diff --git a/buildconfig/BuildConfig.h b/buildconfig/BuildConfig.h
index 6304387cb..c1d347087 100644
--- a/buildconfig/BuildConfig.h
+++ b/buildconfig/BuildConfig.h
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
+ *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
  *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
@@ -139,6 +140,7 @@ public:
     QString LEGACY_FTB_CDN_BASE_URL = "https://dist.creeper.host/FTB2/";
 
     QString ATL_DOWNLOAD_SERVER_URL = "https://download.nodecdn.net/containers/atl/";
+    QString ATL_API_BASE_URL = "https://api.atlauncher.com/v1/";
 
     QString TECHNIC_API_BASE_URL = "https://api.technicpack.net/";
     /**
diff --git a/launcher/CMakeLists.txt b/launcher/CMakeLists.txt
index 6ed86726b..e60c4d45a 100644
--- a/launcher/CMakeLists.txt
+++ b/launcher/CMakeLists.txt
@@ -557,6 +557,8 @@ set(ATLAUNCHER_SOURCES
     modplatform/atlauncher/ATLPackInstallTask.h
     modplatform/atlauncher/ATLPackManifest.cpp
     modplatform/atlauncher/ATLPackManifest.h
+    modplatform/atlauncher/ATLShareCode.cpp
+    modplatform/atlauncher/ATLShareCode.h
 )
 
 add_unit_test(Index
diff --git a/launcher/modplatform/atlauncher/ATLShareCode.cpp b/launcher/modplatform/atlauncher/ATLShareCode.cpp
new file mode 100644
index 000000000..59030c873
--- /dev/null
+++ b/launcher/modplatform/atlauncher/ATLShareCode.cpp
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "ATLShareCode.h"
+
+#include "Json.h"
+
+namespace ATLauncher {
+
+static void loadShareCodeMod(ShareCodeMod& m, QJsonObject& obj)
+{
+    m.selected = Json::requireBoolean(obj, "selected");
+    m.name = Json::requireString(obj, "name");
+}
+
+static void loadShareCode(ShareCode& c, QJsonObject& obj)
+{
+    c.pack = Json::requireString(obj, "pack");
+    c.version = Json::requireString(obj, "version");
+
+    auto mods = Json::requireObject(obj, "mods");
+    auto optional = Json::requireArray(mods, "optional");
+    for (const auto modRaw : optional) {
+        auto modObj = Json::requireObject(modRaw);
+        ShareCodeMod mod;
+        loadShareCodeMod(mod, modObj);
+        c.mods.append(mod);
+    }
+}
+
+void loadShareCodeResponse(ShareCodeResponse& r, QJsonObject& obj)
+{
+    r.error = Json::requireBoolean(obj, "error");
+    r.code = Json::requireInteger(obj, "code");
+
+    if (obj.contains("message") && !obj.value("message").isNull())
+        r.message = Json::requireString(obj, "message");
+
+    if (!r.error) {
+        auto dataRaw = Json::requireObject(obj, "data");
+        loadShareCode(r.data, dataRaw);
+    }
+}
+
+}
diff --git a/launcher/modplatform/atlauncher/ATLShareCode.h b/launcher/modplatform/atlauncher/ATLShareCode.h
new file mode 100644
index 000000000..88c30c98e
--- /dev/null
+++ b/launcher/modplatform/atlauncher/ATLShareCode.h
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QString>
+#include <QVector>
+#include <QJsonObject>
+
+namespace ATLauncher {
+
+struct ShareCodeMod {
+    bool selected;
+    QString name;
+};
+
+struct ShareCode {
+    QString pack;
+    QString version;
+    QVector<ShareCodeMod> mods;
+};
+
+struct ShareCodeResponse {
+    bool error;
+    int code;
+    QString message;
+    ShareCode data;
+};
+
+void loadShareCodeResponse(ShareCodeResponse& r, QJsonObject& obj);
+
+}
diff --git a/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.cpp b/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.cpp
index ac3869dca..39ecf1798 100644
--- a/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.cpp
+++ b/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.cpp
@@ -1,30 +1,56 @@
+// SPDX-License-Identifier: GPL-3.0-only
 /*
- * Copyright 2021 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2021 Jamie Mansfield <jmansfield@cadixdev.org>
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "AtlOptionalModDialog.h"
 #include "ui_AtlOptionalModDialog.h"
 
