/muc.c
+++ b/src/xmpp/muc.c
@@ -427,7 +427,7 @@ muc_rooms(void)
  * Return current users nickname for the specified room
  * The nickname is owned by the chat room and should not be modified or freed
  */
-const char* const
+const char*
 muc_nick(const char* const room)
 {
     ChatRoom* chat_room = g_hash_table_lookup(rooms, room);
diff --git a/src/xmpp/muc.h b/src/xmpp/muc.h
index 7ae7a0c9d..cb1c6afeb 100644
--- a/src/xmpp/muc.h
+++ b/src/xmpp/muc.h
@@ -93,7 +93,7 @@ GList* muc_rooms(void);
 
 void muc_set_features(const char* const room, GSList* features);
 
-const char* const muc_nick(const char* const room);
+const char* muc_nick(const char* const room);
 char* muc_password(const char* const room);
 
 void muc_nick_change_start(const char* const room, const char* const new_nick);
diff --git a/src/xmpp/session.c b/src/xmpp/session.c
index 86990ce85..ebd49fef7 100644
--- a/src/xmpp/session.c
+++ b/src/xmpp/session.c
@@ -424,8 +424,8 @@ session_check_autoaway(void)
     gboolean check = prefs_get_boolean(PREF_AUTOAWAY_CHECK);
     gint away_time = prefs_get_autoaway_time();
     gint xa_time = prefs_get_autoxa_time();
-    int away_time_ms = away_time * 60000;
-    int xa_time_ms = xa_time * 60000;
+    unsigned long away_time_ms = away_time * 60000;
+    unsigned long xa_time_ms = xa_time * 60000;
 
     const char* account = session_get_account_name();
     resource_presence_t curr_presence = accounts_get_last_presence(account);
diff --git a/src/xmpp/stanza.c b/src/xmpp/stanza.c
index 3eef2a9f4..2bca1913b 100644
--- a/src/xmpp/stanza.c
+++ b/src/xmpp/stanza.c
@@ -222,7 +222,7 @@ stanza_create_http_upload_request(xmpp_ctx_t* ctx, const char* const id,
 
     auto_char char* filename_cpy = strdup(upload->filename);
     // strip spaces from filename (servers don't spaces)
-    for (int i = 0; i < strlen(filename_cpy); i++) {
+    for (size_t i = 0; i < strlen(filename_cpy); i++) {
         if (filename_cpy[i] == ' ') {
             filename_cpy[i] = '_';
         }
@@ -1863,7 +1863,7 @@ stanza_get_error_message(xmpp_stanza_t* stanza)
             STANZA_NAME_UNEXPECTED_REQUEST
         };
 
-        for (int i = 0; i < ARRAY_SIZE(defined_conditions); i++) {
+        for (size_t i = 0; i < ARRAY_SIZE(defined_conditions); i++) {
             xmpp_stanza_t* cond_stanza = xmpp_stanza_get_child_by_name(error_stanza, defined_conditions[i]);
             if (cond_stanza) {
                 char* result = strdup(xmpp_stanza_get_name(cond_stanza));