diff --git a/browser/components/CodeEditor.js b/browser/components/CodeEditor.js
index 667708a4..af546fbf 100644
--- a/browser/components/CodeEditor.js
+++ b/browser/components/CodeEditor.js
@@ -25,8 +25,9 @@ import TurndownService from 'turndown'
 import {languageMaps} from '../lib/CMLanguageList'
 import snippetManager from '../lib/SnippetManager'
 import {generateInEditor, tocExistsInEditor} from 'browser/lib/markdown-toc-generator'
+import Jsonlint from 'jsonlint-mod'
 import markdownlint from 'markdownlint'
-import ConfigManager from '../main/lib/ConfigManager'
+import ConfigManager, {DEFAULT_CONFIG} from '../main/lib/ConfigManager'
 
 CodeMirror.modeURL = '../node_modules/codemirror/mode/%N/%N.js'
 
@@ -41,13 +42,19 @@ function translateHotkey (hotkey) {
 
 const validatorOfMarkdown = (text, updateLinting) => {
   const config = ConfigManager.get()
+  let markdownlintRules = config.editor.customMarkdownLintConfig
+  try {
+    Jsonlint.parse(markdownlintRules)
+  } catch (error) {
+    markdownlintRules = DEFAULT_CONFIG.editor.customMarkdownLintConfig
+  }
+
   const lintOptions = {
     'strings': {
       'content': text
     },
-    'config': JSON.parse(config.editor.customMarkdownLintConfig)
+    'config': JSON.parse(markdownlintRules)
   }
-  console.log(config.editor.customMarkdownLintConfig)
 
   return markdownlint(lintOptions, (err, result) => {
     if (!err) {
diff --git a/browser/main/lib/ConfigManager.js b/browser/main/lib/ConfigManager.js
index 616fdc88..1d59d41d 100644
--- a/browser/main/lib/ConfigManager.js
+++ b/browser/main/lib/ConfigManager.js
@@ -60,7 +60,9 @@ export const DEFAULT_CONFIG = {
     frontMatterTitleField: 'title',
     spellcheck: false,
     enableSmartPaste: false,
-    customMarkdownLintConfig: ''
+    customMarkdownLintConfig: `{
+      "default": true
+    }`
   },
   preview: {
     fontSize: '14',
diff --git a/browser/main/modals/PreferencesModal/UiTab.js b/browser/main/modals/PreferencesModal/UiTab.js
index 310e1e59..d0b2026d 100644
--- a/browser/main/modals/PreferencesModal/UiTab.js
+++ b/browser/main/modals/PreferencesModal/UiTab.js
@@ -30,7 +30,7 @@ class UiTab extends React.Component {
   componentDidMount () {
     CodeMirror.autoLoadMode(this.codeMirrorInstance.getCodeMirror(), 'javascript')
     CodeMirror.autoLoadMode(this.customCSSCM.getCodeMirror(), 'css')
-    CodeMirror.autoLoadMode(this.customMarkdownLintConfigCM.getCodeMirror(), 'json')
+    CodeMirror.autoLoadMode(this.customMarkdownLintConfigCM.getCodeMirror(), 'javascript')
     this.customCSSCM.getCodeMirror().setSize('400px', '400px')
     this.customMarkdownLintConfigCM.getCodeMirror().setSize('400px', '400px')
     this.handleSettingDone = () => {
@@ -649,7 +649,10 @@ class UiTab extends React.Component {
                   value={config.editor.customMarkdownLintConfig}
                   options={{
                     lineNumbers: true,
-                    theme: codemirrorTheme
+                    mode: 'application/json',
+                    theme: codemirrorTheme,
+                    lint: true,
+                    gutters: ['CodeMirror-lint-markers']
                   }} />
               </div>
             </div>
diff --git a/lib/main.html b/lib/main.html
index 87a88e2d..c389956b 100644
--- a/lib/main.html
+++ b/lib/main.html
@@ -126,7 +126,9 @@
   <script src="../node_modules/codemirror/addon/dialog/dialog.js"></script>
   <script src="../node_modules/codemirror/addon/display/rulers.js"></script>
 
+  <script src="../node_modules/jsonlint-mod/lib/jsonlint.js"></script>
   <script src="../node_modules/codemirror/addon/lint/lint.js"></script>
+  <script src="../node_modules/codemirror/addon/lint/json-lint.js"></script>
 
   <script src="../node_modules/raphael/raphael.min.js"></script>
   <script src="../node_modules/flowchart.js/release/flowchart.min.js"></script>