diff --git a/NOTICE b/NOTICE
index 3ed05b8..caf000f 100644
--- a/NOTICE
+++ b/NOTICE
@@ -15,6 +15,9 @@ license. For details, see https://github.com/testing-cabal/mock.
 This product bundles glog 0.3.1 which is available under a "2-clause BSD"
 license.  For details, see https://github.com/benley/python-glog.
 
+This product bundles python-daemon 2.2.0 which is available under an "Apache"
+license. For details see https://pagure.io/python-daemon.
+
 This product uses dumb-init which is available under an "MIT" license. For
 details, see https://github.com/Yelp/dumb-init.
 Copyright (c) 2015 Yelp, Inc.
diff --git a/README.md b/README.md
index 0bfea6b..712cfc5 100644
--- a/README.md
+++ b/README.md
@@ -38,13 +38,15 @@ pip3 install prometheus_speedtest
 ### Usage
 
 ```
-usage: prometheus_speedtest.py [-h] [-p port]
+usage: prometheus_speedtest [-h] [-d] [-p port]
 
 Instrument speedtest.net speedtests from Prometheus.
 
 optional arguments:
   -h, --help            show this help message and exit
-  -p port, --port port  port to listen on.
+  -d, --daemon          Run prometheus_speedtest in the background. (default:
+                        False)
+  -p port, --port port  port to listen on. (default: 8080)
 ```
 
 ### Integrating with Prometheus
@@ -169,3 +171,4 @@ file for details.
 * The Prometheus team <https://prometheus.io>
 * Testing in Python team <http://lists.idyll.org/listinfo/testing-in-python>
 * Benjamin Staffin [python-glog](https://github.com/benley/python-glog)
+* Ben Finney [python-daemon](https://pypi.org/project/python-daemon)
diff --git a/prometheus_speedtest.py b/prometheus_speedtest.py
index d901262..461430e 100755
--- a/prometheus_speedtest.py
+++ b/prometheus_speedtest.py
@@ -5,13 +5,21 @@
 import http
 import socketserver
 
+import daemon
 import glog as logging
 import prometheus_client
 from prometheus_client import core
 import speedtest
 
 PARSER = argparse.ArgumentParser(
-    description='Instrument speedtest.net speedtests from Prometheus.')
+    description='Instrument speedtest.net speedtests from Prometheus.',
+    formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+PARSER.add_argument(
+    '-d',
+    '--daemon',
+    action='store_true',
+    default=False,
+    help='Run prometheus_speedtest in the background.')
 PARSER.add_argument(
     '-p',
     '--port',
@@ -20,6 +28,8 @@
     type=int,
     help='port to listen on.')
 
+FLAGS = PARSER.parse_args()
+
 
 class PrometheusSpeedtest:
     """Enapsulates behavior performing and reporting results of speedtests."""
@@ -95,8 +105,6 @@ def collect(self):
 
 def main():
     """Entry point for prometheus_speedtest.py."""
-    flags = PARSER.parse_args()
-
     registry = core.CollectorRegistry(auto_describe=False)
     registry.register(SpeedtestCollector())
     metrics_handler = prometheus_client.MetricsHandler.factory(registry)
@@ -106,11 +114,15 @@ def main():
     threading_http_server = type(
         'ThreadingHTTPServer',
         (socketserver.ThreadingMixIn, http.server.HTTPServer), {})
-    server = threading_http_server(('', flags.port), metrics_handler)
+    server = threading_http_server(('', FLAGS.port), metrics_handler)
 
-    logging.info('Starting HTTP server on port %s', flags.port)
+    logging.info('Starting HTTP server on port %s', FLAGS.port)
     server.serve_forever()
 
 
 if __name__ == '__main__':
-    main()
+    if FLAGS.daemon:
+        with daemon.DaemonContext():
+            main()
+    else:
+        main()
diff --git a/prometheus_speedtest_test.py b/prometheus_speedtest_test.py
index ccd21b1..75857a0 100755
--- a/prometheus_speedtest_test.py
+++ b/prometheus_speedtest_test.py
@@ -57,8 +57,7 @@ def test_collect(mock_metric):
         collections.deque(collector.collect())
 
         mock_metric.assert_has_calls(
-            [mock.call(
-                labels=[], value=value) for value in speedtest_results])
+            [mock.call(labels=[], value=value) for value in speedtest_results])
 
 
 if __name__ == '__main__':
diff --git a/requirements.txt b/requirements.txt
index 3684aab..064e852 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,3 +2,4 @@ glog>=0.3.1
 mock>=2.0.0 
 prometheus_client>=0.4.2  
 speedtest-cli>=2.0.2
+python-daemon>=2.2.0
diff --git a/setup.py b/setup.py
index 3ca236d..82e72db 100644
--- a/setup.py
+++ b/setup.py
@@ -45,6 +45,7 @@ def read_file(rel_path):
         'glog>=0.3.1',
         'mock>=2.0.0',
         'prometheus_client>=0.3.1',
+        'python-daemon>=2.2.0',
         'speedtest-cli>=2.0.2',
     ],
     keywords=['prometheus', 'monitoring', 'speedtest', 'speedtest.net'],
diff --git a/version.txt b/version.txt
index 0d91a54..1d0ba9e 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-0.3.0
+0.4.0