diff --git a/lib/document_handler.js b/lib/document_handler.js
index f30defa..ba6ec68 100644
--- a/lib/document_handler.js
+++ b/lib/document_handler.js
@@ -24,7 +24,7 @@ DocumentHandler.prototype.handleGet = function(key, response, skipExpire) {
     else {
       winston.warn('document not found', { key: key });
       response.writeHead(404, { 'content-type': 'application/json' });
-      response.end(JSON.stringify({ message: 'document not found' }));
+      response.end(JSON.stringify({ message: 'Document not found.' }));
     }
   }, skipExpire);
 };
@@ -40,7 +40,7 @@ DocumentHandler.prototype.handleRawGet = function(key, response, skipExpire) {
     else {
       winston.warn('raw document not found', { key: key });
       response.writeHead(404, { 'content-type': 'application/json' });
-      response.end(JSON.stringify({ message: 'document not found' }));
+      response.end(JSON.stringify({ message: 'Document not found.' }));
     }
   }, skipExpire);
 };
@@ -58,7 +58,7 @@ DocumentHandler.prototype.handlePost = function(request, response) {
       _this.cancelled = true;
       winston.warn('document >maxLength', { maxLength: _this.maxLength });
       response.writeHead(400, { 'content-type': 'application/json' });
-      response.end(JSON.stringify({ message: 'document exceeds maximum length' }));
+      response.end(JSON.stringify({ message: 'Document exceeds maximum length.' }));
     }
   });
   request.on('end', function(end) {
@@ -72,7 +72,7 @@ DocumentHandler.prototype.handlePost = function(request, response) {
         else {
           winston.verbose('error adding document');
           response.writeHead(500, { 'content-type': 'application/json' });
-          response.end(JSON.stringify({ message: 'error adding document' }));
+          response.end(JSON.stringify({ message: 'Error adding document.' }));
         }
       });
     });
@@ -80,7 +80,7 @@ DocumentHandler.prototype.handlePost = function(request, response) {
   request.on('error', function(error) {
     winston.error('connection error: ' + error.message);
     response.writeHead(500, { 'content-type': 'application/json' });
-    response.end(JSON.stringify({ message: 'connection error' }));
+    response.end(JSON.stringify({ message: 'Connection error.' }));
   });
 };
 
diff --git a/static/application.css b/static/application.css
index 9a17b10..7587eed 100644
--- a/static/application.css
+++ b/static/application.css
@@ -110,7 +110,7 @@ textarea {
 	right: 0px;
 }
 
-#box3 {
+#box3, #messages li {
 	background: #173e48;
 	font-family: Helvetica, sans-serif;
 	font-size: 12px;
@@ -118,7 +118,7 @@ textarea {
 	padding: 10px 15px;
 }
 
-#box3 .label {
+#box3 .label, #messages li {
 	color: #fff;
 	font-weight: bold;
 }
@@ -147,3 +147,22 @@ textarea {
 #box2 .function.twitter { background-position: -153px top; }
 #box2 .function.enabled.twitter { background-position: -153px center; }
 #box2 .function.enabled.twitter:hover { background-position: -153px bottom; }
+
+#messages {
+	position:fixed;
+	top:0px;
+	right:138px;
+	margin:0;
+	padding:0;
+	width:400px;
+}
+
+#messages li {
+	background:rgba(23,62,72,0.8);
+	margin:0 auto;
+	list-style:none;
+}
+
+#messages li.error {
+	background:rgba(102,8,0,0.8);
+}
diff --git a/static/application.js b/static/application.js
index bd9f446..e21f447 100644
--- a/static/application.js
