diff --git a/cpp17/.clang-format b/cpp17/.clang-format
new file mode 100644
index 0000000..1fce9b2
--- /dev/null
+++ b/cpp17/.clang-format
@@ -0,0 +1,83 @@
+---
+Language: Cpp
+AccessModifierOffset: -2
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlines: Right
+AlignOperands: true
+AlignTrailingComments: true
+AllowAllArgumentsOnNextLine: true
+AllowAllConstructorInitializersOnNextLine: true
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: false
+AlwaysBreakTemplateDeclarations: MultiLine
+BinPackArguments: true
+BinPackParameters: true
+BreakBeforeBinaryOperators: NonAssignment
+BreakBeforeBraces: Custom
+BraceWrapping:
+  AfterClass: true
+  AfterControlStatement: false
+  AfterEnum: false
+  AfterFunction: true
+  AfterNamespace: false
+  AfterStruct: true
+  AfterUnion: false
+  AfterExternBlock: false
+  BeforeCatch: false
+  BeforeElse: false
+  IndentBraces: false
+  SplitEmptyFunction: false
+  SplitEmptyRecord: false
+  SplitEmptyNamespace: false
+BreakBeforeInheritanceComma: false
+BreakInheritanceList: BeforeColon
+ColumnLimit: 80
+CompactNamespaces: false
+ConstructorInitializerIndentWidth: 2
+ContinuationIndentWidth: 2
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat: false
+ExperimentalAutoDetectBinPacking: false
+FixNamespaceComments: true
+IndentCaseLabels: true
+IndentPPDirectives: None
+IndentWidth: 2
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+# LambdaBodyIndentation: Signature
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+PointerAlignment: Left
+ReflowComments: true
+SortIncludes: false
+SortUsingDeclarations: false
+SpaceAfterCStyleCast: false
+SpaceAfterLogicalNot: false
+SpaceAfterTemplateKeyword: true
+# SpaceAroundPointerQualifiers: Default
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeCpp11BracedList: false
+SpaceBeforeCtorInitializerColon: true
+SpaceBeforeInheritanceColon: true
+SpaceBeforeParens: ControlStatements
+SpaceBeforeRangeBasedForLoopColon: true
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 1
+SpacesInAngles: false
+SpacesInCStyleCastParentheses: false
+SpacesInConditionalStatement: false
+SpacesInContainerLiterals: true
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+TabWidth: 8
+UseTab: Never
diff --git a/cpp17/app/src/App.cpp b/cpp17/app/src/App.cpp
index 333c014..289b258 100644
--- a/cpp17/app/src/App.cpp
+++ b/cpp17/app/src/App.cpp
@@ -1,25 +1,37 @@
 #include "App.h"
-#include "autostore/AutoStore.h"
 #include <iostream>
 
-namespace nxl
+namespace nxl {
+
+std::condition_variable App::exitCv;
+std::mutex App::mtx;
+bool App::shouldExit = false;
+
+App::App(int argc, char** argv)
 {
-    App::App(int argc, char **argv)
-    {
-        signal(SIGINT, App::handle_signal);
-        signal(SIGTERM, App::handle_signal);
-    }
-
-    int App::exec()
-    {
-        nxl::AutoStore autostore;
-        autostore.run();
-        return 0;
-    }
-
-    void App::handle_signal(int signum)
-    {
-        std::cout << "\nCaught signal " << signum << ". Graceful shutdown." << std::endl;
-        exit(signum);
-    }
-}
\ No newline at end of file
+  signal(SIGINT, App::handleSignal);
+  signal(SIGTERM, App::handleSignal);
+}
+
+int App::exec()
+{
+  // TODO: start application services when implemented
+
+  std::unique_lock<std::mutex> lock(mtx);
+  exitCv.wait(lock, [] { return shouldExit; });
+
+  return 0;
+}
+
+void App::handleSignal(int signum)
+{
+  std::cout << "\nCaught signal " << signum << ". Graceful shutdown."
+            << std::endl;
+  {
+    std::lock_guard<std::mutex> lock(mtx);
+    shouldExit = true;
+  }
+  exitCv.notify_one();
+}
+
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/app/src/App.h b/cpp17/app/src/App.h
index 39b048b..29fab1d 100644
--- a/cpp17/app/src/App.h
+++ b/cpp17/app/src/App.h
@@ -1,16 +1,24 @@
 #pragma once
 
