diff --git a/.clang-tidy b/.clang-tidy
index 2445ece..4757d19 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -1 +1 @@
-Checks: '*,clang-analyzer-*,-llvmlibc-*,-fuchsia-*,-altera-*,-abseil-*,-android-*,-modernize-use-trailing-return-type,-readability-identifier-length,-*-readability-todo,-*-magic-numbers,-readability-function-cognitive-complexity,-*-easily-swappable-parameters,-*-pro-type-reinterpret-cast,-*-owning-memory'
\ No newline at end of file
+Checks: '*,clang-analyzer-*,-llvmlibc-*,-fuchsia-*,-altera-*,-abseil-*,-android-*,-modernize-use-trailing-return-type,-readability-identifier-length,-*-readability-todo,-*-magic-numbers,-readability-function-cognitive-complexity,-*-easily-swappable-parameters,-*-pro-type-reinterpret-cast,-*-owning-memory,-concurrency-mt-unsafe,-cert-env33-c'
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7c72278..f81e25d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,7 +12,7 @@ set(CMAKE_AUTOUIC ON)
 
 qt6_wrap_ui(UI_HEADERS src/mainwindow.ui)
 
-add_executable(${PROJECT_NAME} src/main.cc src/mainwindow.cc ${UI_HEADERS})
+add_executable(${PROJECT_NAME} src/main.cc src/mainwindow.cc src/vault.cc ${UI_HEADERS})
 
 target_include_directories(${PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
 
diff --git a/src/common.h b/src/common.h
index 63be8e9..f448e9d 100644
--- a/src/common.h
+++ b/src/common.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <cstdint>
+#include <string>
 
 #define ASSERT(cond)                                                           \
   if (!(cond)) {                                                               \
@@ -19,4 +20,9 @@ using u64 = uint64_t;
 static_assert(sizeof(float) * 8 == 32);
 using f32 = float;
 static_assert(sizeof(double) * 8 == 64);
-using f64 = double;
\ No newline at end of file
+using f64 = double;
+
+inline std::string path_to_filename(const std::string &path) {
+  u64 pos = path.find_last_of("/\\");
+  return (pos == std::string::npos) ? path : path.substr(pos + 1);
+}
\ No newline at end of file
diff --git a/src/mainwindow.cc b/src/mainwindow.cc
index aa99172..d4da126 100644
--- a/src/mainwindow.cc
+++ b/src/mainwindow.cc
@@ -1,9 +1,8 @@
 #include "mainwindow.h"
-#include "vault.h"
-#include <QDebug>
 #include <QFileDialog>
-#include <QTreeWidgetItem>
-#include <fstream>
+#include <QInputDialog>
+#include <QTemporaryFile>
+#include <iostream>
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent), ui(new Ui::MainWindow) {
@@ -17,16 +16,8 @@ MainWindow::MainWindow(QWidget *parent)
       return;
     }
 
-    {
-      std::ofstream file(path.toStdString(), std::ios::binary);
-      Vault::write_header(file);
-
-      Vault::write_file(file, "hello.txt", "Hello, World!");
-      Vault::write_file(file, "test.txt", "test test test");
-    }
-
-    m_vault_path = path.toStdString();
-    reload_vault();
+    m_vault = Vault(path.toStdString());
+    reload_fs_tree();
   });
 
   connect(ui->actionOpen, &QAction::triggered, this, [this]() {
@@ -37,52 +28,105 @@ MainWindow::MainWindow(QWidget *parent)
       return;
     }
 
