diff --git a/modoboa/demo/views.py b/modoboa/demo/views.py
index 19b9e14ea..18e2a8427 100755
--- a/modoboa/demo/views.py
+++ b/modoboa/demo/views.py
@@ -3,10 +3,11 @@ import os
 from django.conf import settings
 from django.contrib.auth.decorators import login_required
 from django.utils.translation import ugettext as _
-from modoboa.lib.webutils import ajax_simple_response
+from modoboa.lib.webutils import render_to_json_response
 from modoboa.lib.emailutils import sendmail_simple, sendmail_fromfile
 from modoboa.lib.decorators import needs_mailbox
 
+
 @login_required
 @needs_mailbox()
 def send_virus(request):
@@ -14,8 +15,9 @@ def send_virus(request):
                                       os.path.join(settings.MODOBOA_DIR,
                                                    "tmp/virus.msg"))
     if status:
-        return ajax_simple_response(dict(status="ok", respmsg=_("Message sent")))
-    return ajax_simple_response(dict(status="ko", respmsg=error))
+        return render_to_json_response(_("Message sent"))
+    return render_to_json_response(error, status=500)
+
 
 @login_required
 @needs_mailbox()
@@ -38,5 +40,5 @@ XJS*C4JDBQADN1.NSBN3*2IDNEN*GTUBE-STANDARD-ANTI-UBE-TEST-EMAIL*C.34X
 You should send this test mail from an account outside of your network.
 """)
     if status:
-        return ajax_simple_response(dict(status="ok", respmsg=_("Message sent")))
-    return ajax_simple_response(dict(status="ko", respmsg=error))
+        return render_to_json_response(_("Message sent"))
+    return render_to_json_response(respmsg=error, status=500)
diff --git a/modoboa/extensions/admin/views/domain.py b/modoboa/extensions/admin/views/domain.py
index 29b43132c..38cd61f10 100644
--- a/modoboa/extensions/admin/views/domain.py
+++ b/modoboa/extensions/admin/views/domain.py
@@ -9,8 +9,7 @@ from django.contrib.auth.decorators import (
 )
 from modoboa.lib import parameters, events
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string,
-    render_to_json_response
+    _render_to_string, render_to_json_response
 )
 from modoboa.lib.formutils import CreationWizard
 from modoboa.lib.exceptions import (
@@ -53,7 +52,7 @@ def _domains(request):
         domainlist = sorted(domainlist, key=lambda d: d.tags[0],
                             reverse=sort_dir == '-')
     page = get_listing_page(domainlist, request.GET.get("page", 1))
-    return ajax_simple_response({
+    return render_to_json_response({
         "table": _render_to_string(request, 'admin/domains_table.html', {
             'domains': page.object_list,
             'tableid': 'domains'
@@ -82,7 +81,7 @@ def domains(request, tplname="admin/domains.html"):
 @permission_required("core.add_user")
 def domains_list(request):
     doms = [dom.name for dom in Domain.objects.get_for_admin(request.user)]
-    return ajax_simple_response(doms)
+    return render_to_json_response(doms)
 
 
 @login_required
diff --git a/modoboa/extensions/admin/views/identity.py b/modoboa/extensions/admin/views/identity.py
index 7ab550a68..e44ac9d87 100644
--- a/modoboa/extensions/admin/views/identity.py
+++ b/modoboa/extensions/admin/views/identity.py
@@ -11,8 +11,7 @@ from modoboa.lib.exceptions import (
     ModoboaException, PermDeniedException, BadRequest
 )
 from modoboa.lib.webutils import (
-    ajax_simple_response, _render_to_string,
-    render_to_json_response
+    _render_to_string, render_to_json_response
 )
 from modoboa.lib.formutils import CreationWizard
 from modoboa.lib.templatetags.lib_tags import pagination_bar
@@ -44,7 +43,7 @@ def _identities(request):
         objects = sorted(idents_list, key=lambda o: o.tags[0],
                          reverse=sort_dir == '-')
     page = get_listing_page(objects, request.GET.get("page", 1))
-    return ajax_simple_response({
+    return render_to_json_response({
         "table": _render_to_string(request, "admin/identities_table.html", {
             "identities": page.object_list,
             "tableid": "objects_table"
@@ -74,7 +73,7 @@ def accounts_list(request):
     accs = User.objects.filter(is_superuser=False) \
         .exclude(groups__name='SimpleUsers')
     res = [a.username for a in accs.all()]
-    return ajax_simple_response(res)
+    return render_to_json_response(res)
 
