diff --git a/src/command_handler.h b/src/command_handler.h
index a17999f..e4901f5 100644
--- a/src/command_handler.h
+++ b/src/command_handler.h
@@ -40,6 +40,7 @@ namespace globals
     extern bool                   g_FirstLogin;
     extern std::string            g_TrustToken;
     extern bool                   g_TrustThisComputer;
+    extern std::string            g_LoginToken;
 } // namespace globals
 
 #include "defines.h"
@@ -161,6 +162,19 @@ bool handleLoginCommand(int8_t command, json& login_reply_json, uint32_t& accoun
             return false;
         }
 
+        // LOGIN_ERROR_LAUNCH_TOKEN_INVALID
+        case 0x0014:
+        {
+            // Single-use and short-lived; invalid means it was already used or expired.
+            globals::g_LoginToken.clear();
+            xiloader::console::output(xiloader::color::error, "==========================================================");
+            xiloader::console::output(xiloader::color::error, "Launch token invalid or expired (session expired).");
+            xiloader::console::output(xiloader::color::error, "Please log in again from the launcher.");
+            xiloader::console::output(xiloader::color::error, "==========================================================");
+
+            return false;
+        }
+
         // LOGIN_SUCCESS_CREATE_TOTP
         case 0x0010:
         {
diff --git a/src/main.cpp b/src/main.cpp
index 9e75c86..35d7422 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -60,6 +60,7 @@ namespace globals
     bool                   g_FirstLogin        = false;                       // set to true when --user --pass are both set to allow for autologin
     std::string            g_TrustToken        = "";                          // trust token loaded from disk or received from server
     bool                   g_TrustThisComputer = false;                       // user checkbox / CLI flag for "trust this computer"
+    std::string            g_LoginToken        = "";                          // single-use launch token from the launcher; sent in place of password + OTP
 
     char* g_CharacterList = NULL;  // Pointer to the character list data being sent from the server.
     bool  g_IsRunning     = false; // Flag to determine if the network threads should hault.
@@ -569,8 +570,13 @@ int __cdecl main(int argc, char* argv[])
                 globals::g_Username = maybeUsername.value_or(globals::g_Username);
                 globals::g_Password = maybePassword.value_or(globals::g_Password);
 
-                // Set autologin if it isn't set already
-                if (maybeUsername.has_value() && maybePassword.has_value())
+                // Optional single-use launch token; sent in place of password + OTP.
+                globals::g_LoginToken = jsonGet<std::string>(jsonData, "login_token").value_or(globals::g_LoginToken);
+
+                // A launch-token boot has a username + token but no password, so
+                // it also enables autologin.
+                if (maybeUsername.has_value() &&
+                    (maybePassword.has_value() || !globals::g_LoginToken.empty()))
                 {
                     globals::g_FirstLogin = true;
                 }
diff --git a/src/network.cpp b/src/network.cpp
index 7b6c3df..814713f 100644
--- a/src/network.cpp
+++ b/src/network.cpp
@@ -51,6 +51,7 @@ namespace globals
     extern bool                   g_FirstLogin;
     extern std::string            g_TrustToken;
     extern bool                   g_TrustThisComputer;
+    extern std::string            g_LoginToken;
 }
 
 // mbed tls state
@@ -493,10 +494,17 @@ namespace xiloader
         login_json["version"]      = globals::g_VersionNumber;
         login_json["command"]      = command;
 
-        if (command == 0x10) // Only send trust fields for login
+        if (command == 0x10) // Only send trust/launch fields for login
         {
             login_json["trust_token"]        = globals::g_TrustToken;
             login_json["trust_this_computer"] = globals::g_TrustThisComputer;
+
+            // Optional single-use launch token; xi_connect consumes it in place
+            // of password + OTP (password may be empty).
+            if (!globals::g_LoginToken.empty())
+            {
+                login_json["login_token"] = globals::g_LoginToken;
+            }
         }
 
         std::string str          = login_json.dump();