-    m_vault_path = path.toStdString();
-    reload_vault();
+    m_vault = Vault(path.toStdString());
+    reload_fs_tree();
   });
 
   connect(ui->fsTreeWidget, &QTreeWidget::itemClicked,
           [this](QTreeWidgetItem *item, int column) {
             preview_file(item->text(column).toStdString());
           });
+
+  connect(ui->fsTreeWidget, &QTreeWidget::customContextMenuRequested, this,
+          &MainWindow::file_context_menu);
+
+  connect(ui->actionAddFile, &QAction::triggered, this, [this]() {
+    if (!m_vault) {
+      return;
+    }
+
+    QString path = QFileDialog::getOpenFileName(this, "Choose a file to add");
+    if (path.isEmpty()) {
+      return;
+    }
+
+    std::ifstream file(path.toStdString(), std::ios::binary);
+
+    std::string content((std::istreambuf_iterator<char>(file)),
+                        std::istreambuf_iterator<char>());
+
+    m_vault->write_file(path_to_filename(path.toStdString()), content);
+
+    reload_fs_tree();
+  });
+
+  connect(ui->actionCreateFile, &QAction::triggered, this, [this]() {
+    if (!m_vault) {
+      return;
+    }
+
+    QString path =
+        QInputDialog::getText(this, "Create File", "Where to create the file");
+    if (path.isEmpty()) {
+      return;
+    }
+
+    m_vault->write_file(path.toStdString(), "");
+
+    reload_fs_tree();
+  });
 }
 
-void MainWindow::reload_vault() {
+void MainWindow::reload_fs_tree() {
   ui->fsTreeWidget->clear();
 
-  std::ifstream file(m_vault_path, std::ios::binary);
-  Vault::verify_header(file);
-
-  while (true) {
-    auto header = Vault::read_file_header(file);
-    if (!header) {
-      break;
-    }
-    file.seekg(static_cast<i64>(header->size), std::ios::cur);
-
+  auto headers = m_vault->read_file_headers();
+  for (const auto &header : headers) {
     auto *item = new QTreeWidgetItem(ui->fsTreeWidget);
-    item->setText(0, QString::fromStdString(header->name));
+    item->setText(0, QString::fromStdString(header.name));
   }
 }
 
 void MainWindow::preview_file(const std::string &filename) {
-  std::ifstream file(m_vault_path, std::ios::binary);
-  Vault::verify_header(file);
+  auto content = m_vault->read_file(filename);
+  if (content) {
+    ui->filePreview->setText(QString::fromStdString(content.value()));
+  } else {
+    qWarning() << "File to preview not found";
+  }
+}
 
-  while (true) {
-    auto header = Vault::read_file_header(file);
-    if (!header) {
-      break;
+void MainWindow::edit_file(const std::string &filename) {
+  auto content = m_vault->read_file(filename);
+  if (content) {
+    QTemporaryFile temp_file;
+    ASSERT(temp_file.open());
+    {
+      QTextStream out(&temp_file);
+      out << QString::fromStdString(content.value());
     }
+    temp_file.flush();
 
-    if (header->name == filename) {
-      std::string content(header->size, '\0');
-      file.read(content.data(), static_cast<i64>(header->size));
-      ui->filePreview->setText(QString::fromStdString(content));
-      return;
-    }
-    file.seekg(static_cast<i64>(header->size), std::ios::cur);
+    // TODO: xdg-open or something
+    std::system(("kwrite " + temp_file.fileName()).toStdString().c_str());
+    // TODO: write back
+  } else {
+    qWarning() << "File to edit not found";
+  }
+}
+
+void MainWindow::file_context_menu(const QPoint &pos) {
+  QTreeWidgetItem *item = ui->fsTreeWidget->itemAt(pos);
+  if (item == nullptr) {
+    return;
   }
 
-  ASSERT(false);
+  QMenu menu(this);
+
+  QAction *edit_action = menu.addAction(
+      style()->standardIcon(QStyle::SP_FileDialogDetailedView), "Edit");
+  connect(edit_action, &QAction::triggered, this,
+          [this, item]() { edit_file(item->text(0).toStdString()); });
+
+  menu.exec(ui->fsTreeWidget->mapToGlobal(pos));
 }
diff --git a/src/mainwindow.h b/src/mainwindow.h
index 3686516..f058d29 100644
--- a/src/mainwindow.h
+++ b/src/mainwindow.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "ui_mainwindow.h"
+#include "vault.h"
 #include <QMainWindow>
 
 class MainWindow : public QMainWindow {
@@ -12,8 +13,10 @@ public:
 private:
   Ui::MainWindow *ui;
 