 
 @login_required
@@ -103,8 +102,7 @@ def list_quotas(request, tplname="admin/quotas.html"):
     else:
         raise BadRequest(_("Invalid request"))
     page = get_listing_page(mboxes, request.GET.get("page", 1))
-    return ajax_simple_response({
-        "status": "ok",
+    return render_to_json_response({
         "page": page.number,
         "paginbar": pagination_bar(page),
         "table": _render_to_string(request, tplname, {
@@ -231,4 +229,4 @@ def remove_permission(request):
     if not request.user.can_access(account) or not request.user.can_access(domain):
         raise PermDeniedException
     domain.remove_admin(account)
-    return ajax_simple_response({"status": "ok"})
+    return render_to_json_response({})
diff --git a/modoboa/extensions/amavis/static/amavis/js/quarantine.js b/modoboa/extensions/amavis/static/amavis/js/quarantine.js
index 699c37252..bb4b8ff57 100644
--- a/modoboa/extensions/amavis/static/amavis/js/quarantine.js
+++ b/modoboa/extensions/amavis/static/amavis/js/quarantine.js
@@ -117,9 +117,8 @@ Quarantine.prototype = {
             url: $link.attr("href"),
             data: "action=" + name + "&selection=" + selection.join(","),
             type: 'POST',
-            dataType: 'json',
-            success: $.proxy(this.action_cb, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(this.action_cb, this));
     },
 
     release_selection: function(e) {
@@ -139,9 +138,8 @@ Quarantine.prototype = {
         }
         $.ajax({
             url: $link.attr("href"),
-            dataType: 'json',
-            success: $.proxy(this.action_cb, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(this.action_cb, this));
     },
 
     release: function(e) {
@@ -175,11 +173,11 @@ Quarantine.prototype = {
         if (!$rawheaders.length) {
             $.ajax({
                 url: $link.attr("href"),
-                success: $.proxy(function(data) {
-                    $mailcontent.find("#table-container").append($(data));
-                    this.show_rawheaders($mailcontent);
-                }, this)
-            });
+                global: false
+            }).done($.proxy(function(data) {
+                $mailcontent.find("#table-container").append($(data));
+                this.show_rawheaders($mailcontent);
+            }, this));
             return;
         }
         this.show_rawheaders($mailcontent);
diff --git a/modoboa/extensions/amavis/static/amavis/js/selfservice.js b/modoboa/extensions/amavis/static/amavis/js/selfservice.js
index 8aecf6d04..d634f9bfa 100644
--- a/modoboa/extensions/amavis/static/amavis/js/selfservice.js
+++ b/modoboa/extensions/amavis/static/amavis/js/selfservice.js
@@ -7,14 +7,9 @@ function send_action(e, message) {
     }
     $.ajax({
         url: $link.attr("href"),
-        dataType: 'json',
-        success: function(data) {
-            if (data.status == "ok") {
-                $("body").notify("success", data.respmsg, 2000);
-            } else {
-                $("body").notify("error", data.respmsg);
-            }
-        }
+        dataType: 'json'
+    }).done(function(data) {
+        $("body").notify("success", data, 2000);
     });
 }
 
diff --git a/modoboa/extensions/amavis/views.py b/modoboa/extensions/amavis/views.py
index 261110f2c..f1973b966 100644
--- a/modoboa/extensions/amavis/views.py
+++ b/modoboa/extensions/amavis/views.py
@@ -10,13 +10,15 @@ from django.contrib.auth.decorators \
     import login_required, user_passes_test
 from django.db.models import Q
 from modoboa.lib import parameters
-from modoboa.lib.exceptions import ModoboaException
+from modoboa.lib.exceptions import ModoboaException, BadRequest
 from modoboa.lib.webutils import (
-    getctx, ajax_response, ajax_simple_response
+    getctx, ajax_response, render_to_json_response
 )
 from modoboa.lib.email_listing import parse_search_parameters
 from modoboa.extensions.admin.models import Mailbox, Domain
-from templatetags.amavis_tags import quar_menu, viewm_menu
+from modoboa.extensions.amavis.templatetags.amavis_tags import (
+    quar_menu, viewm_menu
+)
 from .lib import selfservice, AMrelease
 from .sql_listing import SQLlisting, SQLemail, get_wrapper
 from .models import Msgrcpt
@@ -79,7 +81,7 @@ def _listing(request):
                 rcptfilter = request.session["pattern"]
                 continue
             else:
-                raise Exception("unsupported search criteria %s" % c)
+                raise BadRequest("unsupported search criteria %s" % c)
             flt = nfilter if flt is None else flt | nfilter
 
     msgs = get_wrapper().get_mails(request, rcptfilter)
@@ -202,14 +204,14 @@ def check_mail_id(request, mail_id):
 def delete_selfservice(request, mail_id):
     rcpt = request.GET.get("rcpt", None)
     if rcpt is None:
-        raise ModoboaException(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     try:
         msgrcpt = get_wrapper().get_recipient_message(rcpt, mail_id)
         msgrcpt.rs = 'D'
         msgrcpt.save()
     except Msgrcpt.DoesNotExist:
-        raise ModoboaException(_("Invalid request"))
-    return ajax_simple_response(dict(status="ok", respmsg=_("Message deleted")))
+        raise BadRequest(_("Invalid request"))
+    return render_to_json_response(_("Message deleted"))
 