+#include <atomic>
+#include <condition_variable>
 #include <csignal>
+#include <mutex>
+#include <thread>
 
-namespace nxl
+namespace nxl {
+
+class App
 {
-    class App
-    {
-    public:
-        App(int argc, char **argv);
-        int exec();
+public:
+  App(int argc, char** argv);
+  int exec();
+
+private:
+  static void handleSignal(int signum);
+  static std::condition_variable exitCv;
+  static std::mutex mtx;
+  static bool shouldExit;
+};
 
-    private:
-        static void handle_signal(int signum);
-    };
-}
\ No newline at end of file
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/app/src/Main.cpp b/cpp17/app/src/Main.cpp
index 07d46d7..a9baa97 100644
--- a/cpp17/app/src/Main.cpp
+++ b/cpp17/app/src/Main.cpp
@@ -2,9 +2,9 @@
 #include "Version.h"
 #include <iostream>
 
-int main(int argc, char **argv)
+int main(int argc, char** argv)
 {
-    std::cout << "AutoStore v" << nxl::getVersionString() << std::endl;
-    nxl::App app(argc, argv);
-    return app.exec();
+  std::cout << "AutoStore v" << nxl::getVersionString() << std::endl;
+  nxl::App app(argc, argv);
+  return app.exec();
 }
diff --git a/cpp17/app/src/Version.h.in b/cpp17/app/src/Version.h.in
index 4eb6c96..b92fe98 100644
--- a/cpp17/app/src/Version.h.in
+++ b/cpp17/app/src/Version.h.in
@@ -3,17 +3,18 @@
 
 #include <string>
 
-namespace nxl
-{
-  static constexpr int VERSION_MAJOR = ${PROJECT_VERSION_MAJOR};
-  static constexpr int VERSION_MINOR = ${PROJECT_VERSION_MINOR};
-  static constexpr int VERSION_PATCH = ${PROJECT_VERSION_PATCH};
-  static constexpr char VERSION_SUFFIX[] = "${PROJECT_VERSION_SUFFIX}";
+namespace nxl {
+
+static constexpr int VERSION_MAJOR = ${PROJECT_VERSION_MAJOR};
+static constexpr int VERSION_MINOR = ${PROJECT_VERSION_MINOR};
+static constexpr int VERSION_PATCH = ${PROJECT_VERSION_PATCH};
+static constexpr char VERSION_SUFFIX[] = "${PROJECT_VERSION_SUFFIX}";
 
-  inline std::string getVersionString()
-  {
-    return std::to_string(VERSION_MAJOR) + "." + std::to_string(VERSION_MINOR) + "." + std::to_string(VERSION_PATCH) + VERSION_SUFFIX;
-  }
+inline std::string getVersionString()
+{
+  return std::to_string(VERSION_MAJOR) + "." + std::to_string(VERSION_MINOR)
+         + "." + std::to_string(VERSION_PATCH) + VERSION_SUFFIX;
+}
 
 } // namespace nxl
 
diff --git a/cpp17/lib/CMakeLists.txt b/cpp17/lib/CMakeLists.txt
index f687ee9..0a9b243 100644
--- a/cpp17/lib/CMakeLists.txt
+++ b/cpp17/lib/CMakeLists.txt
@@ -7,20 +7,35 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 
 add_library(${TARGET_NAME} STATIC
-    src/AutoStore.cpp
+    src/infrastructure/repositories/FileUserRepository.cpp
+    src/infrastructure/repositories/FileItemRepository.cpp
 )
 
 target_include_directories(${TARGET_NAME}
     PUBLIC
-        ${CMAKE_CURRENT_SOURCE_DIR}/include
+        ${CMAKE_CURRENT_SOURCE_DIR}/include/autostore
+)
+
+target_sources(${TARGET_NAME}
+    PUBLIC
+        FILE_SET HEADERS
+        BASE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/include
+        FILES
+            include/autostore/domain/entities/User.h
+            include/autostore/domain/entities/Item.h
+            include/autostore/application/interfaces/IUserRepository.h
+            include/autostore/application/interfaces/IItemRepository.h
+            include/autostore/application/interfaces/IAuthService.h
 )
 
