diff --git a/.gitignore b/.gitignore
index ab9811f..7aa067a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@ __pycache__
 /webmake.egg-info
 /.project
 /.pydevproject
+/.idea
 /tests/test_project/package-lock.json
 /webmake/package-lock.json
 /build
diff --git a/setup.py b/setup.py
index 0588a9e..9ff0b59 100644
--- a/setup.py
+++ b/setup.py
@@ -143,6 +143,7 @@ def run(self):
     # https://packaging.python.org/en/latest/requirements.html
     install_requires=[
         'watchdog>=0.8',
+        'six',
     ],
 
     # List additional groups of dependencies here (e.g. development
diff --git a/tests/test_project/webmakefile.py b/tests/test_project/webmakefile.py
index 9eb4b42..cf886b6 100644
--- a/tests/test_project/webmakefile.py
+++ b/tests/test_project/webmakefile.py
@@ -51,6 +51,9 @@ def custom_compiler(input_files, output_file, release):
     # Minify standalone JS. Concatenates in debug mode, minifies in release mode.
     api.minify_js(['www-dev/js/standalone.js'], 'www/js/standalone.js'),
 
+    # Minify AngularJS 1.x. Concatenates in debug mode, minifies and annotates Angular dependencies in release mode.
+    api.minify_js(['www-dev/angular-1.x/module.js'], 'www/angular-1.x/module.js', annotate_angular=True),
+
     # Concatenate standalone files with no further processing.
     api.concatenate(['www-dev/js/standalone.js'] * 2, 'www/js/standalone-x2.js'),
 
diff --git a/tests/test_project/www-dev/angular-1.x/module.js b/tests/test_project/www-dev/angular-1.x/module.js
new file mode 100644
index 0000000..5705330
--- /dev/null
+++ b/tests/test_project/www-dev/angular-1.x/module.js
@@ -0,0 +1,9 @@
+angular.module("WebmakeTest", [])
+  .factory("TestFactory", function () {
+    this.foo = function () {
+      alert("foo")
+    }
+  })
+  .controller("TestController", function (TestFactory) {
+    TestFactory.foo()
+  });
\ No newline at end of file
diff --git a/webmake/api.py b/webmake/api.py
index 09ebdaf..363ec1c 100644
--- a/webmake/api.py
+++ b/webmake/api.py
@@ -57,7 +57,7 @@ def copy_files(src_dir, dst_dir, filespec='*', recursive=False):
     }
 
 
-def minify_js(input_files, output_file):
+def minify_js(input_files, output_file, annotate_angular=False):
     """
     Minifies the input javascript files to the output file.
 
@@ -66,6 +66,7 @@ def minify_js(input_files, output_file):
     In debug mode this function just concatenates the files
     without minifying.
     """
+    from functools import partial
     from .modules import minify, utils
 
     if not isinstance(input_files, (list, tuple)):
@@ -73,7 +74,7 @@ def minify_js(input_files, output_file):
 
     return {
         'dependencies_fn': utils.no_dependencies,
-        'compiler_fn': minify.minify_js,
+        'compiler_fn': partial(minify.minify_js, annotate_angular=annotate_angular),
         'input': input_files,
         'output': output_file,
         'kwargs': {},
diff --git a/webmake/django/middleware.py b/webmake/django/middleware.py
index 68aabef..84056d3 100644
--- a/webmake/django/middleware.py
+++ b/webmake/django/middleware.py
@@ -43,6 +43,10 @@ def pre_process(self, deployment_settings, *args, **kwargs):
 BINFILE = POSSIBLE_BINFILES[0] if POSSIBLE_BINFILES else WEBMAKE_BIN
 
 
+class WebmakeRuntimeWarning(RuntimeWarning):
+    pass
+
+
 class WebmakeCompilerMiddleware:
     def __init__(self, get_response=None):
         self.get_response = get_response
@@ -53,7 +57,7 @@ def __call__(self, request):
 
     def process_request(self, request):
         if not settings.DEBUG:
-            warnings.warn('WebmakeCompilerMiddleware should not be used in production!', RuntimeWarning)
+            warnings.warn('WebmakeCompilerMiddleware should not be used in production!', WebmakeRuntimeWarning)
 
         cmd = ' '.join([BINFILE, '-m', WEBMAKEFILE])
         env = os.environ.copy()
diff --git a/webmake/modules/concat.py b/webmake/modules/concat.py
index 5938932..ed91217 100644
--- a/webmake/modules/concat.py
+++ b/webmake/modules/concat.py
@@ -1,6 +1,9 @@
 import os
+import six
 from . import utils
 