 
 @selfservice(delete_selfservice)
@@ -241,13 +243,13 @@ def release_selfservice(request, mail_id):
     rcpt = request.GET.get("rcpt", None)
     secret_id = request.GET.get("secret_id", None)
     if rcpt is None or secret_id is None:
-        raise ModoboaException(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     try:
         msgrcpt = get_wrapper().get_recipient_message(rcpt, mail_id)
     except Msgrcpt.DoesNotExist:
-        raise ModoboaException(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     if secret_id != msgrcpt.mail.secret_id:
-        raise ModoboaException(_("Invalid request"))
+        raise BadRequest(_("Invalid request"))
     if parameters.get_admin("USER_CAN_RELEASE") == "no":
         msgrcpt.rs = 'p'
         msg = _("Request sent")
@@ -258,9 +260,9 @@ def release_selfservice(request, mail_id):
             rcpt.rs = 'R'
             msg = _("Message released")
         else:
-            raise ModoboaException(result)
+            raise BadRequest(result)
     msgrcpt.save()
-    return ajax_simple_response(dict(status="ok", respmsg=msg))
+    return render_to_json_response(msg)
 
 
 @selfservice(release_selfservice)
@@ -329,4 +331,4 @@ def process(request):
 @user_passes_test(lambda u: u.group != 'SimpleUsers')
 def nbrequests(request):
     result = get_wrapper().get_pending_requests(request.user)
-    return ajax_simple_response(dict(status="ok", requests=result))
+    return render_to_json_response({'requests': result})
diff --git a/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js b/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js
index f14188ee0..fc454ab39 100644
--- a/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js
+++ b/modoboa/extensions/postfix_relay_domains/static/postfix_relay_domains/js/relay_domains.js
@@ -33,7 +33,8 @@ RelayDomains.prototype = {
         e.preventDefault();
         $.ajax({
             type: "POST",
-            url: $link.attr("href")
+            url: $link.attr("href"),
+            global: false
         }).done(function(data) {
             var $widget = $('#id_service');
 
@@ -48,9 +49,6 @@ RelayDomains.prototype = {
                 build_success_alert(gettext('Services updated'))
             );
         }).fail(function(jqxhr) {
-            if (jqxhr.getResponseHeader('Content-Type') != 'application/json') {
-                return;
-            }
             var result = $.parseJSON(jqxhr.responseText);
             $('.modal-body').prepend(
                 build_error_alert(result[0])
diff --git a/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js b/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js
index 3c8336806..700a4e423 100644
--- a/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js
+++ b/modoboa/extensions/sievefilters/static/sievefilters/js/lib.js
@@ -22,9 +22,6 @@ function removefilter(evt) {
     }).done(function(response) {
         history.update(true);
         $("body").notify('success', response, 2000);
-    }).fail(function(jqxhr) {
-        var response = $.parseJSON(jqxhr.responseText);
-        $("body").notify('error', response);
     });
 }
 
@@ -75,20 +72,15 @@ function loadfs(response) {
 function send_command(cmd, extracb) {
     $.ajax({
         url: cmd,
-        dataType: 'json',
-        success: function(response) {
-            if (response.status == "ko") {
-                $("body").notify('error', response.respmsg);
-            } else {
-                if (extracb != undefined) {
-                    extracb(response);
-                }
-                if (!response.norefresh) {
-                    history.update(true);
-                }
-                $("body").notify('success', response.respmsg, 2000);
-            }
+        dataType: 'json'
+    }).done(function(response) {
+        if (extracb != undefined) {
+            extracb(response);
         }
+        if (!response.norefresh) {
+            history.update(true);
+        }
+        $("body").notify('success', response.respmsg, 2000);
     });
 }
 
@@ -121,14 +113,9 @@ function savefs(evt) {
         url: $editor.attr("action"),
         type: $editor.attr("method"),
         dataType: 'json',
-        data: $editor.serialize(),
-        success: function(response) {
-            if (response.status == "ko") {
-                $("body").notify('error', response.respmsg);
-            } else {
-                $("body").notify('success', response.respmsg, 2000);
-            }
-        }
+        data: $editor.serialize()
+    }).done(function(response) {
+        $("body").notify('success', response.respmsg, 2000);
     });
 }
 
@@ -184,9 +171,6 @@ function toggle_filter_state(event) {
         $this.html(response.label);
         $this.attr("class", "");
         $this.addClass(response.color);
-    }).fail(function(jqhxr) {
-        var response = $.parseJSON(jqxhr.responseText);
-        $("body").notify('error', response);
     });
 }
 
@@ -200,9 +184,6 @@ function move_filter(event) {
     }).done(function(response) {
         $("#set_content").html(response.content);
         init_filters_list();
-    }).fail(function(jqxhr) {
-        var response = $.parseJSON(jqxhr.responseText);
-        $("body").notify('error', response);
     });
 }
 