+++ b/static/application.js
@@ -57,12 +57,20 @@ haste_document.prototype.save = function(data, callback) {
       _this.locked = true;
       _this.key = res.key;
       var high = hljs.highlightAuto(data);
-      callback({
+      callback(null, {
         value: high.value,
         key: res.key,
         language: high.language,
         lineCount: data.split("\n").length
       });
+    },
+    error: function(res) {
+      try {
+        callback($.parseJSON(res.responseText));
+      }
+      catch (e) {
+        callback({message: 'Something went wrong!'});
+      }
     }
   });
 };
@@ -91,6 +99,15 @@ haste.prototype.setTitle = function(ext) {
   document.title = title;
 };
 
+// Show a message box
+haste.prototype.showMessage = function(msg, cls) {
+  var msgBox = $('<li class="'+(cls || 'info')+'">'+msg+'</li>');
+  $('#messages').prepend(msgBox);
+  setTimeout(function() {
+    msgBox.slideUp('fast', function() { $(this).remove(); });
+  }, 3000);
+};
+
 // Show the light key
 haste.prototype.lightKey = function() {
   this.configureKey(['new', 'save']);
@@ -209,8 +226,11 @@ haste.prototype.duplicateDocument = function() {
 // Lock the current document
 haste.prototype.lockDocument = function() {
   var _this = this;
-  this.doc.save(this.$textarea.val(), function(ret) {
-    if (ret) {
+  this.doc.save(this.$textarea.val(), function(err, ret) {
+    if (err) {
+      _this.showMessage(err.message, 'error');
+    }
+    else if (ret) {
       _this.$code.html(ret.value);
       _this.setTitle(ret.key);
       var file = '/' + ret.key;
diff --git a/static/application.min.js b/static/application.min.js
index 7f3ac9b..85a3a9b 100644
--- a/static/application.min.js
+++ b/static/application.min.js
@@ -1 +1 @@
-var haste_document=function(){this.locked=!1};haste_document.prototype.load=function(a,b,c){var d=this;$.ajax("/documents/"+a,{type:"get",dataType:"json",success:function(e){d.locked=!0,d.key=a,d.data=e.data;try{var f;c==="txt"?f={value:e.data}:c?f=hljs.highlight(c,e.data):f=hljs.highlightAuto(e.data)}catch(g){f=hljs.highlightAuto(e.data)}b({value:f.value,key:a,language:f.language||c,lineCount:e.data.split("\n").length})},error:function(a){b(!1)}})},haste_document.prototype.save=function(a,b){if(this.locked)return!1;this.data=a;var c=this;$.ajax("/documents",{type:"post",data:a,dataType:"json",success:function(d){c.locked=!0,c.key=d.key;var e=hljs.highlightAuto(a);b({value:e.value,key:d.key,language:e.language,lineCount:a.split("\n").length})}})};var haste=function(a,b){this.appName=a,this.baseUrl=window.location.href,this.$textarea=$("textarea"),this.$box=$("#box"),this.$code=$("#box code"),this.$linenos=$("#linenos"),this.options=b,this.configureShortcuts(),this.configureButtons(),b.twitter||$("#box2 .twitter").hide()};haste.prototype.setTitle=function(a){var b=a?this.appName+" - "+a:this.appName;document.title=b},haste.prototype.lightKey=function(){this.configureKey(["new","save"])},haste.prototype.fullKey=function(){this.configureKey(["new","duplicate","twitter","link"])},haste.prototype.configureKey=function(a){var b,c=0;$("#box2 .function").each(function(){b=$(this);for(c=0;c<a.length;c++)if(b.hasClass(a[c]))return b.addClass("enabled"),!0;b.removeClass("enabled")})},haste.prototype.newDocument=function(a){this.