diff --git a/CHANGELOG.md b/CHANGELOG.md
index f8795c6..55a71a1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+* Support config file in `$XDG_CONFIG_HOME/brotab/brotab.env`:
+```env
+HTTP_IFACE=0.0.0.0
+MIN_HTTP_PORT=4625 
+MAX_HTTP_PORT=4635 
+```
+  This is useful if you want to change interface mediator is binding to.
+
 1.4.1 (2022-05-29)
 
 * Better syntax for navigate and update:
diff --git a/brotab/api.py b/brotab/api.py
index 23b0d69..b88fa58 100644
--- a/brotab/api.py
+++ b/brotab/api.py
@@ -16,9 +16,9 @@
 from urllib.request import Request
 from urllib.request import urlopen
 
+from brotab.env import http_iface
 from brotab.inout import MultiPartForm
 from brotab.inout import edit_tabs_in_editor
-from brotab.mediator.const import DEFAULT_HTTP_IFACE
 from brotab.operations import infer_all_commands
 from brotab.parallel import call_parallel
 from brotab.tab import parse_tab_lines
@@ -302,7 +302,7 @@ def api_must_ready(port: int, browser: str,
                    prefix='a',
                    client_timeout: float = 0.1,
                    startup_timeout: float = 1.0) -> SingleMediatorAPI:
-    client = HttpClient(DEFAULT_HTTP_IFACE, port, timeout=client_timeout)
+    client = HttpClient(http_iface(), port, timeout=client_timeout)
     api = SingleMediatorAPI(prefix=prefix, port=port, startup_timeout=startup_timeout, client=client)
     assert api.browser == browser
     return api
@@ -312,6 +312,7 @@ def int_tab_id(tab_id: str) -> int:
     """Convert from str(b.20.123) to int(123)"""
     return int(tab_id.split('.')[-1])
 
+
 class MultipleMediatorsAPI(object):
     """
     This API is designed to work with multiple mediators.
diff --git a/brotab/env.py b/brotab/env.py
new file mode 100644
index 0000000..a9ac7b6
--- /dev/null
+++ b/brotab/env.py
@@ -0,0 +1,36 @@
+from os import environ
+from os.path import exists
+from os.path import expanduser
+
+from brotab.files import slurp_lines
+from brotab.mediator.const import DEFAULT_HTTP_IFACE
+from brotab.mediator.const import DEFAULT_MAX_HTTP_PORT
+from brotab.mediator.const import DEFAULT_MIN_HTTP_PORT
+from brotab.mediator.log import mediator_logger
+
+CONFIG = environ.get('XDG_CONFIG_HOME', expanduser('~/.config'))
+DEFAULT_FILENAME = '{0}/brotab/brotab.env'.format(CONFIG)
+
+
+def http_iface():
+    return environ.get('HTTP_IFACE', DEFAULT_HTTP_IFACE)
+
+
+def min_http_port():
+    return environ.get('MIN_HTTP_PORT', DEFAULT_MIN_HTTP_PORT)
+
+
+def max_http_port():
+    return environ.get('MAX_HTTP_PORT', DEFAULT_MAX_HTTP_PORT)
+
+
+def load_dotenv(filename=None):
+    if filename is None: filename = DEFAULT_FILENAME
+    mediator_logger.info('Loading .env file: %s', filename)
+    if not exists(filename):
+        mediator_logger.info('No .env file found: %s', filename)
+        return
+    for line in slurp_lines(filename):
+        if not line or line.startswith('#'): continue
+        key, value = line.split('=', 1)
+        environ[key] = value
diff --git a/brotab/files.py b/brotab/files.py
new file mode 100644
index 0000000..468953b
--- /dev/null
+++ b/brotab/files.py
@@ -0,0 +1,22 @@
+import os
+import tempfile
+
+
+def slurp(filename):
+    with open(filename) as file_:
+        return file_.read()
+
+
+def slurp_lines(filename):
+    with open(filename) as file_:
+        return [line.strip() for line in file_.readlines()]
+
+
+def spit(filename, contents):
+    with open(filename, 'w', encoding='utf-8') as file_:
+        file_.write(contents)
+
+
+def in_temp_dir(filename) -> str:
+    temp_dir = tempfile.gettempdir()
+    return os.path.join(temp_dir, filename)
diff --git a/brotab/inout.py b/brotab/inout.py
index ad963eb..92d923d 100644
--- a/brotab/inout.py
+++ b/brotab/inout.py
@@ -3,8 +3,8 @@
 import os
 import socket
 import sys
-import tempfile
 import uuid
+from select import select
 from subprocess import CalledProcessError
 from subprocess import check_call
 from tempfile import NamedTemporaryFile
@@ -12,36 +12,13 @@
 from typing import Iterable
 from typing import Union
 