@@ -254,8 +235,9 @@ function fetch_templates(url, container) {
     $.ajax({
         url: url,
         async: false,
-        dataType: 'json',
-        success: function(data) { result = data; }
+        dataType: 'json'
+    }).done(function(data) {
+        result = data;
     });
     return result;
 }
\ No newline at end of file
diff --git a/modoboa/extensions/stats/static/stats/js/stats.js b/modoboa/extensions/stats/static/stats/js/stats.js
index 557ef7786..fcf21a5ff 100644
--- a/modoboa/extensions/stats/static/stats/js/stats.js
+++ b/modoboa/extensions/stats/static/stats/js/stats.js
@@ -79,10 +79,6 @@ Stats.prototype = {
     },
 
     graphs_cb: function(data) {
-        if (data.status == "ko") {
-            $("body").notify("error", data.respmsg);
-            return;
-        }
         if (data.content) {
             $(".tab-pane.active").html(data.content);
         }
diff --git a/modoboa/extensions/stats/views.py b/modoboa/extensions/stats/views.py
index b9fee9083..accd7608f 100644
--- a/modoboa/extensions/stats/views.py
+++ b/modoboa/extensions/stats/views.py
@@ -7,7 +7,7 @@ from django.contrib.auth.decorators import (
 from modoboa.lib import events
 from modoboa.lib.exceptions import ModoboaException, PermDeniedException
 from modoboa.lib.webutils import (
-    _render_to_string, ajax_simple_response
+    _render_to_string, render_to_json_response
 )
 from modoboa.extensions.admin.models import (
     Domain
@@ -50,7 +50,7 @@ def graphs(request):
     if searchq in [None, "global"]:
         if not request.user.is_superuser:
             if not Domain.objects.get_for_admin(request.user).count():
-                return ajax_simple_response({"status": "ok"})
+                return render_to_json_response({})
             tplvars.update(
                 domain=Domain.objects.get_for_admin(request.user)[0].name
             )
@@ -59,7 +59,7 @@ def graphs(request):
     else:
         domain = Domain.objects.filter(name__contains=searchq)
         if domain.count() != 1:
-            return ajax_simple_response({"status": "ok"})
+            return render_to_json_response({})
         if not request.user.can_access(domain[0]):
             raise PermDeniedException
         tplvars.update(domain=domain[0].name)
@@ -83,7 +83,6 @@ def graphs(request):
     else:
         tplvars['graphs'] = gsets[gset].get_graph_names()
 
-    return ajax_simple_response(dict(
-        status="ok",
-        content=_render_to_string(request, "stats/graphs.html", tplvars)
-    ))
+    return render_to_json_response({
+        'content': _render_to_string(request, "stats/graphs.html", tplvars)
+    })
diff --git a/modoboa/extensions/webmail/static/webmail/js/webmail.js b/modoboa/extensions/webmail/static/webmail/js/webmail.js
index 829c477ac..d3440efd7 100644
--- a/modoboa/extensions/webmail/static/webmail/js/webmail.js
+++ b/modoboa/extensions/webmail/static/webmail/js/webmail.js
@@ -261,8 +261,8 @@ Webmail.prototype = {
      * Poller callback.
      */
     poller_cb: function(data) {
-        for (var mb in data.counters) {
-            this.set_unseen_messages(mb, parseInt(data.counters[mb]));
+        for (var mb in data) {
+            this.set_unseen_messages(mb, parseInt(data[mb]));
         }
     },
 
@@ -341,14 +341,10 @@ Webmail.prototype = {
             url: this.options.submboxes_url,
             dataType: 'json',
             async: async,
-            data: "topmailbox=" + parent.attr("name"),
-            success: $.proxy(function(data) {
-                if (data.status == "ko") {
-                    return;
-                }
-                this.inject_mailboxes(parent, data.mboxes);
-            }, this)
-        });
+            data: "topmailbox=" + parent.attr("name")
+        }).done($.proxy(function(data) {
+            this.inject_mailboxes(parent, data);
+        }, this));
     },
 
     /*
@@ -482,17 +478,12 @@ Webmail.prototype = {
 
         $.ajax({
             url: $link.attr("href") + "?name=" + $selected.attr("href"),
-            dataType: 'json',
-            success: $.proxy(function(data) {
-                if (data.status == "ok") {
-                    this.remove_mbox_from_tree(this.navobject.getparam("mbox"));
-                    this.poller.resume();
-                    $("body").notify("success", gettext("Mailbox removed"), 2000);
-                } else {
-                    $("body").notify("error", data.respmsg);
-                }
-            }, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(function(data) {
+            this.remove_mbox_from_tree(this.navobject.getparam("mbox"));
+            this.poller.resume();
+            $("body").notify("success", gettext("Mailbox removed"), 2000);
+        }, this));
     },
 