 # Find dependencies
 find_package(httplib CONFIG REQUIRED)
 find_package(Catch2 CONFIG REQUIRED)
+find_package(nlohmann_json CONFIG REQUIRED)
 
 target_link_libraries(${TARGET_NAME}
     PUBLIC
         httplib::httplib
         Catch2::Catch2WithMain
+        nlohmann_json::nlohmann_json
 )
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/AutoStore.h b/cpp17/lib/include/autostore/AutoStore.h
deleted file mode 100644
index 0338ad9..0000000
--- a/cpp17/lib/include/autostore/AutoStore.h
+++ /dev/null
@@ -1,11 +0,0 @@
-#pragma once
-
-namespace nxl
-{
-    class AutoStore
-    {
-    public:
-        AutoStore();
-        void run();
-    };
-} // namespace nxl
diff --git a/cpp17/lib/include/autostore/application/interfaces/IAuthService.h b/cpp17/lib/include/autostore/application/interfaces/IAuthService.h
new file mode 100644
index 0000000..cd74605
--- /dev/null
+++ b/cpp17/lib/include/autostore/application/interfaces/IAuthService.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <string>
+#include <string_view>
+#include <optional>
+
+namespace nxl {
+namespace autostore {
+namespace application {
+
+class IAuthService
+{
+public:
+  virtual ~IAuthService() = default;
+  virtual std::string generateToken(std::string_view userId) = 0;
+  virtual std::optional<std::string> validateToken(std::string_view token) = 0;
+};
+
+} // namespace application
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/application/interfaces/IItemRepository.h b/cpp17/lib/include/autostore/application/interfaces/IItemRepository.h
new file mode 100644
index 0000000..a0d0efd
--- /dev/null
+++ b/cpp17/lib/include/autostore/application/interfaces/IItemRepository.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include "domain/entities/Item.h"
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace nxl {
+namespace autostore {
+namespace application {
+
+class IItemRepository
+{
+public:
+  virtual ~IItemRepository() = default;
+  virtual void save(const domain::Item& item) = 0;
+  virtual std::optional<domain::Item> findById(std::string_view id) = 0;
+  virtual std::vector<domain::Item> findByUser(std::string_view userId) = 0;
+  virtual std::vector<domain::Item> findAll() = 0;
+  virtual void remove(std::string_view id) = 0;
+};
+
+} // namespace application
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/application/interfaces/IUserRepository.h b/cpp17/lib/include/autostore/application/interfaces/IUserRepository.h
new file mode 100644
index 0000000..59641c8
--- /dev/null
+++ b/cpp17/lib/include/autostore/application/interfaces/IUserRepository.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include "domain/entities/User.h"
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace nxl {
+namespace autostore {
+namespace application {
+
+class IUserRepository
+{
+public:
+  virtual ~IUserRepository() = default;
+  virtual void save(const domain::User& user) = 0;
+  virtual std::optional<domain::User> findById(std::string_view id) = 0;
+  virtual std::optional<domain::User>
+  findByUsername(std::string_view username) = 0;
+  virtual std::vector<domain::User> findAll() = 0;
+  virtual void remove(std::string_view id) = 0;
+};
+
+} // namespace application
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/domain/entities/Item.h b/cpp17/lib/include/autostore/domain/entities/Item.h
new file mode 100644
index 0000000..04d1e35
--- /dev/null
+++ b/cpp17/lib/include/autostore/domain/entities/Item.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#include <string>
+#include <chrono>
+
+namespace nxl {
+namespace autostore {
+namespace domain {
+
+struct Item
+{
+  std::string id;
+  std::string name;
+  std::chrono::system_clock::time_point expirationDate;
+  std::string orderUrl;