+#include <QInputDialog>
+#include <QMessageBox>
+#include "BuildConfig.h"
+#include "Json.h"
+#include "modplatform/atlauncher/ATLShareCode.h"
+#include "Application.h"
+
 AtlOptionalModListModel::AtlOptionalModListModel(QWidget *parent, QVector<ATLauncher::VersionMod> mods)
     : QAbstractListModel(parent), m_mods(mods) {
-
     // fill mod index
     for (int i = 0; i < m_mods.size(); i++) {
         auto mod = m_mods.at(i);
         m_index[mod.name] = i;
     }
+
     // set initial state
     for (int i = 0; i < m_mods.size(); i++) {
         auto mod = m_mods.at(i);
@@ -77,7 +103,7 @@ QVariant AtlOptionalModListModel::data(const QModelIndex &index, int role) const
         }
     }
 
-    return QVariant();
+    return {};
 }
 
 bool AtlOptionalModListModel::setData(const QModelIndex &index, const QVariant &value, int role) {
@@ -104,7 +130,7 @@ QVariant AtlOptionalModListModel::headerData(int section, Qt::Orientation orient
         }
     }
 
-    return QVariant();
+    return {};
 }
 
 Qt::ItemFlags AtlOptionalModListModel::flags(const QModelIndex &index) const {
@@ -115,6 +141,69 @@ Qt::ItemFlags AtlOptionalModListModel::flags(const QModelIndex &index) const {
     return flags;
 }
 
+void AtlOptionalModListModel::useShareCode(const QString& code) {
+    m_jobPtr.reset(new NetJob("Atl::Request", APPLICATION->network()));
+    auto url = QString(BuildConfig.ATL_API_BASE_URL + "share-codes/" + code);
+    m_jobPtr->addNetAction(Net::Download::makeByteArray(QUrl(url), &m_response));
+
+    connect(m_jobPtr.get(), &NetJob::succeeded,
+            this, &AtlOptionalModListModel::shareCodeSuccess);
+    connect(m_jobPtr.get(), &NetJob::failed,
+            this, &AtlOptionalModListModel::shareCodeFailure);
+
+    m_jobPtr->start();
+}
+
+void AtlOptionalModListModel::shareCodeSuccess() {
+    m_jobPtr.reset();
+
+    QJsonParseError parse_error {};
+    auto doc = QJsonDocument::fromJson(m_response, &parse_error);
+    if (parse_error.error != QJsonParseError::NoError) {
+        qWarning() << "Error while parsing JSON response from ATL at " << parse_error.offset << " reason: " << parse_error.errorString();
+        qWarning() << m_response;
+        return;
+    }
+    auto obj = doc.object();
+
+    ATLauncher::ShareCodeResponse response;
+    try {
+        ATLauncher::loadShareCodeResponse(response, obj);
+    }
+    catch (const JSONValidationError& e) {
+        qDebug() << QString::fromUtf8(m_response);
+        qWarning() << "Error while reading response from ATLauncher: " << e.cause();
+        return;
+    }
+
+    if (response.error) {
+        // fixme: plumb in an error message
+        qWarning() << "ATLauncher API Response Error" << response.message;
+        return;
+    }
+
+    // FIXME: verify pack and version, error if not matching.
+
+    // Clear the current selection
+    for (const auto& mod : m_mods) {
+        m_selection[mod.name] = false;
+    }
+
+    // Make the selections, as per the share code.
+    for (const auto& mod : response.data.mods) {
+        m_selection[mod.name] = mod.selected;
+    }
+
+    emit dataChanged(AtlOptionalModListModel::index(0, EnabledColumn),
+                     AtlOptionalModListModel::index(m_mods.size() - 1, EnabledColumn));
+}
+
+void AtlOptionalModListModel::shareCodeFailure(const QString& reason) {
+    m_jobPtr.reset();
+
+    // fixme: plumb in an error message
+}
+
 void AtlOptionalModListModel::selectRecommended() {
     for (const auto& mod : m_mods) {
         m_selection[mod.name] = mod.recommended;
@@ -212,6 +301,8 @@ AtlOptionalModDialog::AtlOptionalModDialog(QWidget *parent, QVector<ATLauncher::
     ui->treeView->header()->setSectionResizeMode(
             AtlOptionalModListModel::DescriptionColumn, QHeaderView::Stretch);
 