-  std::string m_vault_path;
+  std::optional<Vault> m_vault;
 
-  void reload_vault();
+  void reload_fs_tree();
   void preview_file(const std::string &filename);
+  void edit_file(const std::string &filename);
+  void file_context_menu(const QPoint &pos);
 };
diff --git a/src/mainwindow.ui b/src/mainwindow.ui
index 4501feb..3a4a89a 100644
--- a/src/mainwindow.ui
+++ b/src/mainwindow.ui
@@ -11,12 +11,15 @@
    </rect>
   </property>
   <property name="windowTitle">
-   <string>MainWindow</string>
+   <string>dull</string>
   </property>
   <widget class="QWidget" name="centralwidget">
    <layout class="QHBoxLayout" name="horizontalLayout">
     <item>
      <widget class="QTreeWidget" name="fsTreeWidget">
+      <property name="contextMenuPolicy">
+       <enum>Qt::ContextMenuPolicy::CustomContextMenu</enum>
+      </property>
       <column>
        <property name="text">
         <string>Name</string>
@@ -25,8 +28,7 @@
      </widget>
     </item>
     <item>
-     <widget class="QTextBrowser" name="filePreview">
-     </widget>
+     <widget class="QTextBrowser" name="filePreview"/>
     </item>
    </layout>
   </widget>
@@ -46,7 +48,15 @@
     <addaction name="actionNew"/>
     <addaction name="actionOpen"/>
    </widget>
+   <widget class="QMenu" name="menuFiles">
+    <property name="title">
+     <string>Files</string>
+    </property>
+    <addaction name="actionCreateFile"/>
+    <addaction name="actionAddFile"/>
+   </widget>
    <addaction name="menuFile"/>
+   <addaction name="menuFiles"/>
   </widget>
   <action name="actionNew">
    <property name="text">
@@ -58,6 +68,16 @@
     <string>Open</string>
    </property>
   </action>
+  <action name="actionAddFile">
+   <property name="text">
+    <string>Add</string>
+   </property>
+  </action>
+  <action name="actionCreateFile">
+   <property name="text">
+    <string>Create</string>
+   </property>
+  </action>
  </widget>
  <resources/>
  <connections/>
diff --git a/src/vault.cc b/src/vault.cc
new file mode 100644
index 0000000..6248084
--- /dev/null
+++ b/src/vault.cc
@@ -0,0 +1,92 @@
+#include "vault.h"
+#include "common.h"
+#include <array>
+#include <iostream>
+
+Vault::Vault(std::string path) : m_path(std::move(path)) {
+  m_file.open(m_path, std::ios::in | std::ios::out | std::ios::binary);
+  if (!m_file.is_open()) {
+    std::ofstream create(m_path, std::ios::binary);
+    create.write("DULL", 4);
+    create.write(reinterpret_cast<const char *>(&VERSION), sizeof(VERSION));
+    create.close();
+    m_file.open(m_path, std::ios::in | std::ios::out | std::ios::binary);
+  }
+
+  ASSERT(m_file.good());
+
+  std::array<char, 4> header{};
+  ASSERT(static_cast<bool>(m_file.read(header.data(), header.size())));
+  ASSERT(std::string_view(header.data(), header.size()) == "DULL");
+
+  std::int16_t version = 0;
+  ASSERT(m_file.read(reinterpret_cast<char *>(&version), sizeof(version)));
+  ASSERT(version == VERSION);
+}
+
+std::vector<FileHeader> Vault::read_file_headers() {
+  std::vector<FileHeader> headers;
+
+  m_file.clear();
+  m_file.seekg(AFTER_HEADER_OFFSET, std::ios::beg);
+
+  while (true) {
+    u64 name_size = 0;
+    if (!m_file.read(reinterpret_cast<char *>(&name_size), sizeof(u64))) {
+      break;
+    }
+
+    FileHeader header{};
+    header.name.resize(name_size);
+    m_file.read(header.name.data(), static_cast<i64>(name_size));
+
+    m_file.read(reinterpret_cast<char *>(&header.size), sizeof(u64));
+    m_file.seekg(static_cast<i64>(header.size), std::ios::cur);
+
+    headers.push_back(header);
+  }
+
+  return headers;
+}
+
+std::optional<std::string> Vault::read_file(const std::string &filename) {
+  m_file.clear();
+  m_file.seekg(AFTER_HEADER_OFFSET, std::ios::beg);
+
+  while (true) {
+    u64 name_size = 0;
+    if (!m_file.read(reinterpret_cast<char *>(&name_size), sizeof(u64))) {
+      break;
+    }
+
+    std::string name;
+    name.resize(name_size);
+    m_file.read(name.data(), static_cast<i64>(name_size));
+
+    u64 content_size = 0;
+    m_file.read(reinterpret_cast<char *>(&content_size), sizeof(u64));
+
+    if (name == filename) {
+      std::string content(content_size, '\0');
+      m_file.read(content.data(), static_cast<i64>(content_size));
+      return content;
+    }
+
+    m_file.seekg(static_cast<i64>(content_size), std::ios::cur);
+  }
+
+  return std::nullopt;
+}
+
+void Vault::write_file(const std::string &name, const std::string &content) {
+  m_file.clear();
+  m_file.seekp(0, std::ios::end);
+
+  u64 name_size = name.size();
+  u64 content_size = content.size();
+  m_file.write(reinterpret_cast<const char *>(&name_size), sizeof(u64));
+  m_file.write(name.data(), static_cast<i64>(name_size));
+  m_file.write(reinterpret_cast<const char *>(&content_size), sizeof(u64));
+  m_file.write(content.data(), static_cast<i64>(content_size));
+  m_file.flush();
+}
diff --git a/src/vault.h b/src/vault.h
index 4cd1ee5..4351f5c 100644
--- a/src/vault.h
+++ b/src/vault.h
@@ -1,52 +1,27 @@
 #pragma once
 