$box.hide(),this.doc=new haste_document,a||window.history.pushState(null,this.appName,"/"),this.setTitle(),this.lightKey(),this.$textarea.val("").show("fast",function(){this.focus()}),this.removeLineNumbers()},haste.extensionMap={rb:"ruby",py:"python",pl:"perl",php:"php",scala:"scala",go:"go",xml:"xml",html:"xml",htm:"xml",css:"css",js:"javascript",vbs:"vbscript",lua:"lua",pas:"delphi",java:"java",cpp:"cpp",cc:"cpp",m:"objectivec",vala:"vala",cs:"cs",sql:"sql",sm:"smalltalk",lisp:"lisp",ini:"ini",diff:"diff",bash:"bash",sh:"bash",tex:"tex",erl:"erlang",hs:"haskell",md:"markdown",txt:""},haste.prototype.lookupExtensionByType=function(a){for(var b in haste.extensionMap)if(haste.extensionMap[b]===a)return b;return a},haste.prototype.lookupTypeByExtension=function(a){return haste.extensionMap[a]||a},haste.prototype.addLineNumbers=function(a){var b="";for(var c=0;c<a;c++)b+=(c+1).toString()+"<br/>";$("#linenos").html(b)},haste.prototype.removeLineNumbers=function(){$("#linenos").html("&gt;")},haste.prototype.loadDocument=function(a){var b=a.split(".",2),c=this;c.doc=new haste_document,c.doc.load(b[0],function(a){a?(c.$code.html(a.value),c.setTitle(a.key),c.fullKey(),c.$textarea.val("").hide(),c.$box.show().focus(),c.addLineNumbers(a.lineCount)):c.newDocument()},this.lookupTypeByExtension(b[1]))},haste.prototype.duplicateDocument=function(){if(this.doc.locked){var a=this.doc.data;this.newDocument(),this.$textarea.val(a)}},haste.prototype.lockDocument=function(){var a=this;this.doc.save(this.$textarea.val(),function(b){if(b){a.$code.html(b.value),a.setTitle(b.key);var c="/"+b.key;b.language&&(c+="."+a.lookupExtensionByType(b.language)),window.history.pushState(null,a.appName+"-"+b.key,c),a.fullKey(),a.$textarea.val("").hide(),a.$box.show().focus(),a.addLineNumbers(b.lineCount)}})},haste.prototype.configureButtons=function(){var a=this;this.buttons=[{$where:$("#box2 .save"),label:"Save",shortcutDescription:"control + s",shortcut:function(a){return a.ctrlKey&&a.keyCode===83},action:function(){a.$textarea.val().replace(/^\s+|\s+$/g,"")!==""&&a.lockDocument()}},{$where:$("#box2 .new"),label:"New",shortcut:function(a){return a.ctrlKey&&a.keyCode===78},shortcutDescription:"control + n",action:function(){a.newDocument(!a.doc.key)}},{$where:$("#box2 .duplicate"),label:"Duplicate & Edit",shortcut:function(b){return a.doc.locked&&b.ctrlKey&&b.keyCode===68},shortcutDescription:"control + d",action:function(){a.duplicateDocument()}},{$where:$("#box2 .twitter"),label:"Twitter",shortcut:function(b){return a.options.twitter&&a.doc.locked&&b.ctrlKey&&b.keyCode==84},shortcutDescription:"control + t",action:function(){window.open("https://twitter.com/share?url="+encodeURI(window.location.href))}}];for(var b=0;b<this.buttons.length;b++)this.configureButton(this.buttons[b])},haste.prototype.configureButton=function(a){a.$where.click(function(b){b.preventDefault(),!a.clickDisabled&&$(this).hasClass("enabled")&&a.action()}),a.$where.mouseenter(function(b){$("#box3 .label").text(a.label),$("#box3 .shortcut").text(a.shortcutDescription||""),$("#box3").show(),$(this).append($("#pointer").remove().show())}),a.