+  std::string userId;
+};
+
+} // namespace domain
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/domain/entities/User.h b/cpp17/lib/include/autostore/domain/entities/User.h
new file mode 100644
index 0000000..f28f1d2
--- /dev/null
+++ b/cpp17/lib/include/autostore/domain/entities/User.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include <string>
+
+namespace nxl {
+namespace autostore {
+namespace domain {
+
+struct User
+{
+  std::string id;
+  std::string username;
+  std::string passwordHash;
+};
+
+} // namespace domain
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/infrastructure/repositories/FileItemRepository.h b/cpp17/lib/include/autostore/infrastructure/repositories/FileItemRepository.h
new file mode 100644
index 0000000..4be0415
--- /dev/null
+++ b/cpp17/lib/include/autostore/infrastructure/repositories/FileItemRepository.h
@@ -0,0 +1,33 @@
+#pragma once
+
+#include "application/interfaces/IItemRepository.h"
+#include <string>
+#include <vector>
+#include <mutex>
+
+namespace nxl {
+namespace autostore {
+namespace infrastructure {
+
+class FileItemRepository : public application::IItemRepository
+{
+public:
+  explicit FileItemRepository(std::string_view dbPath);
+  void save(const domain::Item& item) override;
+  std::optional<domain::Item> findById(std::string_view id) override;
+  std::vector<domain::Item> findByUser(std::string_view userId) override;
+  std::vector<domain::Item> findAll() override;
+  void remove(std::string_view id) override;
+
+private:
+  void load();
+  void persist();
+
+  std::string dbPath;
+  std::vector<domain::Item> items;
+  std::mutex mtx;
+};
+
+} // namespace infrastructure
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/include/autostore/infrastructure/repositories/FileUserRepository.h b/cpp17/lib/include/autostore/infrastructure/repositories/FileUserRepository.h
new file mode 100644
index 0000000..8594ff8
--- /dev/null
+++ b/cpp17/lib/include/autostore/infrastructure/repositories/FileUserRepository.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include "application/interfaces/IUserRepository.h"
+#include <string>
+#include <vector>
+#include <mutex>
+
+namespace nxl {
+namespace autostore {
+namespace infrastructure {
+
+class FileUserRepository : public application::IUserRepository
+{
+public:
+  explicit FileUserRepository(std::string_view dbPath);
+  void save(const domain::User& user) override;
+  std::optional<domain::User> findById(std::string_view id) override;
+  std::optional<domain::User>
+  findByUsername(std::string_view username) override;
+  std::vector<domain::User> findAll() override;
+  void remove(std::string_view id) override;
+
+private:
+  void load();
+  void persist();
+
+  std::string dbPath;
+  std::vector<domain::User> users;
+  std::mutex mtx;
+};
+
+} // namespace infrastructure
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/src/AutoStore.cpp b/cpp17/lib/src/AutoStore.cpp
deleted file mode 100644
index 8e7f14b..0000000
--- a/cpp17/lib/src/AutoStore.cpp
+++ /dev/null
@@ -1,15 +0,0 @@
-#include "autostore/AutoStore.h"
-#include <iostream>
-
-namespace nxl
-{
-    AutoStore::AutoStore()
-    {
-        std::cout << "AutoStore library initialized." << std::endl;
-    }
-
-    void AutoStore::run()
-    {
-        std::cout << "AutoStore library is running." << std::endl;
-    }
-} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/src/infrastructure/repositories/FileItemRepository.cpp b/cpp17/lib/src/infrastructure/repositories/FileItemRepository.cpp
new file mode 100644
index 0000000..cde7a8f
--- /dev/null
+++ b/cpp17/lib/src/infrastructure/repositories/FileItemRepository.cpp
@@ -0,0 +1,142 @@
+#include "infrastructure/repositories/FileItemRepository.h"
+#include "nlohmann/json.hpp"
