diff --git a/MultiMC.cpp b/MultiMC.cpp
index 71d0e5a7..24cdd077 100644
--- a/MultiMC.cpp
+++ b/MultiMC.cpp
@@ -8,6 +8,7 @@
 #include <QLibraryInfo>
 #include <QMessageBox>
 #include <QStringList>
+#include <QDesktopServices>
 
 #include "gui/dialogs/VersionSelectDialog.h"
 #include "logic/lists/InstanceList.h"
@@ -382,6 +383,9 @@ void MultiMC::initGlobalSettings()
 	m_settings->registerSetting(new Setting("CentralModsDir", "mods"));
 	m_settings->registerSetting(new Setting("LWJGLDir", "lwjgl"));
 
+	// Editors
+	m_settings->registerSetting(new Setting("JsonEditor", QString()));
+
 	// Console
 	m_settings->registerSetting(new Setting("ShowConsole", true));
 	m_settings->registerSetting(new Setting("AutoCloseConsole", true));
@@ -550,4 +554,18 @@ QString MultiMC::getExitUpdatePath() const
 	return m_updateOnExitPath;
 }
 
+void MultiMC::openJsonEditor(const QString &filename)
+{
+	const QString file = QDir::current().absoluteFilePath(filename);
+	if (m_settings->get("JsonEditor").toString().isEmpty())
+	{
+		QDesktopServices::openUrl(QUrl::fromLocalFile(file));
+	}
+	else
+	{
+		QProcess::startDetached(m_settings->get("JsonEditor").toString(),
+								QStringList() << file);
+	}
+}
+
 #include "MultiMC.moc"
diff --git a/MultiMC.h b/MultiMC.h
index 4a33fb69..17113181 100644
--- a/MultiMC.h
+++ b/MultiMC.h
@@ -6,7 +6,6 @@
 #include "logger/QsLog.h"
 #include "logger/QsLogDest.h"
 
-
 class MinecraftVersionList;
 class LWJGLVersionList;
 class HttpMetaCache;
@@ -101,12 +100,12 @@ public:
 	/*!
 	 * Installs update from the given update files directory.
 	 */
-	void installUpdates(const QString& updateFilesDir, bool restartOnFinish=false);
+	void installUpdates(const QString &updateFilesDir, bool restartOnFinish = false);
 
 	/*!
 	 * Sets MultiMC to install updates from the given directory when it exits.
 	 */
-	void setUpdateOnExit(const QString& updateFilesDir);
+	void setUpdateOnExit(const QString &updateFilesDir);
 
 	/*!
 	 * Gets the path to install updates from on exit.
@@ -114,6 +113,12 @@ public:
 	 */
 	QString getExitUpdatePath() const;
 
+	/*!
+	 * Opens a json file using either a system default editor, or, if note empty, the editor
+	 * specified in the settings
+	 */
+	void openJsonEditor(const QString &filename);
+
 private:
 	void initLogger();
 
diff --git a/gui/dialogs/OneSixModEditDialog.cpp b/gui/dialogs/OneSixModEditDialog.cpp
index d8b84d3e..e575c868 100644
--- a/gui/dialogs/OneSixModEditDialog.cpp
+++ b/gui/dialogs/OneSixModEditDialog.cpp
@@ -97,6 +97,7 @@ void OneSixModEditDialog::updateVersionControls()
 	ui->revertBtn->setEnabled(customVersion);
 	ui->forgeBtn->setEnabled(true);
 	ui->liteloaderBtn->setEnabled(LiteLoaderInstaller(m_inst->intendedVersionId()).canApply());
+	ui->customEditorBtn->setEnabled(customVersion);
 }
 
 void OneSixModEditDialog::disableVersionControls()
@@ -105,6 +106,7 @@ void OneSixModEditDialog::disableVersionControls()
 	ui->revertBtn->setEnabled(false);
 	ui->forgeBtn->setEnabled(false);
 	ui->liteloaderBtn->setEnabled(false);
+	ui->customEditorBtn->setEnabled(false);
 }
 
 void OneSixModEditDialog::on_customizeBtn_clicked()
@@ -134,6 +136,14 @@ void OneSixModEditDialog::on_revertBtn_clicked()
 	}
 }
 
+void OneSixModEditDialog::on_customEditorBtn_clicked()
+{
+	if (m_inst->versionIsCustom())
+	{
+		MMC->openJsonEditor(m_inst->instanceRoot() + "/custom.json");
+	}
+}
+
 void OneSixModEditDialog::on_forgeBtn_clicked()
 {
 	VersionSelectDialog vselect(MMC->forgelist().get(), tr("Select Forge version"), this);
diff --git a/gui/dialogs/OneSixModEditDialog.h b/gui/dialogs/OneSixModEditDialog.h
index 09bd7946..2510c59c 100644
--- a/gui/dialogs/OneSixModEditDialog.h
+++ b/gui/dialogs/OneSixModEditDialog.h
@@ -47,6 +47,7 @@ slots:
 	void on_liteloaderBtn_clicked();
 	void on_customizeBtn_clicked();
 	void on_revertBtn_clicked();
+	void on_customEditorBtn_clicked();
 	void updateVersionControls();
 	void disableVersionControls();
 
diff --git a/gui/dialogs/OneSixModEditDialog.ui b/gui/dialogs/OneSixModEditDialog.ui
index ad20cd73..899e0cbf 100644
--- a/gui/dialogs/OneSixModEditDialog.ui
+++ b/gui/dialogs/OneSixModEditDialog.ui
@@ -143,6 +143,20 @@
            </property>
           </widget>
          </item>
+         <item>
+          <widget class="Line" name="line_2">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QPushButton" name="customEditorBtn">
+           <property name="text">
+            <string>Open custom.json</string>
+           </property>
+          </widget>
+         </item>
          <item>
           <spacer name="verticalSpacer_7">
            <property name="orientation">
diff --git a/gui/dialogs/SettingsDialog.cpp b/gui/dialogs/SettingsDialog.cpp
index 131cb5c3..a95a8e83 100644
--- a/gui/dialogs/SettingsDialog.cpp
+++ b/gui/dialogs/SettingsDialog.cpp
@@ -125,6 +125,23 @@ void SettingsDialog::on_lwjglDirBrowseBtn_clicked()
 	}
 }
 
