diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 0000000..f49e149
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,4 @@
+.git
+.venv
+ui/.angular
+ui/node_modules
diff --git a/README.md b/README.md
index 7f367c5..bfdfd08 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ Certain values can be set via environment variables, using the `-e` parameter on
 * __DOWNLOAD_DIR__: path to where the downloads will be saved. Defaults to `/downloads` in the docker image, and `.` otherwise.
 * __AUDIO_DOWNLOAD_DIR__: path to where audio-only downloads will be saved, if you wish to separate them from the video downloads. Defaults to the value of `DOWNLOAD_DIR`.
 * __CUSTOM_DIRS__: whether to enable downloading videos into custom directories within the __DOWNLOAD_DIR__ (or __AUDIO_DOWNLOAD_DIR__). When enabled, a drop-down appears next to the Add button to specify the download directory. Defaults to `true`.
-* __CREATE_CUSTOM_DIRS__: whether to support automatically creating directories within the __DOWNLOAD_DIR__ (or __AUDIO_DOWNLOAD_DIR__) if they do not exist. When enabled, the download directory selector becomes supports free-text input, and the specified directory will be created recursively. Defaults to `false`.
+* __CREATE_CUSTOM_DIRS__: whether to support automatically creating directories within the __DOWNLOAD_DIR__ (or __AUDIO_DOWNLOAD_DIR__) if they do not exist. When enabled, the download directory selector becomes supports free-text input, and the specified directory will be created recursively. Defaults to `true`.
 * __STATE_DIR__: path to where the queue persistence files will be saved. Defaults to `/downloads/.metube` in the docker image, and `.` otherwise.
 * __URL_PREFIX__: base path for the web server (for use when hosting behind a reverse proxy). Defaults to `/`.
 * __OUTPUT_TEMPLATE__: the template for the filenames of the downloaded videos, formatted according to [this spec](https://github.com/yt-dlp/yt-dlp/blob/master/README.md#output-template). Defaults to `%(title)s.%(ext)s`.
diff --git a/app/main.py b/app/main.py
index 27fc2b7..46f4424 100644
--- a/app/main.py
+++ b/app/main.py
@@ -26,12 +26,19 @@ class Config:
         'YTDL_OPTIONS': '{}',
     }
 
+    _BOOLEAN = ('CUSTOM_DIRS', 'CREATE_CUSTOM_DIRS')
+
     def __init__(self):
         for k, v in self._DEFAULTS.items():
             setattr(self, k, os.environ[k] if k in os.environ else v)
         for k, v in self.__dict__.items():
             if v.startswith('%%'):
                 setattr(self, k, getattr(self, v[2:]))
+            if k in self._BOOLEAN:
+                if v not in ('true', 'false', 'True', 'False', 'on', 'off', '1', '0'):
+                    log.error(f'Environment variable "{k}" is set to a non-boolean value "{v}"')
+                    sys.exit(1)
+                setattr(self, k, v in ('true', 'True', 'on', '1'))
         if not self.URL_PREFIX.endswith('/'):
             self.URL_PREFIX += '/'
         try:
diff --git a/app/ytdl.py b/app/ytdl.py
index 266de10..0a74b14 100644
--- a/app/ytdl.py
+++ b/app/ytdl.py
@@ -236,14 +236,14 @@ class DownloadQueue:
                 # Keep consistent with frontend
                 base_directory = self.config.DOWNLOAD_DIR if (quality != 'audio' and format != 'mp3') else self.config.AUDIO_DOWNLOAD_DIR
                 if folder:
-                    if self.config.CUSTOM_DIRS != 'true':
+                    if not self.config.CUSTOM_DIRS:
                         return {'status': 'error', 'msg': f'A folder for the download was specified but CUSTOM_DIRS is not true in the configuration.'}
                     dldirectory = os.path.realpath(os.path.join(base_directory, folder))
                     real_base_directory = os.path.realpath(base_directory)
                     if not dldirectory.startswith(real_base_directory):
                         return {'status': 'error', 'msg': f'Folder "{folder}" must resolve inside the base download directory "{real_base_directory}"'}
                     if not os.path.isdir(dldirectory):
-                        if self.config.CREATE_CUSTOM_DIRS != 'true':
+                        if not self.config.CREATE_CUSTOM_DIRS:
                             return {'status': 'error', 'msg': f'Folder "{folder}" for download does not exist inside base directory "{real_base_directory}", and CREATE_CUSTOM_DIRS is not true in the configuration.'}
                         os.makedirs(dldirectory, exist_ok=True)
                 else:
diff --git a/ui/src/app/app.component.ts b/ui/src/app/app.component.ts
index 7ef7da4..d4a1270 100644
--- a/ui/src/app/app.component.ts
+++ b/ui/src/app/app.component.ts
@@ -82,11 +82,11 @@ export class AppComponent implements AfterViewInit {
   }
 
   showAdvanced() {
-    return this.downloads.configuration['CUSTOM_DIRS'] == 'true';
+    return this.downloads.configuration['CUSTOM_DIRS'];
   }
 
   allowCustomDir(tag: string) {
-    if (this.downloads.configuration['CREATE_CUSTOM_DIRS'] == 'true') {
+    if (this.downloads.configuration['CREATE_CUSTOM_DIRS']) {
       return tag;
     }
     return false;