+#include <fstream>
+#include <algorithm>
+#include <chrono>
+#include <ctime>
+#include <iterator>
+
+namespace nxl {
+namespace autostore {
+namespace infrastructure {
+
+namespace {
+
+// Helper functions for JSON serialization
+inline void itemToJson(nlohmann::json& j, const domain::Item& item)
+{
+  j =
+    nlohmann::json{{"id", item.id},
+                   {"name", item.name},
+                   {"expirationDate",
+                    std::chrono::system_clock::to_time_t(item.expirationDate)},
+                   {"orderUrl", item.orderUrl},
+                   {"userId", item.userId}};
+}
+
+inline void jsonToItem(const nlohmann::json& j, domain::Item& item)
+{
+  j.at("id").get_to(item.id);
+  j.at("name").get_to(item.name);
+  std::time_t expirationTime;
+  j.at("expirationDate").get_to(expirationTime);
+  item.expirationDate = std::chrono::system_clock::from_time_t(expirationTime);
+  j.at("orderUrl").get_to(item.orderUrl);
+  j.at("userId").get_to(item.userId);
+}
+
+// Helper functions for vector serialization
+inline nlohmann::json itemsToJson(const std::vector<domain::Item>& items)
+{
+  nlohmann::json j = nlohmann::json::array();
+  for (const auto& item : items) {
+    nlohmann::json itemJson;
+    itemToJson(itemJson, item);
+    j.push_back(itemJson);
+  }
+  return j;
+}
+
+inline std::vector<domain::Item> jsonToItems(const nlohmann::json& j)
+{
+  std::vector<domain::Item> items;
+  for (const auto& itemJson : j) {
+    domain::Item item;
+    jsonToItem(itemJson, item);
+    items.push_back(item);
+  }
+  return items;
+}
+
+} // namespace
+
+FileItemRepository::FileItemRepository(std::string_view dbPath) : dbPath(dbPath)
+{
+  load();
+}
+
+void FileItemRepository::save(const domain::Item& item)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  auto it =
+    std::find_if(items.begin(), items.end(),
+                 [&](const domain::Item& i) { return i.id == item.id; });
+
+  if (it != items.end()) {
+    *it = item;
+  } else {
+    items.push_back(item);
+  }
+  persist();
+}
+
+std::optional<domain::Item> FileItemRepository::findById(std::string_view id)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  auto it = std::find_if(items.begin(), items.end(),
+                         [&](const domain::Item& i) { return i.id == id; });
+
+  if (it != items.end()) {
+    return *it;
+  }
+  return std::nullopt;
+}
+
+std::vector<domain::Item>
+FileItemRepository::findByUser(std::string_view userId)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  std::vector<domain::Item> userItems;
+  std::copy_if(items.begin(), items.end(), std::back_inserter(userItems),
+               [&](const domain::Item& i) { return i.userId == userId; });
+  return userItems;
+}
+
+std::vector<domain::Item> FileItemRepository::findAll()
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  return items;
+}
+
+void FileItemRepository::remove(std::string_view id)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  items.erase(std::remove_if(items.begin(), items.end(),
+                             [&](const domain::Item& i) { return i.id == id; }),
+              items.end());
+  persist();
+}
+
+void FileItemRepository::load()
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  std::ifstream file(dbPath);
+  if (file.is_open()) {
+    nlohmann::json j;
+    file >> j;
+    items = jsonToItems(j);
+  }
+}
+
+void FileItemRepository::persist()
+{
+  std::ofstream file(dbPath);
+  if (file.is_open()) {
+    nlohmann::json j = itemsToJson(items);
+    file << j.dump(4);
+  }
+}
+
+} // namespace infrastructure
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/lib/src/infrastructure/repositories/FileUserRepository.cpp b/cpp17/lib/src/infrastructure/repositories/FileUserRepository.cpp
