diff --git a/ipc.py b/ipc.py
new file mode 100644
index 0000000..da269d0
--- /dev/null
+++ b/ipc.py
@@ -0,0 +1,82 @@
+#!/usr/bin/python3
+
+import sys
+import socket
+import json
+import threading
+
+HOST = "127.0.0.1"
+PORT = 58592
+
+
+class IPC:
+    def __init__(self, app):
+        self.app = app
+
+        self.first_instance = not self.already_running()
+
+        self.server_thread = threading.Thread(target=self.server)
+        self.server_thread.daemon = True
+
+        if self.first_instance:
+            self.server_thread.start()
+
+        else:
+            self.send_open_file_message(sys.argv[1:])
+
+    def already_running(self):
+        try:
+            with socket.create_connection((HOST, PORT), timeout=1):
+                return True
+
+        except (ConnectionRefusedError, OSError):
+            return False
+
+    def server(self):
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as server_socket:
+            server_socket.bind((HOST, PORT))
+            server_socket.listen(1)
+
+            while True:
+                conn, addr = server_socket.accept()
+
+                with conn:
+                    data = conn.recv(1024)
+                    if data:
+                        message = data.decode('utf-8')
+
+                        self.evaluate_message(message)
+
+    def send(self, message):
+        try:
+            with socket.create_connection((HOST, PORT)) as client_socket:
+                client_socket.sendall(message.encode('utf-8'))
+
+        except Exception as error:
+            print("IPC-error:", error)
+
+    def evaluate_message(self, raw_message):
+        data_dict = json.loads(raw_message)
+        message = Message(data_dict["type"], data_dict["content"])
+
+        match message.type:
+            case "open_files":
+                self.app.open_files_queue += message.content
+
+    def send_open_file_message(self, filenames):
+        message = Message("open_files", filenames)
+
+        self.send(message.get_message_data())
+
+
+class Message:
+    def __init__(self, message_type: str, content):
+        self.type = message_type
+        self.content = content
+
+    def get_message_data(self):
+        data_dict = self.__dict__
+        data_dict = dict(filter(lambda pair: not callable(pair[1]), data_dict.items()))  # filter out functions
+        data = json.dumps(data_dict)
+
+        return data
diff --git a/main.py b/main.py
index 42b255a..52e3d64 100755
--- a/main.py
+++ b/main.py
@@ -1,25 +1,41 @@
 #!/usr/bin/python3
 
 import sys
+from PyQt6.QtCore import QTimer
 from wobbl_tools.data_file import load_dataclass_json
 from utils import Utils
 from file import File, FileActions
 from ui import GUI
 from settings import Settings
+from ipc import IPC
 
 
 class BreadEditor:
     def __init__(self):
-        self.settings = load_dataclass_json(Settings, "settings.json")
 
         self.utils = Utils(self)
+        self.settings = load_dataclass_json(Settings, f"{self.utils.editor_path}/settings.json")
+
         self.file_actions = FileActions(self)
+
+        self.ipc = IPC(self)
+        if not self.ipc.first_instance:
+            return
+
         self.gui = GUI(self)
 
         self.gui.connect_gui(self)
         self.open_files: dict[str, File] = {}
+        self.open_files_queue = []
+
+        self.files_queue_timer = QTimer(self.gui.QTMainWindow)
+        self.files_queue_timer.timeout.connect(self.utils.check_file_queue)
+        self.files_queue_timer.start(500)
 
     def run(self):
+        if not self.ipc.first_instance:
+            return
+
         self.gui.post_setup()
 
         self.utils.on_start()
diff --git a/utils.py b/utils.py
index f3da91e..24a2fe3 100644
--- a/utils.py
+++ b/utils.py
@@ -104,7 +104,7 @@ class Utils:
 
         self.app.settings.last_opened_files = open_files
 
-        self.app.settings.save("settings.json")
+        self.app.settings.save(f"{self.editor_path}/settings.json")
 
     def update_style_in_all_bit_editors(self):
         self.app.settings.highlight_ones = self.app.gui.main_window.highlightOnesSetting.isChecked()
@@ -129,3 +129,10 @@ class Utils:
             if os.path.isfile(file_path):
                 file = File(self.app, file_path, file_path.split("/")[-1])
                 self.app.open_files[file_path] = file
+
+    def check_file_queue(self):
+        if not len(self.app.open_files_queue) == 0:
+            filenames = self.app.open_files_queue
+            self.app.open_files_queue = []
+
+            self.load_files(filenames)