-from select import select
-
+from brotab.env import max_http_port
+from brotab.env import min_http_port
 from brotab.platform import get_editor
 
-MIN_MEDIATOR_PORT = 4625
-MAX_MEDIATOR_PORT = MIN_MEDIATOR_PORT + 10
-
-
-def slurp(filename):
-    with open(filename) as file_:
-        return file_.read()
-
-
-def slurp_lines(filename):
-    with open(filename) as file_:
-        return [line.strip() for line in file_.readlines()]
-
-
-def spit(filename, contents):
-    with open(filename, 'w', encoding='utf-8') as file_:
-        file_.write(contents)
-
-
-def in_temp_dir(filename) -> str:
-    temp_dir = tempfile.gettempdir()
-    return os.path.join(temp_dir, filename)
-
 
 def get_mediator_ports() -> Iterable:
-    return range(MIN_MEDIATOR_PORT, MAX_MEDIATOR_PORT)
+    return range(min_http_port(), max_http_port())
 
 
 def get_available_tcp_port(start=1025, end=65536, host='127.0.0.1'):
diff --git a/brotab/main.py b/brotab/main.py
index 46a42c0..70d30e3 100644
--- a/brotab/main.py
+++ b/brotab/main.py
@@ -69,7 +69,7 @@
 from brotab.const import DEFAULT_GET_WORDS_JOIN_WITH
 from brotab.const import DEFAULT_GET_WORDS_MATCH_REGEX
 from brotab.inout import get_mediator_ports
-from brotab.inout import in_temp_dir
+from brotab.files import in_temp_dir
 from brotab.inout import is_port_accepting_connections
 from brotab.inout import marshal
 from brotab.inout import read_stdin
diff --git a/brotab/mediator/brotab_mediator.py b/brotab/mediator/brotab_mediator.py
index 30e50c0..7236bc4 100755
--- a/brotab/mediator/brotab_mediator.py
+++ b/brotab/mediator/brotab_mediator.py
@@ -6,10 +6,11 @@
 import re
 import socket
 
+from brotab.env import http_iface
+from brotab.env import load_dotenv
 from brotab.inout import get_mediator_ports
 from brotab.inout import is_port_accepting_connections
 from brotab.mediator import sig
-from brotab.mediator.const import DEFAULT_HTTP_IFACE
 from brotab.mediator.const import DEFAULT_SHUTDOWN_POLL_INTERVAL
 from brotab.mediator.http_server import MediatorHttpServer
 from brotab.mediator.log import disable_click_echo
@@ -66,12 +67,13 @@ def mediator_main():
     monkeypatch_socket_bind_allow_port_reuse()
     disable_click_echo()
 
+    load_dotenv()
     port_range = list(get_mediator_ports())
     transport = default_transport()
     # transport = transport_with_timeout(sys.stdin.buffer, sys.stdout.buffer, DEFAULT_TRANSPORT_TIMEOUT)
     # transport = transport_with_timeout(sys.stdin.buffer, sys.stdout.buffer, 1.0)
     remote_api = default_remote_api(transport)
-    host = DEFAULT_HTTP_IFACE
+    host = http_iface()
     poll_interval = DEFAULT_SHUTDOWN_POLL_INTERVAL
 
     for port in port_range:
diff --git a/brotab/mediator/log.py b/brotab/mediator/log.py
index d9a6604..a349a49 100644
--- a/brotab/mediator/log.py
+++ b/brotab/mediator/log.py
@@ -2,7 +2,7 @@
 import logging.handlers
 from traceback import format_stack
 