new file mode 100644
index 0000000..0073699
--- /dev/null
+++ b/cpp17/lib/src/infrastructure/repositories/FileUserRepository.cpp
@@ -0,0 +1,134 @@
+#include "infrastructure/repositories/FileUserRepository.h"
+#include "nlohmann/json.hpp"
+#include <fstream>
+#include <algorithm>
+
+namespace nxl {
+namespace autostore {
+namespace infrastructure {
+
+namespace {
+
+// Helper functions for JSON serialization
+inline void userToJson(nlohmann::json& j, const domain::User& u)
+{
+  j = nlohmann::json{
+    {"id", u.id}, {"username", u.username}, {"passwordHash", u.passwordHash}};
+}
+
+inline void jsonToUser(const nlohmann::json& j, domain::User& u)
+{
+  j.at("id").get_to(u.id);
+  j.at("username").get_to(u.username);
+  j.at("passwordHash").get_to(u.passwordHash);
+}
+
+// Helper functions for vector serialization
+inline nlohmann::json usersToJson(const std::vector<domain::User>& users)
+{
+  nlohmann::json j = nlohmann::json::array();
+  for (const auto& user : users) {
+    nlohmann::json userJson;
+    userToJson(userJson, user);
+    j.push_back(userJson);
+  }
+  return j;
+}
+
+inline std::vector<domain::User> jsonToUsers(const nlohmann::json& j)
+{
+  std::vector<domain::User> users;
+  for (const auto& userJson : j) {
+    domain::User user;
+    jsonToUser(userJson, user);
+    users.push_back(user);
+  }
+  return users;
+}
+
+} // namespace
+
+FileUserRepository::FileUserRepository(std::string_view dbPath) : dbPath(dbPath)
+{
+  load();
+}
+
+void FileUserRepository::save(const domain::User& user)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  auto it =
+    std::find_if(users.begin(), users.end(),
+                 [&](const domain::User& u) { return u.id == user.id; });
+
+  if (it != users.end()) {
+    *it = user;
+  } else {
+    users.push_back(user);
+  }
+  persist();
+}
+
+std::optional<domain::User> FileUserRepository::findById(std::string_view id)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  auto it = std::find_if(users.begin(), users.end(),
+                         [&](const domain::User& u) { return u.id == id; });
+
+  if (it != users.end()) {
+    return *it;
+  }
+  return std::nullopt;
+}
+
+std::optional<domain::User>
+FileUserRepository::findByUsername(std::string_view username)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  auto it =
+    std::find_if(users.begin(), users.end(),
+                 [&](const domain::User& u) { return u.username == username; });
+
+  if (it != users.end()) {
+    return *it;
+  }
+  return std::nullopt;
+}
+
+std::vector<domain::User> FileUserRepository::findAll()
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  return users;
+}
+
+void FileUserRepository::remove(std::string_view id)
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  users.erase(std::remove_if(users.begin(), users.end(),
+                             [&](const domain::User& u) { return u.id == id; }),
+              users.end());
+  persist();
+}
+
+void FileUserRepository::load()
+{
+  std::lock_guard<std::mutex> lock(mtx);
+  std::ifstream file(dbPath);
+  if (file.is_open()) {
+    nlohmann::json j;
+    file >> j;
+    users = jsonToUsers(j);
+  }
+}
+
+void FileUserRepository::persist()
+{
+  std::ofstream file(dbPath);
+  if (file.is_open()) {
+    nlohmann::json j = usersToJson(users);
+    file << j.dump(4);
+  }
+}
+
+} // namespace infrastructure
+} // namespace autostore
+} // namespace nxl
\ No newline at end of file
diff --git a/cpp17/vcpkg.json b/cpp17/vcpkg.json
index 4b8aba5..cecd049 100644
--- a/cpp17/vcpkg.json
+++ b/cpp17/vcpkg.json
@@ -3,6 +3,7 @@
   "version-string": "1.0.0",
   "dependencies": [
     "cpp-httplib",
-    "catch2"
+    "catch2",
+    "nlohmann-json"
   ]
 }