+FILE_HANDLE_KWARGS = {} if six.PY2 else dict(encoding='utf-8')
+
 
 def _trimpath(path):
     comps = []
@@ -24,9 +27,9 @@ def concatenate_input_files(input_files, output_file, release=False):
 
     try:
         utils.logv('>>> concat {} > {}'.format(' '.join(input_files), output_file))
-        with open(output_file, 'w') as output:
+        with open(output_file, 'w', **FILE_HANDLE_KWARGS) as output:
             for input_file in input_files:
-                with open(input_file, 'r') as input:
+                with open(input_file, 'r', **FILE_HANDLE_KWARGS) as input:
                     output.write(input.read())
 
                 if not release:
diff --git a/webmake/modules/copyfiles.py b/webmake/modules/copyfiles.py
index dbdd50e..5b33112 100644
--- a/webmake/modules/copyfiles.py
+++ b/webmake/modules/copyfiles.py
@@ -1,5 +1,4 @@
 import os
-import re
 import shutil
 from fnmatch import fnmatch
 from . import utils
diff --git a/webmake/modules/less.py b/webmake/modules/less.py
index ce52688..4da8b57 100644
--- a/webmake/modules/less.py
+++ b/webmake/modules/less.py
@@ -8,7 +8,7 @@
 
 def _read_less_imports(file):
     deps = []
-    with open(file) as f:
+    with open(file, encoding='utf-8') as f:
         less = f.read()
     imports = LESS_IMPORT_RE.findall(less)
     less_dir = os.path.dirname(file)
diff --git a/webmake/modules/minify.py b/webmake/modules/minify.py
index fcc1299..e39dd47 100644
--- a/webmake/modules/minify.py
+++ b/webmake/modules/minify.py
@@ -2,20 +2,32 @@
 from . import utils, concat
 
 
-def minify_js(input_files, output_file, release=False):
+def minify_js(input_files, output_file, release=False, annotate_angular=False):
     assert isinstance(input_files, (list, tuple))
 
     if not release:
         concat.concatenate_input_files(input_files, output_file, release=release)
         return
 
+    if annotate_angular:
+        # Rather than annotate several individual files (and having to creating temp files as well), it's
+        # easier to just concatenate the input_files right now, and then perform the annotation upon that
+        # one file. We must then update the `input_files` value accordingly, so that it gets passed into
+        # uglify correctly.
+        concat.concatenate_input_files(input_files, output_file, release=release)
+        input_files = [output_file]
+        try:
+            annotate_angular_injections(output_file, output_file)
+        except:
+            utils.ensure_deleted(output_file)
+            raise
+
     if output_file:
         utils.ensure_path_exists(os.path.dirname(output_file))
 
     cmdline = [
         utils.get_node_bin_path('uglify-es', 'bin', 'uglifyjs'),
         '--compress',
-        '--mangle',
         '-o',
         output_file,
         '--',
@@ -28,6 +40,20 @@ def minify_js(input_files, output_file, release=False):
         utils.ensure_deleted(output_file)
         raise
 
+def annotate_angular_injections(input_file, output_file):
+    cmdline = [
+        os.path.join(utils.get_node_bin_path('ng-annotate'), 'ng-annotate.js'),
+        '--add',
+        '-o',
+        output_file,
+    ]
+    cmdline.extend([input_file])
+
+    try:
+        utils.run_command(cmdline, 'Failed to annotate Angular injections to "{}"'.format(output_file), with_node=True)
+    except Exception as e:
+        utils.ensure_deleted(output_file)
+        raise
 
 def minify_css(input_files, output_file, release=False):
     assert isinstance(input_files, (list, tuple))
diff --git a/webmake/package.json b/webmake/package.json
index 2ffae28..908ad21 100644
--- a/webmake/package.json
+++ b/webmake/package.json
@@ -10,6 +10,7 @@
     "browserify": "^9.0.8",
     "cssmin": "^0.4.3",
     "less": "^2.7.3",
+    "ng-annotate": "1.x",
     "node-sass": "^4.12.0",
     "uglify-es": "^3.3.9"
   }