-from brotab.inout import in_temp_dir
+from brotab.files import in_temp_dir
 
 
 def _init_logger(tag, filename: str):
diff --git a/brotab/tests/test_integration.py b/brotab/tests/test_integration.py
index faba530..7a69efc 100644
--- a/brotab/tests/test_integration.py
+++ b/brotab/tests/test_integration.py
@@ -13,6 +13,7 @@
 import pytest
 
 from brotab.api import api_must_ready
+from brotab.env import min_http_port
 from brotab.inout import get_available_tcp_port
 from brotab.inout import wait_net_service
 from brotab.mediator.const import DEFAULT_MIN_HTTP_PORT
@@ -144,7 +145,7 @@ def __init__(self):
         self._browser = Popen(self.CMD, shell=True,
                               cwd=self.CWD, preexec_fn=os.setsid)
         print('PID', self._browser.pid)
-        wait_net_service('localhost', DEFAULT_MIN_HTTP_PORT, TIMEOUT)
+        wait_net_service('localhost', min_http_port(), TIMEOUT)
         print('init done PID', self._browser.pid)
 
     def stop(self):
diff --git a/brotab/tests/test_main.py b/brotab/tests/test_main.py
index 3524f29..cd0d82b 100644
--- a/brotab/tests/test_main.py
+++ b/brotab/tests/test_main.py
@@ -6,13 +6,13 @@
 from uuid import uuid4
 
 from brotab.api import SingleMediatorAPI
-from brotab.inout import MIN_MEDIATOR_PORT
+from brotab.env import http_iface
+from brotab.env import min_http_port
+from brotab.files import in_temp_dir
+from brotab.files import spit
 from brotab.inout import get_available_tcp_port
-from brotab.inout import in_temp_dir
-from brotab.inout import spit
 from brotab.main import create_clients
 from brotab.main import run_commands
-from brotab.mediator.const import DEFAULT_HTTP_IFACE
 from brotab.mediator.http_server import MediatorHttpServer
 from brotab.mediator.remote_api import default_remote_api
 from brotab.mediator.transport import Transport
@@ -59,7 +59,7 @@ def __init__(self, prefix='a', port=None, remote_api=None):
         self.port = get_available_tcp_port() if port is None else port
         self.transport = MockedLoggingTransport()
         self.remote_api = default_remote_api(self.transport) if remote_api is None else remote_api
-        self.server = MediatorHttpServer(DEFAULT_HTTP_IFACE, self.port, self.remote_api, 0.050)
+        self.server = MediatorHttpServer(http_iface(), self.port, self.remote_api, 0.050)
         self.thread = self.server.run.in_thread()
         self.transport.received_extend(['mocked'])
         self.api = SingleMediatorAPI(prefix, port=self.port, startup_timeout=1)
@@ -128,7 +128,7 @@ def run_mocked_mediators(count, default_port_offset, delay):
     """
     assert count > 0
     print('Creating %d mediators' % count)
-    start_port = MIN_MEDIATOR_PORT + default_port_offset
+    start_port = min_http_port() + default_port_offset
     ports = range(start_port, start_port + count)
     mediators = [MockedMediator(letter, port, DummyBrowserRemoteAPI())
                  for i, letter, port in zip(range(count), ascii_letters, ports)]
@@ -147,7 +147,7 @@ def run_mocked_mediator_current_thread(port):
     """
     remote_api = DummyBrowserRemoteAPI()
     port = get_available_tcp_port() if port is None else port
-    server = MediatorHttpServer(DEFAULT_HTTP_IFACE, port, remote_api, 0.050)
+    server = MediatorHttpServer(http_iface(), port, remote_api, 0.050)
     server.run.here()
 
