diff --git a/CMakeLists.txt b/CMakeLists.txt
index fe45f23..26ebac5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,9 +17,12 @@ include_directories(${PROJECT_SOURCE_DIR}/src)
 
 # Source files - we will add them later
 set(SRC_FILES
+    src/main.cpp
     src/core/translator.cpp
-    src/services/synchronizer.cpp
-    # placeholder
+    src/core/mailitem.cpp
+    src/core/models/account.cpp
+    src/core/models/folder.cpp
+    # src/services/synchronizer.cpp  # placeholder
 )
 
 # Executable
diff --git a/src/core/mailitem.cpp b/src/core/mailitem.cpp
new file mode 100644
index 0000000..08ac80a
--- /dev/null
+++ b/src/core/mailitem.cpp
@@ -0,0 +1,16 @@
+#include "mailitem.h"
+
+MailItem::MailItem(qint64 id, const QString& subject, const QString& sender,
+                   const QString& recipient, const QDateTime& date,
+                   bool read, bool flagged,
+                   const QVector<QString>& attachments)
+    : m_id(id)
+    , m_subject(subject)
+    , m_sender(sender)
+    , m_recipient(recipient)
+    , m_date(date)
+    , m_read(read)
+    , m_flagged(flagged)
+    , m_attachments(attachments)
+{
+}
\ No newline at end of file
diff --git a/src/core/models/account.cpp b/src/core/models/account.cpp
new file mode 100644
index 0000000..5841fa0
--- /dev/null
+++ b/src/core/models/account.cpp
@@ -0,0 +1,14 @@
+#include "account.h"
+
+Account::Account(int id, const QString& email, const QString& displayName,
+                 AccountType type, const QString& accessToken,
+                 const QString& refreshToken, const QDateTime& tokenExpires)
+    : m_id(id)
+    , m_email(email)
+    , m_displayName(displayName)
+    , m_type(type)
+    , m_accessToken(accessToken)
+    , m_refreshToken(refreshToken)
+    , m_tokenExpires(tokenExpires)
+{
+}
\ No newline at end of file
diff --git a/src/core/models/account.h b/src/core/models/account.h
new file mode 100644
index 0000000..5ad6548
--- /dev/null
+++ b/src/core/models/account.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <QString>
+#include <QDateTime>
+
+enum class AccountType {
+    Outlook,
+    Gmail,
+    IMAP
+};
+
+class Account
+{
+public:
+    Account() = default;
+    Account(int id, const QString& email, const QString& displayName,
+            AccountType type, const QString& accessToken = QString(),
+            const QString& refreshToken = QString(),
+            const QDateTime& tokenExpires = QDateTime());
+
+    int id() const { return m_id; }
+    void setId(int id) { m_id = id; }
+
+    QString email() const { return m_email; }
+    void setEmail(const QString& email) { m_email = email; }
+
+    QString displayName() const { return m_displayName; }
+    void setDisplayName(const QString& displayName) { m_displayName = displayName; }
+
+    AccountType type() const { return m_type; }
+    void setType(AccountType type) { m_type = type; }
+
+    QString accessToken() const { return m_accessToken; }
+    void setAccessToken(const QString& token) { m_accessToken = token; }
+
+    QString refreshToken() const { return m_refreshToken; }
+    void setRefreshToken(const QString& token) { m_refreshToken = token; }
+
+    QDateTime tokenExpires() const { return m_tokenExpires; }
+    void setTokenExpires(const QDateTime& expires) { m_tokenExpires = expires; }
+
+    bool isTokenValid() const {
+        return !m_accessToken.isEmpty() && m_tokenExpires.isValid() &&
+               m_tokenExpires > QDateTime::currentDateTimeUtc();
+    }
+
+private:
+    int m_id{0};
+    QString m_email;
+    QString m_displayName;
+    AccountType m_type{AccountType::IMAP};
+    QString m_accessToken;
+    QString m_refreshToken;
+    QDateTime m_tokenExpires;
+};
\ No newline at end of file
diff --git a/src/core/models/folder.cpp b/src/core/models/folder.cpp
new file mode 100644
index 0000000..67ba392
--- /dev/null
+++ b/src/core/models/folder.cpp
@@ -0,0 +1,17 @@
+#include "folder.h"
+
+Folder::Folder(int id, int accountId, const QString& name, const QString& parentFolderId,
+               bool isInbox, bool isSent, bool isDrafts, bool isTrash,
+               int unreadCount, const QDateTime& lastSynced)
+    : m_id(id)
+    , m_accountId(accountId)
+    , m_name(name)
+    , m_parentFolderId(parentFolderId)
+    , m_isInbox(isInbox)
+    , m_isSent(isSent)
+    , m_isDrafts(isDrafts)
+    , m_isTrash(isTrash)
+    , m_unreadCount(unreadCount)
+    , m_lastSynced(lastSynced)
+{
+}
\ No newline at end of file
diff --git a/src/core/models/folder.h b/src/core/models/folder.h
new file mode 100644
index 0000000..9bf622d
--- /dev/null
+++ b/src/core/models/folder.h
@@ -0,0 +1,55 @@
+#pragma once
+
+#include <QString>
+#include <QDateTime>
+
+class Folder
+{
+public:
+    Folder() = default;
+    Folder(int id, int accountId, const QString& name, const QString& parentFolderId = QString(),
+           bool isInbox = false, bool isSent = false, bool isDrafts = false, bool isTrash = false,
+           int unreadCount = 0, const QDateTime& lastSynced = QDateTime());
+
+    int id() const { return m_id; }
+    void setId(int id) { m_id = id; }
+
+    int accountId() const { return m_accountId; }
+    void setAccountId(int accountId) { m_accountId = accountId; }
+
+    QString name() const { return m_name; }
+    void setName(const QString& name) { m_name = name; }
+
+    QString parentFolderId() const { return m_parentFolderId; }
+    void setParentFolderId(const QString& parentFolderId) { m_parentFolderId = parentFolderId; }
+
+    bool isInbox() const { return m_isInbox; }
+    void setInbox(bool inbox) { m_isInbox = inbox; }
+
+    bool isSent() const { return m_isSent; }
+    void setSent(bool sent) { m_isSent = sent; }
+
+    bool isDrafts() const { return m_isDrafts; }
+    void setDrafts(bool drafts) { m_isDrafts = drafts; }
+
+    bool isTrash() const { return m_isTrash; }
+    void setTrash(bool trash) { m_isTrash = trash; }
+
+    int unreadCount() const { return m_unreadCount; }
+    void setUnreadCount(int count) { m_unreadCount = count; }
+
+    QDateTime lastSynced() const { return m_lastSynced; }
+    void setLastSynced(const QDateTime& lastSynced) { m_lastSynced = lastSynced; }
+
+private:
+    int m_id{0};
+    int m_accountId{0};
+    QString m_name;
+    QString m_parentFolderId;
+    bool m_isInbox{false};
+    bool m_isSent{false};
+    bool m_isDrafts{false};
+    bool m_isTrash{false};
+    int m_unreadCount{0};
+    QDateTime m_lastSynced;
+};
\ No newline at end of file