+void SettingsDialog::on_jsonEditorBrowseBtn_clicked()
+{
+	QString raw_file = QFileDialog::getOpenFileName(
+		this, tr("JSON Editor"),
+		ui->jsonEditorTextBox->text().isEmpty()
+			? QStandardPaths::standardLocations(QStandardPaths::ApplicationsLocation).first()
+			: ui->jsonEditorTextBox->text());
+	QString cooked_file = NormalizePath(raw_file);
+
+	// it has to exist and be an executable
+	if (!cooked_file.isEmpty() && QFileInfo(cooked_file).exists() &&
+		QFileInfo(cooked_file).isExecutable())
+	{
+		ui->jsonEditorTextBox->setText(cooked_file);
+	}
+}
+
 void SettingsDialog::on_maximizedCheckBox_clicked(bool checked)
 {
 	Q_UNUSED(checked);
@@ -172,6 +189,18 @@ void SettingsDialog::applySettings(SettingsObject *s)
 	s->set("CentralModsDir", ui->modsDirTextBox->text());
 	s->set("LWJGLDir", ui->lwjglDirTextBox->text());
 
+	// Editors
+	QString jsonEditor = ui->jsonEditorTextBox->text();
+	if (!jsonEditor.isEmpty() && (!QFileInfo(jsonEditor).exists() || !QFileInfo(jsonEditor).isExecutable()))
+	{
+		QString found = QStandardPaths::findExecutable(jsonEditor);
+		if (!found.isEmpty())
+		{
+			jsonEditor = found;
+		}
+	}
+	s->set("JsonEditor", jsonEditor);
+
 	// Console
 	s->set("ShowConsole", ui->showConsoleCheck->isChecked());
 	s->set("AutoCloseConsole", ui->autoCloseConsoleCheck->isChecked());
@@ -226,6 +255,9 @@ void SettingsDialog::loadSettings(SettingsObject *s)
 	ui->modsDirTextBox->setText(s->get("CentralModsDir").toString());
 	ui->lwjglDirTextBox->setText(s->get("LWJGLDir").toString());
 
+	// Editors
+	ui->jsonEditorTextBox->setText(s->get("JsonEditor").toString());
+
 	// Console
 	ui->showConsoleCheck->setChecked(s->get("ShowConsole").toBool());
 	ui->autoCloseConsoleCheck->setChecked(s->get("AutoCloseConsole").toBool());
diff --git a/gui/dialogs/SettingsDialog.h b/gui/dialogs/SettingsDialog.h
index 36fc4797..01357c91 100644
--- a/gui/dialogs/SettingsDialog.h
+++ b/gui/dialogs/SettingsDialog.h
@@ -55,6 +55,8 @@ slots:
 
 	void on_lwjglDirBrowseBtn_clicked();
 
+	void on_jsonEditorBrowseBtn_clicked();
+
 	void on_maximizedCheckBox_clicked(bool checked);
 
 	void on_buttonBox_accepted();
diff --git a/gui/dialogs/SettingsDialog.ui b/gui/dialogs/SettingsDialog.ui
index 4d06d1f8..ca8c7391 100644
--- a/gui/dialogs/SettingsDialog.ui
+++ b/gui/dialogs/SettingsDialog.ui
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>526</width>
-    <height>599</height>
+    <height>628</height>
    </rect>
   </property>
   <property name="sizePolicy">
@@ -39,7 +39,7 @@
       <attribute name="title">
        <string>General</string>
       </attribute>
-      <layout class="QVBoxLayout" name="generalTabLayout">
+      <layout class="QVBoxLayout" name="verticalLayout">
        <item>
         <widget class="QGroupBox" name="sortingModeBox">
          <property name="enabled">
@@ -236,6 +236,36 @@
          </layout>
         </widget>
        </item>
+       <item>
+        <widget class="QGroupBox" name="editorsBox">
+         <property name="title">
+          <string>External Editors (leave empty for system default)</string>
+         </property>
+         <layout class="QGridLayout" name="foldersBoxLayout_2">
+          <item row="0" column="1">
+           <widget class="QLineEdit" name="jsonEditorTextBox">
+            <property name="clearButtonEnabled">
+             <bool>true</bool>
+            </property>
+           </widget>
+          </item>
+          <item row="0" column="0">
+           <widget class="QLabel" name="labelJsonEditor">
+            <property name="text">
+             <string>JSON Editor:</string>
+            </property>
+           </widget>
+          </item>
+          <item row="0" column="2">
+           <widget class="QToolButton" name="jsonEditorBrowseBtn">
+            <property name="text">
+             <string>...</string>
+            </property>
+           </widget>
+          </item>
+         </layout>
+        </widget>
+       </item>
        <item>
         <spacer name="generalTabSpacer">
          <property name="orientation">