 
diff --git a/brotab/tests/test_mediator.py b/brotab/tests/test_mediator.py
deleted file mode 100644
index 1fa9a25..0000000
--- a/brotab/tests/test_mediator.py
+++ /dev/null
@@ -1,138 +0,0 @@
-import os
-import signal
-from contextlib import contextmanager
-from multiprocessing import Barrier
-from multiprocessing import Process
-from unittest import TestCase
-
-from brotab.api import api_must_ready
-from brotab.inout import get_available_tcp_port
-from brotab.mediator import sig
-from brotab.mediator.const import DEFAULT_HTTP_IFACE
-from brotab.mediator.http_server import MediatorHttpServer
-from brotab.mediator.log import mediator_logger
-from brotab.mediator.remote_api import default_remote_api
-# from brotab.mediator.transport import transport_with_timeout
-from brotab.wait import Waiter
-
-
-# class MockedPiperMediator:
-#     def __init__(self, prefix='a', port=None, remote_api=None):
-#         mediator_logger.info('starting mediator pid=%s', os.getpid())
-#         self.prefix = prefix
-#         self.port = get_available_tcp_port() if port is None else port
-#         input_r, input_w = os.pipe()
-#         output_r, output_w = os.pipe()
-#         self.transport_browser = transport_with_timeout(output_r, input_w, 0.050)
-#         self.transport_mediator = transport_with_timeout(input_r, output_w, 0.050)
-#         self.remote_api = default_remote_api(self.transport_mediator) if remote_api is None else remote_api
-#         self.server = MediatorHttpServer(DEFAULT_HTTP_IFACE, self.port, self.remote_api, poll_interval=0.050)
-#         self.thread = None
-#         self.api = None
-#
-#     def start(self):
-#         self.thread = self.server.run.in_thread()
-#         self.transport_browser.send('mocked')
-#
-#     def wait_api_ready(self):
-#         self.api = api_must_ready(port=self.port, browser='mocked', prefix=self.prefix,
-#                                   client_timeout=0.1, startup_timeout=1)
-#
-#     def join(self):
-#         # sig.setup(lambda: server.run.shutdown(join=False))
-#         self.server.run.parent_watcher(self.thread.is_alive, interval=0.050)  # this is crucial
-#         self.thread.join()
-#
-#     def __enter__(self):
-#         return self
-#
-#     def __exit__(self, type_, value, tb):
-#         self.join()
-#
-#
-# class TestMediatorThreadTerminates(TestCase):
-#     def setUp(self):
-#         self.mediator = MockedPiperMediator()
-#         self.mediator.start()
-#         self.mediator.wait_api_ready()
-#
-#     def tearDown(self):
-#         pass
-#
-#     def test_if_cannot_read(self):
-#         self.mediator.api.list_tabs([])
-#         self.mediator.join()  # this should complete without manual shutdown
-#
-#     def test_if_cannot_write(self):
-#         self.mediator.transport_browser.send(['1.1\ttitle\turl'])  # make reads work
-#         self.mediator.transport_browser.close()
-#         self.mediator.api.list_tabs([])
-#         self.mediator.join()  # this should complete without manual shutdown
-#
-#
-# class TestMediatorProcessTerminates(TestCase):
-#     def test_when_parent_died(self):
-#         port = get_available_tcp_port()
-#         mediator_logger.info('starting test pid=%s', os.getpid())
-#         kill_parent = Barrier(2)
-#
-#         def run_threaded_mediator():
-#             mediator = MockedPiperMediator(port=port)
-#             mediator.start()
-#             mediator.join()
-#
-#         def run_doomed_parent_browser():
-#             mediator_logger.info('doomed_parent_browser pid=%s', os.getpid())
-#             mediator_process = Process(target=run_threaded_mediator)
-#             mediator_process.start()
-#             mediator_process.join()
-#
-#         def on_sig_child(signum, frame):
-#             pid, status = os.wait()
-#             mediator_logger.info('reaped child signum=%s pid=%s status=%s', signum, pid, status)
-#
-#         def run_supervisor():
-#             signal.signal(signal.SIGCHLD, on_sig_child)
-#             doomed_parent_browser = Process(target=run_doomed_parent_browser)
-#             doomed_parent_browser.start()
-#             kill_parent.wait()
-#             doomed_parent_browser.terminate()
-#             doomed_parent_browser.join()
-#
-#         signal.signal(signal.SIGCHLD, on_sig_child)
-#         supervisor = Process(target=run_supervisor)
-#         supervisor.start()
-#         api = api_must_ready(port, 'mocked')
-#
-#         # kill parent and expect mediator to terminate as well
-#         kill_parent.wait()
-#         self.assertTrue(Waiter(api.pid_not_ready).wait(timeout=1.0))
-#         supervisor.join()
-#
-#     @contextmanager
-#     def run_as_child_process(self):
-#         port = get_available_tcp_port()
-#         mediator_logger.info('starting test pid=%s', os.getpid())
-#
-#         def run_threaded_mediator():
-#             mediator = MockedPiperMediator(port=port)
-#             mediator.start()
-#             sig.setup(lambda: mediator.server.run.shutdown(join=False))
-#             mediator.join()
-#
-#         mediator_process = Process(target=run_threaded_mediator)
-#         mediator_process.start()
-#         api = api_must_ready(port, 'mocked')
-#
-#         yield mediator_process
-#
-#         self.assertTrue(Waiter(api.pid_not_ready).wait(timeout=1.0))
-#         mediator_process.join()
-#
-#     def test_when_sigint_received(self):
-#         with self.run_as_child_process() as mediator_process:
-#             os.kill(mediator_process.pid, signal.SIGINT)
-#
-#     def test_when_sigterm_received(self):
-#         with self.run_as_child_process() as mediator_process:
-#             os.kill(mediator_process.pid, signal.SIGTERM)