$where.mouseleave(function(a){$("#box3").hide(),$("#pointer").hide()})},haste.prototype.configureShortcuts=function(){var a=this;$(document.body).keydown(function(b){var c;for(var d=0;d<a.buttons.length;d++){c=a.buttons[d];if(c.shortcut&&c.shortcut(b)){b.preventDefault(),c.action();return}}})},$(function(){$("textarea").keydown(function(a){if(a.keyCode===9){a.preventDefault();var b="  ";if(document.selection)this.focus(),sel=document.selection.createRange(),sel.text=b,this.focus();else if(this.selectionStart||this.selectionStart=="0"){var c=this.selectionStart,d=this.selectionEnd,e=this.scrollTop;this.value=this.value.substring(0,c)+b+this.value.substring(d,this.value.length),this.focus(),this.selectionStart=c+b.length,this.selectionEnd=c+b.length,this.scrollTop=e}else this.value+=b,this.focus()}})})
\ No newline at end of file
+var haste_document=function(){this.locked=!1};haste_document.prototype.load=function(a,b,c){var d=this;$.ajax("/documents/"+a,{type:"get",dataType:"json",success:function(e){d.locked=!0,d.key=a,d.data=e.data;try{var f;c==="txt"?f={value:e.data}:c?f=hljs.highlight(c,e.data):f=hljs.highlightAuto(e.data)}catch(g){f=hljs.highlightAuto(e.data)}b({value:f.value,key:a,language:f.language||c,lineCount:e.data.split("\n").length})},error:function(a){b(!1)}})},haste_document.prototype.save=function(a,b){if(this.locked)return!1;this.data=a;var c=this;$.ajax("/documents",{type:"post",data:a,dataType:"json",success:function(d){c.locked=!0,c.key=d.key;var e=hljs.highlightAuto(a);b(null,{value:e.value,key:d.key,language:e.language,lineCount:a.split("\n").length})},error:function(a){try{b($.parseJSON(a.responseText))}catch(c){b({message:"Something went wrong!"})}}})};var haste=function(a,b){this.appName=a,this.baseUrl=window.location.href,this.$textarea=$("textarea"),this.$box=$("#box"),this.$code=$("#box code"),this.$linenos=$("#linenos"),this.options=b,this.configureShortcuts(),this.configureButtons(),b.twitter||$("#box2 .twitter").hide()};haste.prototype.setTitle=function(a){var b=a?this.appName+" - "+a:this.appName;document.title=b},haste.prototype.showMessage=function(a,b){var c=$('<li class="'+(b||"info")+'">'+a+"</li>");$("#messages").prepend(c),setTimeout(function(){c.slideUp("fast",function(){$(this).remove()})},3e3)},haste.prototype.lightKey=function(){this.configureKey(["new","save"])},haste.prototype.fullKey=function(){this.configureKey(["new","duplicate","twitter","link"])},haste.prototype.configureKey=function(a){var b,c=0;$("#box2 .function").each(function(){b=$(this);for(c=0;c<a.length;c++)if(b.hasClass(a[c]))return b.addClass("enabled"),!0;b.removeClass("enabled")})},haste.prototype.newDocument=function(a){this.$box.hide(),this.doc=new haste_document,a||window.history.pushState(null,this.appName,"/"),this.setTitle(),this.lightKey(),this.$textarea.val("").show("fast",function(){this.focus()}),this.removeLineNumbers()},haste.extensionMap={rb:"ruby",py:"python",pl:"perl",php:"php",scala:"scala",go:"go",xml:"xml",html:"xml",htm:"xml",css:"css",js:"javascript",vbs:"vbscript",lua:"lua",pas:"delphi",java:"java",cpp:"cpp",cc:"cpp",m:"objectivec",vala:"vala",cs:"cs",sql:"sql",sm:"smalltalk",lisp:"lisp",ini:"ini",diff:"diff",bash:"bash",sh:"bash",tex:"tex",erl:"erlang",hs:"haskell",md:"markdown",txt:""},haste.prototype.lookupExtensionByType=function(a){for(var b in haste.extensionMap)if(haste.extensionMap[b]===a)return b;return a},haste.prototype.lookupTypeByExtension=function(a){return haste.extensionMap[a]||a},haste.prototype.addLineNumbers=function(a){var b="";for(var c=0;c<a;c++)b+=(c+1).toString()+"<br/>";$("#linenos").html(b)},haste.prototype.removeLineNumbers=function(){$("#linenos").html("&gt;")},haste.prototype.loadDocument=function(a){var b=a.split(".",2),c=this;c.doc=new haste_document,c.doc.load(b[0],function(a){a?