 #include "common.h"
-#include <array>
 #include <fstream>
-#include <iostream>
 #include <optional>
+#include <vector>
 
-namespace Vault {
-
-inline void verify_header(std::ifstream &file) {
-  ASSERT(file.good());
-
-  std::array<char, 4> header{};
-  ASSERT(file.read(header.data(), header.size()));
-  ASSERT(std::string_view(header.data(), header.size()) == "DULL");
-}
+constexpr i16 VERSION = 1;
+constexpr u64 AFTER_HEADER_OFFSET = 6;
 
 struct FileHeader {
   std::string name;
   u64 size;
 };
 
-inline std::optional<FileHeader> read_file_header(std::ifstream &file) {
-  FileHeader header{};
+class Vault {
+public:
+  explicit Vault(std::string path);
 
-  u64 name_size = 0;
-  if (!file.read(reinterpret_cast<char *>(&name_size), sizeof(u64))) {
-    return std::nullopt;
-  }
+  std::vector<FileHeader> read_file_headers();
+  std::optional<std::string> read_file(const std::string &name);
+  void write_file(const std::string &name, const std::string &content);
 
-  header.name = std::string(name_size, '\0');
-  file.read(header.name.data(), static_cast<i64>(name_size));
-
-  file.read(reinterpret_cast<char *>(&header.size), sizeof(u64));
-
-  return header;
-}
-
-inline void write_header(std::ofstream &file) { file.write("DULL", 4); }
-
-inline void write_file(std::ofstream &file, const std::string &name,
-                       const std::string &content) {
-  u64 name_size = name.size();
-  u64 content_size = content.size();
-  file.write(reinterpret_cast<const char *>(&name_size), sizeof(u64));
-  file.write(name.data(), static_cast<i64>(name_size));
-  file.write(reinterpret_cast<const char *>(&content_size), sizeof(u64));
-  file.write(content.data(), static_cast<i64>(content_size));
-}
-
-}; // namespace Vault
\ No newline at end of file
+private:
+  std::string m_path;
+  std::fstream m_file;
+};