     /*
@@ -587,25 +578,19 @@ Webmail.prototype = {
         $.ajax({
             url: $link.attr("href"),
             data: "ids=" + selection.join(","),
-            dataType: 'json',
-            success: $.proxy(this.mark_callback, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(this.mark_callback, this));
     },
 
     send_mb_action: function(url, cb) {
         $.ajax({
             url: url,
-            dataType: 'json',
-            success: $.proxy(function(data) {
-                if (data.status == "ko") {
-                    $("body").notify("error", data.respmsg);
-                    return;
-                }
-                if (cb != undefined) {
-                    cb.apply(this, [data]);
-                }
-            }, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(function(data) {
+            if (cb != undefined) {
+                cb.apply(this, [data]);
+            }
+        }, this));
     },
 
     empty: function(e) {
@@ -629,8 +614,8 @@ Webmail.prototype = {
         e.preventDefault();
         $.ajax({
             url: $link.attr("href"),
-            success: $.proxy(this.delete_callback, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(this.delete_callback, this));
     },
 
     delete_messages: function(e) {
@@ -658,9 +643,8 @@ Webmail.prototype = {
         this.change_unseen_messages(this.options.trash, unseen_cnt);
         $.ajax({
             url: $link.attr("href"),
-            data: {mbox: this.get_current_mailbox(), selection: selection},
-            success: $.proxy(this.delete_callback, this)
-        });
+            data: {mbox: this.get_current_mailbox(), selection: selection}
+        }).done($.proxy(this.delete_callback, this));
     },
 
     display_mode: function(e, value) {
@@ -737,8 +721,18 @@ Webmail.prototype = {
             data: args,
             dataType: 'json',
             type: 'POST',
-            success: $.proxy(this.sendmail_callback, this)
-        });
+            global: false
+        }).done($.proxy(function(data) {
+            this._listmailbox_loader(null, $("#folders").find("li[class*=active]").children("a"));
+            $("body").notify("success", gettext("Message sent"), 2000);
+        }, this)).fail($.proxy(function(jqxhr) {
+            var data = $.parseJSON(jqxhr.responseText);
+            this.navobject.get_callback("compose")(data);
+            if (data.respmsg != undefined) {
+                $("body").notify("error", data.respmsg);
+            }
+            $("a[name=sendmail]").attr("disabled", null);
+        }, this));
     },
 
     /*
@@ -833,19 +827,6 @@ Webmail.prototype = {
         });
     },
 
-    sendmail_callback: function(data) {
-        if (data.status == "ko") {
-            this.navobject.get_callback("compose")(data);
-            if (data.respmsg != undefined) {
-                $("body").notify("error", data.respmsg);
-            }
-            $("a[name=sendmail]").attr("disabled", null);
-            return;
-        }
-        this._listmailbox_loader(null, $("#folders").find("li[class*=active]").children("a"));
-        $("body").notify("success", gettext("Message sent"), 2000);
-    },
-
     /*
      * Callback of the 'viewmail' action
      */
@@ -859,10 +840,6 @@ Webmail.prototype = {
     },
 
     mark_callback: function(data) {
-        if (data.status == "ko") {
-            $("body").notify("error", data.respmsg);
-            return;
-        }
         if (data.action == "read") {
             this.htmltable.current_selection().removeClass("unseen");
         } else {
@@ -874,16 +851,13 @@ Webmail.prototype = {
     },
 
     delete_callback: function(data) {
-        if (data.status == "ok") {
-            var msg = (data.respmsg) ? data.respmsg : gettext("Message deleted");
-            this.go_back_to_listing();
-            if (this.get_current_mailbox() != this.options.trash) {
-                $("a[name=totrash]").removeClass("disabled");
-            }
-            $("body").notify("success", msg, 2000);
-        } else {
-            $("body").notify("error", data.respmsg);
+        var msg = (data.respmsg) ? data.respmsg : gettext("Message deleted");
+
+        this.go_back_to_listing();
+        if (this.get_current_mailbox() != this.options.trash) {
+            $("a[name=totrash]").removeClass("disabled");
         }
+        $("body").notify("success", msg, 2000);
     },
 
     /*
@@ -972,10 +946,9 @@ Webmail.prototype = {
         var $this = $(this);
 
         $.ajax({
-            url: $this.attr("href"),
-            success: function() {
-                $this.parent().remove();
-            }
+            url: $this.attr("href")
+        }).done(function() {
+            $this.parent().remove();
         });
     },
 