(c.$code.html(a.value),c.setTitle(a.key),c.fullKey(),c.$textarea.val("").hide(),c.$box.show().focus(),c.addLineNumbers(a.lineCount)):c.newDocument()},this.lookupTypeByExtension(b[1]))},haste.prototype.duplicateDocument=function(){if(this.doc.locked){var a=this.doc.data;this.newDocument(),this.$textarea.val(a)}},haste.prototype.lockDocument=function(){var a=this;this.doc.save(this.$textarea.val(),function(b,c){if(b)a.showMessage(b.message,"error");else if(c){a.$code.html(c.value),a.setTitle(c.key);var d="/"+c.key;c.language&&(d+="."+a.lookupExtensionByType(c.language)),window.history.pushState(null,a.appName+"-"+c.key,d),a.fullKey(),a.$textarea.val("").hide(),a.$box.show().focus(),a.addLineNumbers(c.lineCount)}})},haste.prototype.configureButtons=function(){var a=this;this.buttons=[{$where:$("#box2 .save"),label:"Save",shortcutDescription:"control + s",shortcut:function(a){return a.ctrlKey&&a.keyCode===83},action:function(){a.$textarea.val().replace(/^\s+|\s+$/g,"")!==""&&a.lockDocument()}},{$where:$("#box2 .new"),label:"New",shortcut:function(a){return a.ctrlKey&&a.keyCode===78},shortcutDescription:"control + n",action:function(){a.newDocument(!a.doc.key)}},{$where:$("#box2 .duplicate"),label:"Duplicate & Edit",shortcut:function(b){return a.doc.locked&&b.ctrlKey&&b.keyCode===68},shortcutDescription:"control + d",action:function(){a.duplicateDocument()}},{$where:$("#box2 .twitter"),label:"Twitter",shortcut:function(b){return a.options.twitter&&a.doc.locked&&b.ctrlKey&&b.keyCode==84},shortcutDescription:"control + t",action:function(){window.open("https://twitter.com/share?url="+encodeURI(window.location.href))}}];for(var b=0;b<this.buttons.length;b++)this.configureButton(this.buttons[b])},haste.prototype.configureButton=function(a){a.$where.click(function(b){b.preventDefault(),!a.clickDisabled&&$(this).hasClass("enabled")&&a.action()}),a.$where.mouseenter(function(b){$("#box3 .label").text(a.label),$("#box3 .shortcut").text(a.shortcutDescription||""),$("#box3").show(),$(this).append($("#pointer").remove().show())}),a.$where.mouseleave(function(a){$("#box3").hide(),$("#pointer").hide()})},haste.prototype.configureShortcuts=function(){var a=this;$(document.body).keydown(function(b){var c;for(var d=0;d<a.buttons.length;d++){c=a.buttons[d];if(c.shortcut&&c.shortcut(b)){b.preventDefault(),c.action();return}}})},$(function(){$("textarea").keydown(function(a){if(a.keyCode===9){a.preventDefault();var b="  ";if(document.selection)this.focus(),sel=document.selection.createRange(),sel.text=b,this.focus();else if(this.selectionStart||this.selectionStart=="0"){var c=this.selectionStart,d=this.selectionEnd,e=this.scrollTop;this.value=this.value.substring(0,c)+b+this.value.substring(d,this.value.length),this.focus(),this.selectionStart=c+b.length,this.selectionEnd=c+b.length,this.scrollTop=e}else this.value+=b,this.focus()}})})
\ No newline at end of file
diff --git a/static/index.html b/static/index.html
index d9b7d2d..57395f2 100644
--- a/static/index.html
+++ b/static/index.html
@@ -39,6 +39,7 @@
 	</head>
 
 	<body>
+		<ul id="messages"></ul>
 
 		<div id="key">
 		  <div id="pointer" style="display:none;"></div>