diff --git a/.env b/.env
new file mode 100644
index 0000000..7f22c38
--- /dev/null
+++ b/.env
@@ -0,0 +1 @@
+FEDIPLAY_API_BASE_URL=https://cybre.space
diff --git a/README.md b/README.md
index 09df9c2..e9df900 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ A Mastodon client that automatically plays your friends' music as they toot link
 
 You'll need `ffplay` from [FFmpeg](https://ffmpeg.org/) to actually play music. On macOS, `ffplay` is part of the Homebrew ffmpeg package, but you need to build it with `brew install ffmpeg --with-sdl2`.
 
-Edit `API_BASE_URL` at the top of `fediplay.py` so it points to your Mastodon instance.
+Edit `.env` and set `FEDIPLAY_API_BASE_URL` to your Mastodon instance.
 
 Use `pipenv install` from [Pipenv](https://docs.pipenv.org/) to install the Python dependencies.
 
diff --git a/fediplay.py b/fediplay.py
index e793b5c..a5bca3f 100644
--- a/fediplay.py
+++ b/fediplay.py
@@ -1,5 +1,3 @@
-API_BASE_URL = 'https://cybre.space'
-
 from subprocess import run
 from threading import Thread, Lock
 
@@ -94,20 +92,26 @@ def extract_links(toot):
     return [link.attrib['href'] for link in all_links if not has_external_link_class(link.attrib.get('class', ''))]
 
 def main():
-    import os
     from getpass import getpass
+    from os import environ, path
+    from sys import exit
 
-    if not os.path.exists('clientcred.secret'):
+    api_base_url = environ.get('FEDIPLAY_API_BASE_URL')
+    if not api_base_url:
+        print('FEDIPLAY_API_BASE_URL environment variable not set')
+        exit(1)
+
+    if not path.exists('clientcred.secret'):
         print('==> No clientcred.secret; registering application')
-        register(API_BASE_URL)
+        register(api_base_url)
 
-    if not os.path.exists('usercred.secret'):
+    if not path.exists('usercred.secret'):
         print('==> No usercred.secret; logging in')
         email = input('Email: ')
         password = getpass('Password: ')
-        login(API_BASE_URL, email, password)
+        login(api_base_url, email, password)
 
-    stream(API_BASE_URL)
+    stream(api_base_url)
 
 if __name__ == '__main__':
     main()