@@ -1069,18 +1042,13 @@ Webmail.prototype = {
                 $.ajax({
                     url: plug.options.move_url,
                     data: "msgset=" + selection.join() + "&to=" + to,
-                    dataType: 'json',
-                    success: function(data) {
-                        if (data.status == "ok") {
-                            if (unseen_cnt) {
-                                plug.change_unseen_messages(from, -unseen_cnt);
-                                plug.change_unseen_messages(to, unseen_cnt);
-                            }
-                            plug.listmailbox_callback(data);
-                        } else {
-                            $("body").notify("error", data.respmsg);
-                        }
+                    dataType: 'json'
+                }).done(function(data) {
+                    if (unseen_cnt) {
+                        plug.change_unseen_messages(from, -unseen_cnt);
+                        plug.change_unseen_messages(to, unseen_cnt);
                     }
+                    plug.listmailbox_callback(data);
                 });
             }
         });
diff --git a/modoboa/extensions/webmail/views.py b/modoboa/extensions/webmail/views.py
index 5291f8a7a..58e4c949b 100644
--- a/modoboa/extensions/webmail/views.py
+++ b/modoboa/extensions/webmail/views.py
@@ -12,8 +12,7 @@ from django.views.decorators.csrf import csrf_exempt
 from django.views.decorators.gzip import gzip_page
 from modoboa.lib import parameters
 from modoboa.lib.webutils import (
-    _render_to_string, ajax_response, ajax_simple_response,
-    render_to_json_response
+    _render_to_string, ajax_response, render_to_json_response
 )
 from modoboa.extensions.admin.lib import needs_mailbox
 from .exceptions import WebmailError
@@ -23,7 +22,7 @@ from .lib import (
     decode_payload, AttachmentUploadHandler,
     save_attachment, ImapListing, EmailSignature,
     clean_attachments, set_compose_session, send_mail,
-    ImapEmail
+    ImapEmail, ReplyModifier, ForwardModifier
 )
 from templatetags import webmail_tags
 
@@ -66,8 +65,7 @@ def move(request):
     mbc = get_imapconnector(request)
     mbc.move(request.GET["msgset"], request.session["mbox"], request.GET["to"])
     resp = listmailbox(request, request.session["mbox"], update_session=False)
-    resp.update(status="ok")
-    return ajax_simple_response(resp)
+    return render_to_json_response(resp)
 
 
 @login_required
@@ -85,8 +83,7 @@ def delete(request):
     message = ungettext("%(count)d message deleted",
                         "%(count)d messages deleted",
                         count) % {"count": count}
-    resp = dict(status="ok", respmsg=message)
-    return ajax_simple_response(resp)
+    return render_to_json_response(message)
 
 
 @login_required
@@ -102,10 +99,10 @@ def mark(request, name):
     except AttributeError:
         raise WebmailError(_("Unknown action"))
 
-    return ajax_simple_response(
-        dict(status="ok", action=status, mbox=name,
-             unseen=imapc.unseen_messages(name))
-    )
+    return render_to_json_response({
+        'action': status, 'mbox': name,
+        'unseen': imapc.unseen_messages(name)
+    })
 
 
 @login_required
@@ -115,9 +112,9 @@ def empty(request, name):
         raise WebmailError(_("Invalid request"))
     get_imapconnector(request).empty(name)
     content = "<div class='alert alert-info'>%s</div>" % _("Empty mailbox")
-    return ajax_simple_response(dict(
-        status="ok", listing=content, mailbox=name
-    ))
+    return render_to_json_response({
+        'listing': content, 'mailbox': name
+    })
 
 
 @login_required
@@ -125,7 +122,7 @@ def empty(request, name):
 def compact(request, name):
     imapc = get_imapconnector(request)
     imapc.compact(name)
-    return ajax_simple_response(dict(status="ok"))
+    return render_to_json_response({})
 
 
 @login_required
@@ -484,7 +481,7 @@ def viewmail(request):
 def submailboxes(request):
     topmailbox = request.GET.get('topmailbox', '')
     mboxes = get_imapconnector(request).getmboxes(request.user, topmailbox)
-    return ajax_simple_response(dict(status="ok", mboxes=mboxes))
+    return render_to_json_response(mboxes)
 
 
 @login_required
@@ -498,7 +495,7 @@ def check_unseen_messages(request):
     imapc = get_imapconnector(request)
     for mb in mboxes:
         counters[mb] = imapc.unseen_messages(mb)
-    return ajax_simple_response(dict(status="ok", counters=counters))
+    return render_to_json_response(counters)
 
 
 @login_required
@@ -570,6 +567,8 @@ def index(request):
             pass
 
     response.update(callback=action)
-    if not "status" in response:
-        response.update(status="ok")
-    return ajax_simple_response(response)
+    http_status = 200
+    if "status" in response:
+        del response['status']
+        http_status = 400
+    return render_to_json_response(response, status=http_status)
diff --git a/modoboa/lib/webutils.py b/modoboa/lib/webutils.py
index 7bbfbc136..8723b50c6 100644
--- a/modoboa/lib/webutils.py
+++ b/modoboa/lib/webutils.py
@@ -89,17 +89,6 @@ def ajax_response(request, status="ok", respmsg=None,
     return HttpResponse(simplejson.dumps(jsonctx), mimetype="application/json")
 
