diff --git a/README.md b/README.md
index bb9bacfbf..1ebb9326c 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,22 @@ on your `PATH`.
 
 `pytest test/`
 
+# Manual Testing
+
+The port 8000 of the docker environment and the system are automatically binded when ``./run_docker`` is run.
+
+This can be used to test the ``pyodide`` builds running within the docker environment using external browser
+programs of the system.
+
+To do this, simply run ``./bin/pyodide serve``
+
+This serves the ``build`` directory of the ``pyodide`` project on port 8000.
+
+* To serve a different directory, use the ``--build_dir`` argument followed the path of the directory
+* To serve on a different port, use the ``--port`` argument followed by the desired port number
+
+Make sure that the port passed in ``--port`` argument is same as the one defined as ``DOCKER_PORT`` in the ``run_docker`` script.
+
 # Benchmarking
 
 Install the same dependencies as for testing.
diff --git a/pyodide_build/serve.py b/pyodide_build/serve.py
index 813727706..6d475438b 100644
--- a/pyodide_build/serve.py
+++ b/pyodide_build/serve.py
@@ -37,9 +37,9 @@ def main(args):
     build_dir = args.build_dir
     port = args.port
     httpd = server(port)
+    os.chdir(build_dir)
+    print("serving from {0} at localhost:".format(build_dir) + str(port))
     try:
-        os.chdir(build_dir)
-        print("serving from {0} at localhost:".format(build_dir) + str(port))
         httpd.serve_forever()
     except KeyboardInterrupt:
         print("\n...shutting down http server")
diff --git a/run_docker b/run_docker
index df5883829..15ed485f3 100755
--- a/run_docker
+++ b/run_docker
@@ -1,2 +1,5 @@
 #!/bin/sh
-docker run -p 8000:8000 --rm -v $PWD:/src --user root -e NB_UID=$UID -e NB_GID=$GID -it iodide/pyodide-env:0.3.1 /bin/bash
+DOCKER_PORT=8000
+SYSTEM_PORT=8000
+
+docker run -p $SYSTEM_PORT:$DOCKER_PORT --rm -v $PWD:/src --user root -e NB_UID=$UID -e NB_GID=$GID -it iodide/pyodide-env:0.3.1 /bin/bash