diff --git a/src-tauri/src/launcher/auth.rs b/src-tauri/src/launcher/auth.rs
new file mode 100644
index 0000000..45cd859
--- /dev/null
+++ b/src-tauri/src/launcher/auth.rs
@@ -0,0 +1,135 @@
+use std::{fs, path::PathBuf};
+
+use reqwest::Client;
+use tauri::command;
+
+use lyceris::auth::microsoft::{authenticate, create_link, refresh, validate, MinecraftAccount};
+
+use crate::launcher::LAUNCHER_DIR;
+
+fn accounts_path() -> PathBuf {
+    LAUNCHER_DIR.data_dir().join("accounts.json")
+}
+
+fn load_accounts() -> Vec<MinecraftAccount> {
+    let path = accounts_path();
+
+    if !path.exists() {
+        return vec![];
+    }
+
+    let data = fs::read_to_string(path).unwrap_or_default();
+    serde_json::from_str(&data).unwrap_or_default()
+}
+
+fn save_accounts(accounts: &[MinecraftAccount]) -> Result<(), String> {
+    let path = accounts_path();
+
+    if let Some(parent) = path.parent() {
+        fs::create_dir_all(parent).map_err(|e| e.to_string())?;
+    }
+
+    let data = serde_json::to_string_pretty(accounts).map_err(|e| e.to_string())?;
+
+    fs::write(path, data).map_err(|e| e.to_string())
+}
+
+#[command]
+pub fn auth_create_link() -> Result<String, String> {
+    create_link().map_err(|e| e.to_string())
+}
+
+#[command]
+pub async fn auth_login(code: String) -> Result<MinecraftAccount, String> {
+    let client = Client::new();
+
+    let account = authenticate(code, &client)
+        .await
+        .map_err(|e| e.to_string())?;
+
+    let mut accounts = load_accounts();
+
+    // Replace if same UUID exists
+    accounts.retain(|a| a.uuid != account.uuid);
+    accounts.push(account.clone());
+
+    save_accounts(&accounts)?;
+
+    Ok(account)
+}
+
+#[command]
+pub async fn auth_refresh(uuid: String) -> Result<MinecraftAccount, String> {
+    let client = Client::new();
+    let mut accounts = load_accounts();
+
+    let account = accounts
+        .iter()
+        .find(|a| a.uuid == uuid)
+        .cloned()
+        .ok_or("Account not found")?;
+
+    let refreshed = refresh(account.refresh_token, &client)
+        .await
+        .map_err(|e| e.to_string())?;
+
+    accounts.retain(|a| a.uuid != uuid);
+    accounts.push(refreshed.clone());
+
+    save_accounts(&accounts)?;
+
+    Ok(refreshed)
+}
+
+#[command]
+pub fn auth_list() -> Result<Vec<MinecraftAccount>, String> {
+    Ok(load_accounts())
+}
+
+#[command]
+pub fn auth_remove(uuid: String) -> Result<(), String> {
+    let mut accounts = load_accounts();
+
+    accounts.retain(|a| a.uuid != uuid);
+
+    save_accounts(&accounts)
+}
+
+#[command]
+pub fn auth_validate(uuid: String) -> Result<bool, String> {
+    let accounts = load_accounts();
+
+    let account = accounts
+        .iter()
+        .find(|a| a.uuid == uuid)
+        .ok_or("Account not found")?;
+
+    Ok(validate(account.exp))
+}
+
+#[command]
+pub async fn auth_get_valid(uuid: String) -> Result<MinecraftAccount, String> {
+    let client = Client::new();
+    let mut accounts = load_accounts();
+
+    let account = accounts
+        .iter()
+        .find(|a| a.uuid == uuid)
+        .cloned()
+        .ok_or("Account not found")?;
+
+    if validate(account.exp) {
+        return Ok(account);
+    }
+
+    let refreshed = refresh(account.refresh_token, &client)
+        .await
+        .map_err(|e| e.to_string())?;
+
+    accounts.retain(|a| a.uuid != uuid);
+    accounts.push(refreshed.clone());
+
+    save_accounts(&accounts)?;
+
+    Ok(refreshed)
+}
diff --git a/src-tauri/src/launcher/mod.rs b/src-tauri/src/launcher/mod.rs
index 783e5ee..74a0df1 100644
--- a/src-tauri/src/launcher/mod.rs
+++ b/src-tauri/src/launcher/mod.rs
@@ -1,5 +1,6 @@
 pub mod downloader;
 pub mod install;
+pub mod auth;
 
 use directories::ProjectDirs;
 use lyceris::minecraft::{
diff --git a/src-tauri/src/main.rs b/src-tauri/src/main.rs
index b7f84c1..c5559e8 100644
--- a/src-tauri/src/main.rs
+++ b/src-tauri/src/main.rs
@@ -10,12 +10,22 @@ fn main() {
         .plugin(tauri_plugin_opener::init())
         .manage(Mutex::new(AppState::default()))
         .invoke_handler(tauri::generate_handler![
+            // Saturn Launcher Commands
             get_installed_mods,
             toggle_mod,
             install_mod,
             get_settings,
             update_settings,
-            saturn_launcher_lib::launcher::launch_game
+            // Launcher Commands
+            saturn_launcher_lib::launcher::launch_game,
+            // Auth Commands
+            saturn_launcher_lib::launcher::auth::auth_create_link,
+            saturn_launcher_lib::launcher::auth::auth_login,
+            saturn_launcher_lib::launcher::auth::auth_refresh,
+            saturn_launcher_lib::launcher::auth::auth_list,
+            saturn_launcher_lib::launcher::auth::auth_remove,
+            saturn_launcher_lib::launcher::auth::auth_validate,
+            saturn_launcher_lib::launcher::auth::auth_get_valid
         ])
         .run(tauri::generate_context!())
         .expect("error while running tauri application");