 
-def ajax_simple_response(content, **response_kwargs):
-    """Simple AJAX response
-
-    No extra formatting is done. The content is passed directly to simplejon.
-
-    :param content: the response's content (list, dict, string)
-    """
-    response_kwargs["content_type"] = "application/json"
-    return HttpResponse(simplejson.dumps(content), **response_kwargs)
-
-
 def render_to_json_response(context, **response_kwargs):
     """Simple shortcut to render a JSON response.
 
diff --git a/modoboa/static/js/confirmation.js b/modoboa/static/js/confirmation.js
index 3d6296be9..bf2fe35bd 100644
--- a/modoboa/static/js/confirmation.js
+++ b/modoboa/static/js/confirmation.js
@@ -89,7 +89,7 @@
              });
              $.ajax({
                  cache: false,
-                 method: this.options.method,
+                 type: this.options.method,
                  data: params,
                  url: this.$element.attr('href')
              }).done($.proxy(function(data) {
@@ -98,15 +98,7 @@
                      return;
                  }
                  window.location.reload();
-             }, this)).fail(function(jqxhr) {
-                 var data;
-                 try {
-                     data = $.parseJSON(jqxhr.responseText);
-                 } catch (e) {
-                     data = gettext('Internal Error');
-                 }
-                 $("body").notify("error", data);
-             });
+             }, this));
              this.box.remove();
          }
      };
diff --git a/modoboa/static/js/creation_wizard.js b/modoboa/static/js/creation_wizard.js
index a04e4bb82..e10985d64 100644
--- a/modoboa/static/js/creation_wizard.js
+++ b/modoboa/static/js/creation_wizard.js
@@ -38,41 +38,41 @@
             var $form = (this.options.formid) ? $('#' + this.options.formid) : $('form');
             var data = $form.serialize() + "&stepid=" + this.get_current_step_id();
 
-            $.ajax({type: 'POST', url: $form.attr("action"), data: data})
-                .done($.proxy(function(resp) {
-                    if (!last) {
-                        var stepid = resp.stepid + 1;
-                        $('input:text:visible:first').focus();
-                        this.set_current_title(resp.title);
-                        if (this.options.transition_callbacks[stepid] != undefined) {
-                            this.options.transition_callbacks[stepid]();
-                        }
-                        this.$element.carousel('next');
+            $.ajax({
+                type: 'POST', url: $form.attr("action"), data: data, global: false
+            }).done($.proxy(function(resp) {
+                if (!last) {
+                    var stepid = resp.stepid + 1;
+                    $('input:text:visible:first').focus();
+                    this.set_current_title(resp.title);
+                    if (this.options.transition_callbacks[stepid] != undefined) {
+                        this.options.transition_callbacks[stepid]();
+                    }
+                    this.$element.carousel('next');
+                } else {
+                    $("#modalbox").modal('hide').remove();
+                    if (this.options.success_callback != undefined) {
+                        this.options.success_callback(resp);
                     } else {
-                        $("#modalbox").modal('hide').remove();
-                        if (this.options.success_callback != undefined) {
-                            this.options.success_callback(resp);
-                        } else {
-                            window.location.reload();
-                        }
+                        window.location.reload();
                     }
-                }, this))
-                .fail($.proxy(function(jqxhr) {
-                    var resp = $.parseJSON(jqxhr.responseText);
-                    if (resp.stepid != undefined) {
-                        var stepid = resp.stepid;
-                        display_form_errors("step" + stepid, resp);
-                        if (this.options.error_callbacks[stepid] != undefined) {
-                            this.options.error_callbacks[stepid]();
-                        }
-                        $('input:text:visible:first').focus();
-                        if (resp.respmsg) {
-                            $(".modal-body").prepend(build_error_alert(resp.respmsg));
-                        }
-                        return;
+                }
+            }, this)).fail($.proxy(function(jqxhr) {
+                var resp = $.parseJSON(jqxhr.responseText);
+                if (resp.stepid != undefined) {
+                    var stepid = resp.stepid;
+                    display_form_errors("step" + stepid, resp);
+                    if (this.options.error_callbacks[stepid] != undefined) {
+                        this.options.error_callbacks[stepid]();
                     }
-                    $(".modal-body").prepend(build_error_alert(resp));
-                }, this));
+                    $('input:text:visible:first').focus();
+                    if (resp.respmsg) {
+                        $(".modal-body").prepend(build_error_alert(resp.respmsg));
+                    }
+                    return;
+                }
+                $(".modal-body").prepend(build_error_alert(resp));
+            }, this));
         },
 
         update_buttons: function() {
diff --git a/modoboa/static/js/global.js b/modoboa/static/js/global.js
index 5b28f076b..b899731c0 100644
--- a/modoboa/static/js/global.js
+++ b/modoboa/static/js/global.js
@@ -31,7 +31,10 @@ function modalbox(e, css, defhref, defcb, defclosecb) {
         $(href).modal('open');
         return;
     }
-    $.ajax({type: "GET", url: href}).done(function(data) {
+    $.ajax({
+        type: "GET",
+        url: href
+    }).done(function(data) {
         if (typeof data === "object") {
             /*
              * Compatibility with the old way...
@@ -70,9 +73,6 @@ function modalbox(e, css, defhref, defcb, defclosecb) {
         if (css != undefined) {
             $div.css(css);
         }
-    }).fail(function(jqxhr) {
-        var data = $.parseJSON(jqxhr.responseText);
-        $("body").notify("error", data);
     });
 }
 
