diff --git a/jupyter_server/serverapp.py b/jupyter_server/serverapp.py
index 0f64d830b5..ba7562912f 100755
--- a/jupyter_server/serverapp.py
+++ b/jupyter_server/serverapp.py
@@ -4,9 +4,6 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.
 
-from __future__ import absolute_import, print_function
-
-import jupyter_server
 import binascii
 import datetime
 import errno
@@ -70,19 +67,19 @@
     __version__,
 )
 
-from .base.handlers import MainHandler, RedirectWithParams, Template404
-from .log import log_request
-from .services.kernels.kernelmanager import MappingKernelManager, AsyncMappingKernelManager
-from .services.config import ConfigManager
-from .services.contents.manager import AsyncContentsManager, ContentsManager
-from .services.contents.filemanager import AsyncFileContentsManager, FileContentsManager
-from .services.contents.largefilemanager import LargeFileManager
-from .services.sessions.sessionmanager import SessionManager
-from .gateway.managers import GatewayKernelManager, GatewayKernelSpecManager, GatewaySessionManager, GatewayClient
+from jupyter_server.base.handlers import MainHandler, RedirectWithParams, Template404
+from jupyter_server.log import log_request
+from jupyter_server.services.kernels.kernelmanager import MappingKernelManager, AsyncMappingKernelManager
+from jupyter_server.services.config import ConfigManager
+from jupyter_server.services.contents.manager import AsyncContentsManager, ContentsManager
+from jupyter_server.services.contents.filemanager import AsyncFileContentsManager, FileContentsManager
+from jupyter_server.services.contents.largefilemanager import LargeFileManager
+from jupyter_server.services.sessions.sessionmanager import SessionManager
+from jupyter_server.gateway.managers import GatewayKernelManager, GatewayKernelSpecManager, GatewaySessionManager, GatewayClient
 
-from .auth.login import LoginHandler
-from .auth.logout import LogoutHandler
-from .base.handlers import FileFindHandler
+from jupyter_server.auth.login import LoginHandler
+from jupyter_server.auth.logout import LogoutHandler
+from jupyter_server.base.handlers import FileFindHandler
 
 from traitlets.config import Config
 from traitlets.config.application import catch_config_error, boolean_flag
@@ -102,8 +99,8 @@
 from jupyter_core.paths import jupyter_runtime_dir, jupyter_path
 from jupyter_server._sysinfo import get_sys_info
 
-from ._tz import utcnow, utcfromtimestamp
-from .utils import (
+from jupyter_server._tz import utcnow, utcfromtimestamp
+from jupyter_server.utils import (
     url_path_join,
     check_pid,
     url_escape,
@@ -118,7 +115,7 @@
 
 # Tolerate missing terminado package.
 try:
-    from .terminal import TerminalManager
+    from jupyter_server.terminal import TerminalManager
     terminado_available = True
 except ImportError:
     terminado_available = False
@@ -152,6 +149,8 @@
     view=['jupyter_server.view.handlers']
 )
 
+DEFAULT_SERVER_PORT = 8888
+
 #-----------------------------------------------------------------------------
 # Helper functions
 #-----------------------------------------------------------------------------
@@ -400,7 +399,7 @@ def _config_file_default(self):
         return os.path.join(self.config_dir, 'jupyter_server_config.json')
 
     def start(self):
-        from .auth.security import set_password
+        from jupyter_server.auth.security import set_password
         set_password(config_file=self.config_file)
         self.log.info("Wrote hashed password to %s" % self.config_file)
 
@@ -456,8 +455,8 @@ class JupyterServerStopApp(JupyterApp):
     version = __version__
     description = "Stop currently running Jupyter server for a given port"
 
-    port = Integer(8888, config=True,
-        help="Port of the server to be killed. Default 8888")
+    port = Integer(DEFAULT_SERVER_PORT, config=True,
+        help=f"Port of the server to be killed. Default {DEFAULT_SERVER_PORT}")
 
     def parse_command_line(self, argv=None):
         super(JupyterServerStopApp, self).parse_command_line(argv)
@@ -723,14 +722,27 @@ def _valdate_ip(self, proposal):
         or containerized setups for example).""")
     )
 
-    port = Integer(8888, config=True,
-        help=_i18n("The port the Jupyter server will listen on.")
+    port_env = 'JUPYTER_PORT'
+    port_default_value = DEFAULT_SERVER_PORT
+    port = Integer(port_default_value, config=True,
+        help=_i18n("The port the server will listen on (env: JUPYTER_PORT).")
     )
 
-    port_retries = Integer(50, config=True,
-        help=_i18n("The number of additional ports to try if the specified port is not available.")
+    @default('port')
+    def port_default(self):
+        return int(os.getenv(self.port_env, self.port_default_value))
+
+    port_retries_env = 'JUPYTER_PORT_RETRIES'
+    port_retries_default_value = 50
+    port_retries = Integer(port_retries_default_value, config=True,
+        help=_i18n("The number of additional ports to try if the specified port is not "
+               "available (env: JUPYTER_PORT_RETRIES).")
     )
 
+    @default('port_retries')
+    def port_retries_default(self):
+        return int(os.getenv(self.port_retries_env, self.port_retries_default_value))
+
     certfile = Unicode(u'', config=True,
         help=_i18n("""The full path to an SSL/TLS certificate file.""")
     )
@@ -1558,7 +1570,7 @@ def init_terminals(self):
             return
 
         try:
-            from .terminal import initialize
+            from jupyter_server.terminal import initialize
             initialize(self.web_app, self.root_dir, self.connection_url, self.terminado_settings)
             self.terminals_available = True
         except ImportError as e:
@@ -2077,7 +2089,7 @@ def start_app(self):
         for line in self.running_server_info(kernel_count=False).split("\n"):
             info(line)
         info(_i18n("Use Control-C to stop this server and shut down all kernels (twice to skip confirmation)."))
-        if 'dev' in jupyter_server.__version__:
+        if 'dev' in __version__:
             info(_i18n("Welcome to Project Jupyter! Explore the various tools available"
                  " and their corresponding documentation. If you are interested"
                  " in contributing to the platform, please visit the community"