diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 00000000..687b11ce
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,4 @@
+# 1.0.5
+* Now using `package:merge_map` to merge configurations. Resolves
+[#5](https://github.com/angel-dart/configuration/issues/5).
+* You can now specify a custom `envPath`.
\ No newline at end of file
diff --git a/README.md b/README.md
index b588af7e..163bb883 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,30 @@ main() async {
 The former will allow you to search in a directory other than `config`, and the latter lets you
 override `$ANGEL_ENV` by specifying a specific configuration name to look for (i.e. `production`).
 
+This package uses
+[`package:merge_map`](https://github.com/thosakwe/merge_map)
+internally, so existing configurations can be deeply merged.
+
+Example:
+
+```yaml
+# default.yaml
+foo:
+  bar: baz
+  quux: hello
+  
+# production.yaml
+foo:
+  quux: goodbye
+  yellow: submarine
+  
+# Propagates to:
+foo:
+  bar: baz
+  quux: goodbye
+  yellow: submarine
+```
+
 **In the Browser**
 
 You can easily load configuration values within your client-side app,
diff --git a/analysis_options.yaml b/analysis_options.yaml
new file mode 100644
index 00000000..518eb901
--- /dev/null
+++ b/analysis_options.yaml
@@ -0,0 +1,2 @@
+analyzer:
+  strong-mode: true
\ No newline at end of file
diff --git a/lib/angel_configuration.dart b/lib/angel_configuration.dart
index 6e451095..4ac626ed 100644
--- a/lib/angel_configuration.dart
+++ b/lib/angel_configuration.dart
@@ -3,6 +3,7 @@ library angel_configuration;
 import 'dart:io';
 import 'package:angel_framework/angel_framework.dart';
 import 'package:dotenv/dotenv.dart' as dotenv;
+import 'package:merge_map/merge_map.dart';
 import 'package:yaml/yaml.dart';
 
 final RegExp _equ = new RegExp(r'=$');
@@ -42,9 +43,20 @@ _loadYamlFile(Angel app, File yamlFile, Map<String, String> env) async {
           'WARNING: The configuration at "${yamlFile.absolute.path}" is not a Map. Refusing to load it.');
       return;
     }
+
+    Map<String, dynamic> out = {};
+
     for (String key in config.keys) {
-      app.properties[key] = _applyEnv(config[key], env ?? {});
+      out[key] = _applyEnv(config[key], env ?? {});
     }
+
+    app.properties.addAll(mergeMap(
+      [
+        app.properties,
+        out,
+      ],
+      acceptNull: true,
+    ));
   }
 }
 
@@ -71,12 +83,20 @@ _applyEnv(var v, Map<String, String> env) {
 }
 
 /// Dynamically loads application configuration from configuration files.
+///
+/// You can modify which [directoryPath] to search in, or explicitly
+/// load from a [overrideEnvironmentName].
+///
+/// You can also specify a custom [envPath] to load system configuration from.
 AngelConfigurer loadConfigurationFile(
-    {String directoryPath: "./config", String overrideEnvironmentName}) {
+    {String directoryPath: "./config",
+    String overrideEnvironmentName,
+    String envPath}) {
   return (Angel app) async {
     Directory sourceDirectory = new Directory(directoryPath);
     var env = dotenv.env;
-    var envFile = new File.fromUri(sourceDirectory.uri.resolve('.env'));
+    var envFile =
+        new File.fromUri(sourceDirectory.uri.resolve(envPath ?? '.env'));
 
     if (await envFile.exists()) {
       try {
diff --git a/pubspec.yaml b/pubspec.yaml
index d46edc7f..1e5a975c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,14 +1,16 @@
 name: angel_configuration
 description: Automatic YAML configuration loader for Angel.
-version: 1.0.4
+version: 1.0.5
 author: Tobe O <thosakwe@gmail.com>
 homepage: https://github.com/angel-dart/angel_configuration
+environment:
+  sdk: ">=1.19.0"
 dependencies:
   analyzer: ">=0.28.1 <1.0.0"
-  angel_framework: ">=1.0.0-dev < 2.0.0"
-  angel_route: ">=1.0.0-dev < 2.0.0"
-  barback: ">=0.15.2 < 0.16.0"
-  dotenv: ">=0.1.3 <0.2.0"
-  yaml: ">= 2.1.8 < 2.2.0"
+  angel_framework: ^1.0.0-dev
+  barback: ^0.15.2
+  dotenv: ^0.1.0
+  merge_map: ^1.0.0
+  yaml: ^2.0.0
 dev_dependencies:
-  test: ">= 0.12.13 < 0.13.0"
+  test: ^0.12.0
diff --git a/test/all_test.dart b/test/all_test.dart
index cdef5909..5fa3c816 100644
--- a/test/all_test.dart
+++ b/test/all_test.dart
@@ -6,8 +6,7 @@ import 'transformer.dart' as transformer;
 main() async {
   // Note: Set ANGEL_ENV to 'development'
   var app = new Angel();
-  await app.configure(
-      loadConfigurationFile(directoryPath: './test/config'));
+  await app.configure(loadConfigurationFile(directoryPath: './test/config'));
 
   test('can load based on ANGEL_ENV', () async {
     expect(app.properties['hello'], equals('world'));
@@ -35,7 +34,11 @@ main() async {
     expect(app.properties['foo']['version'], equals('baz'));
   });
 
-
+  test('merges configuration', () async {
+    await app.configure(loadConfigurationFile(
+        directoryPath: './test/config', overrideEnvironmentName: 'override'));
+    expect(app.properties['merge'], {'map': true, 'hello': 'goodbye'});
+  });
 
   group("transformer", transformer.main);
 }
diff --git a/test/config/default.yaml b/test/config/default.yaml
index 11f67070..2a7d3954 100644
--- a/test/config/default.yaml
+++ b/test/config/default.yaml
@@ -2,4 +2,7 @@ set_via: default
 artist: $JUSTIN
 angel:
   framework: $ANGEL_FRAMEWORK
-must_be_null: $NONEXISTENT_KEY_FOO_BAR_BAZ_QUUX
\ No newline at end of file
+must_be_null: $NONEXISTENT_KEY_FOO_BAR_BAZ_QUUX
+merge:
+  map: true
+  hello: world
\ No newline at end of file
diff --git a/test/config/override.yaml b/test/config/override.yaml
index e0ac5ffa..fb07c149 100644
--- a/test/config/override.yaml
+++ b/test/config/override.yaml
@@ -1,3 +1,5 @@
 hello: goodbye
 foo:
-  version: baz
\ No newline at end of file
+  version: baz
+merge:
+  hello: goodbye
\ No newline at end of file