@@ -168,6 +168,7 @@ function simple_ajax_form_post(e, options) {
     }
     $.ajax({
         type: "POST",
+        global: false,
         url: $form.attr("action"),
         data: args
     }).done(function(data) {
@@ -264,16 +265,11 @@ function simple_ajax_request(e, uoptions) {
     if (e != undefined) e.preventDefault();
     $.ajax({
         url: $this.attr("href"),
-        dataType: 'json',
-        success: function(data) {
-            if (data.status == "ok") {
-                if (options.ok_cb) options.ok_cb(data);
-                if (data.respmsg) {
-                    $("body").notify("success", data.respmsg, 2000);
-                }
-            } else {
-                $("body").notify("error", data.respmsg);
-            }
+        dataType: 'json'
+    }).done(function(data) {
+        if (options.ok_cb) options.ok_cb(data);
+        if (data) {
+            $("body").notify("success", data, 2000);
         }
     });
 }
@@ -304,8 +300,21 @@ function activate_widget(e) {
     }
 }
 
+/*
+ * Default error handler for AJAX requests.
+ */
+function default_ajax_error_handler(event, jqxhr, settings) {
+    try {
+        var data = $.parseJSON(jqxhr.responseText);
+    } catch (x) {
+        var data = gettext("Internal error");
+    }
+    $('body').notify('error', data);
+}
+
 $(document).ready(function() {
     $(document).ajaxSuccess(function(e, xhr, settings) { ajax_login_redirect(xhr); });
+    $(document).ajaxError(default_ajax_error_handler);
     $(document).on('click', 'a[data-toggle="ajaxmodal"]', modalbox);
     $(document).on('click', 'a[data-toggle="ajaxmodal-autowidth"]', modalbox_autowidth);
     $(document).on('click', '.activator', activate_widget);
diff --git a/modoboa/static/js/history.js b/modoboa/static/js/history.js
index d582219a1..2d21dca4f 100644
--- a/modoboa/static/js/history.js
+++ b/modoboa/static/js/history.js
@@ -227,20 +227,14 @@ History.prototype = {
         $.ajax({
             url: this.serialized,
             cache: false,
-            complete: $.proxy(function(XMLHttpRequest, textStatus) {
-                var resp;
-                try {
-                    resp = $.parseJSON(XMLHttpRequest.responseText);
-                } catch (e) {
-                    resp = { status: 'ko', respmsg: gettext('Internal Error') };
-                }
-                if (resp.status == "ko") {
-                    $("body").notify("error", resp.respmsg);
-                    return;
-                }
-                var callback = (resp.callback != undefined) ? resp.callback : "default";
-                this.callbacks[callback](resp);
-            }, this)
-        });
+            dataType: 'json'
+        }).done($.proxy(function(resp) {
+            var callback = (resp.callback != undefined) ? resp.callback : "default";
+
+            this.callbacks[callback](resp);
+            if (resp.respmsg) {
+                $("body").notify("success", resp.respmsg, 2000);
+            }
+        }, this));
     }
 };
\ No newline at end of file
diff --git a/modoboa/static/js/poller.js b/modoboa/static/js/poller.js
index 7beba47ea..acca1c4e5 100644
--- a/modoboa/static/js/poller.js
+++ b/modoboa/static/js/poller.js
@@ -62,19 +62,18 @@ Poller.prototype = {
         $.ajax({
             url: this.url + args,
             dataType: 'json',
-            success: function(data) {
-                poller.running_request = false;
-                if (data.status == "ok") {
-                    if (poller.options.success_cb) {
-                        poller.options.success_cb(data);
-                    }
-                    poller.reset();
-                } else {
-                    $("body").notify("error", data.respmsg);
-                    if (poller.options.error_cb) {
-                        poller.options.error_cb(data);
-                    }
-                }
+            global: false
+        }).done(function(data) {
+            poller.running_request = false;
+            if (poller.options.success_cb) {
+                poller.options.success_cb(data);
+            }
+            poller.reset();
+        }).fail(function(jqxhr) {
+            var data = $.parseJSON(jqxhr.responseText);
+            $("body").notify("error", data);
+            if (poller.options.error_cb) {
+                poller.options.error_cb(data);
             }
         });
     }