+    connect(ui->shareCodeButton, &QPushButton::pressed,
+            this, &AtlOptionalModDialog::useShareCode);
     connect(ui->selectRecommendedButton, &QPushButton::pressed,
             listModel, &AtlOptionalModListModel::selectRecommended);
     connect(ui->clearAllButton, &QPushButton::pressed,
@@ -223,3 +314,30 @@ AtlOptionalModDialog::AtlOptionalModDialog(QWidget *parent, QVector<ATLauncher::
 AtlOptionalModDialog::~AtlOptionalModDialog() {
     delete ui;
 }
+
+void AtlOptionalModDialog::useShareCode() {
+    bool ok;
+    auto shareCode = QInputDialog::getText(
+            this,
+            tr("Select a share code"),
+            tr("Share code:"),
+            QLineEdit::Normal,
+            "",
+            &ok
+            );
+
+    if (!ok) {
+        // If the user cancels the dialog, we don't need to show any error dialogs.
+        return;
+    }
+
+    if (shareCode.isEmpty()) {
+        QMessageBox box;
+        box.setIcon(QMessageBox::Warning);
+        box.setText(tr("No share code specified!"));
+        box.exec();
+        return;
+    }
+
+    listModel->useShareCode(shareCode);
+}
diff --git a/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.h b/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.h
index 9832014cd..953b288ea 100644
--- a/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.h
+++ b/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.h
@@ -1,17 +1,36 @@
+// SPDX-License-Identifier: GPL-3.0-only
 /*
- * Copyright 2021 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2021 Jamie Mansfield <jmansfield@cadixdev.org>
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -20,6 +39,7 @@
 #include <QAbstractListModel>
 
 #include "modplatform/atlauncher/ATLPackIndex.h"
+#include "net/NetJob.h"
 
 namespace Ui {
 class AtlOptionalModDialog;
@@ -49,7 +69,12 @@ public:
 
     Qt::ItemFlags flags(const QModelIndex &index) const override;
 
+    void useShareCode(const QString& code);
+
 public slots:
+    void shareCodeSuccess();
+    void shareCodeFailure(const QString& reason);
+
     void selectRecommended();
     void clearAll();
 
@@ -58,6 +83,9 @@ private:
     void setMod(ATLauncher::VersionMod mod, int index, bool enable, bool shouldEmit = true);
 
 private:
+    NetJob::Ptr m_jobPtr;
+    QByteArray m_response;
+
     QVector<ATLauncher::VersionMod> m_mods;
     QMap<QString, bool> m_selection;
     QMap<QString, int> m_index;
@@ -75,6 +103,8 @@ public:
         return listModel->getResult();
     }
 
+    void useShareCode();
+
 private:
     Ui::AtlOptionalModDialog *ui;
 
diff --git a/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.ui b/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.ui
index 4c5c2ec5e..d9496142a 100644
--- a/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.ui
+++ b/launcher/ui/pages/modplatform/atlauncher/AtlOptionalModDialog.ui
@@ -24,6 +24,16 @@
      </property>
     </widget>
    </item>
+   <item row="1" column="0">
+    <widget class="QPushButton" name="shareCodeButton">
+     <property name="enabled">
+      <bool>true</bool>
+     </property>
+     <property name="text">
+      <string>Use Share Code</string>
+     </property>
+    </widget>
+   </item>
    <item row="1" column="1">
     <widget class="QPushButton" name="selectRecommendedButton">
      <property name="text">
@@ -31,16 +41,6 @@
      </property>
     </widget>
    </item>
-   <item row="1" column="0">
-    <widget class="QPushButton" name="shareCodeButton">
-     <property name="enabled">
-      <bool>false</bool>
-     </property>
-     <property name="text">
-      <string>Use Share Code</string>
-     </property>
-    </widget>
-   </item>
    <item row="1" column="2">
     <widget class="QPushButton" name="clearAllButton">
      <property name="text">