diff --git a/converse.js b/converse.js
index 0969caf26..b3d02f687 100644
--- a/converse.js
+++ b/converse.js
@@ -309,12 +309,14 @@
             cache_otr_key: false,
             csi_waiting_time: 0, // Support for XEP-0352. Seconds before client is considered idle and CSI is sent out.
             debug: false,
+            default_domain: undefined,
             domain_placeholder: __(" e.g. conversejs.org"),  // Placeholder text shown in the domain input on the registration form
             expose_rid_and_sid: false,
             forward_messages: false,
             hide_muc_server: false,
             hide_offline_users: false,
             jid: undefined,
+            locked_domain: undefined,
             keepalive: false,
             message_archiving: 'never', // Supported values are 'always', 'never', 'roster' (See https://xmpp.org/extensions/xep-0313.html#prefs )
             message_carbons: false, // Support for XEP-280
@@ -6015,7 +6017,7 @@
                         'label_password': __('Password:'),
                         'label_anon_login': __('Click here to log in anonymously'),
                         'label_login': __('Log In'),
-                        'placeholder_username': __('user@server'),
+                        'placeholder_username': (converse.locked_domain || converse.default_domain) && __('Username') || __('user@server'),
                         'placeholder_password': __('password')
                     })
                 ));
@@ -6053,6 +6055,11 @@
                     $pw_input.addClass('error');
                 }
                 if (errors) { return; }
+                if (converse.locked_domain) {
+                    jid = Strophe.escapeNode(jid) + '@' + converse.locked_domain;
+                } else if (converse.default_domain && jid.indexOf('@') === -1) {
+                    jid = jid + '@' + converse.default_domain;
+                }
                 this.connect($form, jid, password);
                 return false;
             },
diff --git a/docs/CHANGES.md b/docs/CHANGES.md
index b47b0fd0c..c4307d61e 100644
--- a/docs/CHANGES.md
+++ b/docs/CHANGES.md
@@ -5,6 +5,8 @@
 - #352 When the user has manually scrolled up in a chat window, don't scroll
   down on chat event notifications. [jcbrand]
 - #524 Added `auto_join_on_invite` parameter for automatically joining chatrooms. [ben]
+- #520 Set specific domain. Two new options [default_domain](https://conversejs.org/docs/html/configuration.html#default_domain)
+  and [locked_domain](https://conversejs.org/docs/html/configuration.html#locked_domain). [jcbrand]
 - #521 Not sending presence when connecting after disconnection. [jcbrand]
 - #535 Messages not received when room with mixed-case JID is used. [jcbrand]
 - #536 Presence not sent out (in cases where it should) after page refresh. [jcbrand]
diff --git a/docs/source/configuration.rst b/docs/source/configuration.rst
index 952ed42d0..56f0170b5 100644
--- a/docs/source/configuration.rst
+++ b/docs/source/configuration.rst
@@ -319,6 +319,21 @@ debug
 
 If set to true, debugging output will be logged to the browser console.
 
+default_domain
+--------------
+
+* Default:  ``undefined``
+
+Specify a domain to act as the default for user JIDs. This allows users to log
+in with only the username part of their JID, instead of the full JID.
+
+For example, if ``default_domain`` is ``example.org``, then the user:
+``johnny@example.org`` can log in with only ``johnny``.
+
+JIDs with other domains are still allowed but need to be provided in full.
+To specify only one domain and disallow other domains, see the `locked_domain`_
+option.
+
 domain_placeholder
 ------------------
 
@@ -476,7 +491,12 @@ If no locale is matching available locales, the default is ``en``.
 Specify the locale/language. The language must be in the ``locales`` object. Refer to
 ``./locale/locales.js`` to see which locales are supported.
 
-.. _`play-sounds`:
+locked_domain
+-------------
+
+* Default:  ``undefined``
+
+Similar to `default_domain`_ but no other domains are allowed.
 
 ping_interval
 -------------
@@ -489,6 +509,8 @@ You need to set the value to any positive value to enable this functionality.
 
 If you set this value to ``0`` or any negative value, il will disable this functionality.
 
+.. _`play-sounds`:
+
 play_sounds
 -----------