diff --git a/lib/helpers/account_credentials_helper.dart b/lib/helpers/account_credentials_helper.dart
index 04d552b..3c3409f 100644
--- a/lib/helpers/account_credentials_helper.dart
+++ b/lib/helpers/account_credentials_helper.dart
@@ -1,3 +1,8 @@
+import 'dart:convert';
+
+import 'package:comunic/models/login_tokens.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
 /// Accounts credentials helper
 ///
 /// Stores current account tokens
@@ -8,7 +13,27 @@ class AccountCredentialsHelper {
 
   /// Checkout whether current user is signed in or not
   Future<bool> signedIn() async {
-    return false; // TODO : implement
+    return await get() != null;
   }
 
+  /// Set new login tokens
+  Future<void> set(LoginTokens tokens) async {
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    await prefs.setString("login_tokens", tokens.toString());
+  }
+
+  /// Get current [LoginTokens]. Returns null if none or in case of failure
+  Future<LoginTokens> get() async {
+    try {
+
+      SharedPreferences prefs = await SharedPreferences.getInstance();
+      final string = prefs.getString("login_tokens");
+      if(string == null) return null;
+      return LoginTokens.fromJSON(jsonDecode(string));
+
+    } on Exception catch(e){
+      print(e.toString());
+      return null;
+    }
+  }
 }
\ No newline at end of file
diff --git a/lib/helpers/account_helper.dart b/lib/helpers/account_helper.dart
new file mode 100644
index 0000000..f4873ff
--- /dev/null
+++ b/lib/helpers/account_helper.dart
@@ -0,0 +1,41 @@
+import 'package:comunic/helpers/account_credentials_helper.dart';
+import 'package:comunic/helpers/api_helper.dart';
+import 'package:comunic/models/api_request.dart';
+import 'package:comunic/models/authentication_details.dart';
+import 'package:comunic/models/login_tokens.dart';
+
+/// Account helper
+///
+/// @author Pierre HUBERT
+
+enum AuthResult {
+  SUCCESS,
+  TOO_MANY_ATTEMPTS,
+  NETWORK_ERROR,
+  INVALID_CREDENTIALS
+}
+
+class AccountHelper {
+  /// Sign in user
+  Future<AuthResult> signIn(AuthenticationDetails auth) async {
+    final request = APIRequest(uri: "account/login");
+    request.addString("userMail", auth.email);
+    request.addString("userPassword", auth.password);
+
+    final response = await APIHelper().exec(request);
+
+    // Handle errors
+    if (response.code == 401)
+      return AuthResult.INVALID_CREDENTIALS;
+    else if (response.code == 429)
+      return AuthResult.TOO_MANY_ATTEMPTS;
+    else if (response.code != 200) return AuthResult.NETWORK_ERROR;
+
+    //Save login tokens
+    final tokensObj = response.getObject()["tokens"];
+    await AccountCredentialsHelper()
+        .set(LoginTokens(tokensObj["token1"], tokensObj["token2"]));
+
+    return AuthResult.SUCCESS;
+  }
+}
diff --git a/lib/helpers/api_helper.dart b/lib/helpers/api_helper.dart
new file mode 100644
index 0000000..2f486b2
--- /dev/null
+++ b/lib/helpers/api_helper.dart
@@ -0,0 +1,68 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:comunic/models/api_request.dart';
+import 'package:comunic/models/api_response.dart';
+import 'package:comunic/models/config.dart';
+
+/// API Helper
+///
+/// @author Pierre HUBERT
+
+class APIHelper {
+  final _httpClient = HttpClient();
+
+  /// Execute a [request] on the server and returns a [APIResponse]
+  ///
+  /// This method should never throw but the response code of the [APIResponse]
+  /// should be verified before accessing response content
+  Future<APIResponse> exec(APIRequest request) async {
+    try {
+      //Add API tokens
+      request.addString("serviceName", config().serviceName);
+      request.addString("serviceToken", config().serviceToken);
+
+      //Add user tokens (if required)
+      if (request.needLogin) throw "Can add user tokens right now !";
+
+      // Prepare request body
+      String requestBody = "";
+      request.args.forEach((key, value) => requestBody +=
+          Uri.encodeQueryComponent(key) +
+              "=" +
+              Uri.encodeQueryComponent(value) +
+              "&");
+
+      List<int> bodyBytes = utf8.encode(requestBody);
+
+      // Determine server URL
+      final path = config().apiServerUri + request.uri;
+      Uri url;
+      if (!config().apiServerSecure)
+        url = Uri.http(config().apiServerName, path);
+      else
+        url = Uri.https(config().apiServerName, path);
+
+      //Connect to server
+      final connection = await _httpClient.postUrl(url);
+      connection.headers.set("Content-Length", bodyBytes.length.toString());
+      connection.headers
+          .set("Content-Type", "application/x-www-form-urlencoded");
+      connection.add(bodyBytes);
+
+      final response = await connection.close();
+
+      if (response.statusCode != HttpStatus.ok)
+        return APIResponse(response.statusCode, null);
+
+      //Save & return response
+      final responseBody = await response.transform(utf8.decoder).join();
+
+      return APIResponse(response.statusCode, responseBody);
+    } on Exception catch (e) {
+      print(e.toString());
+      print("Could not execute a request!");
+      return APIResponse(-1, null);
+    }
+  }
+}
diff --git a/lib/main.dart b/lib/main.dart
index 122dbcc..ad8700f 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -1,5 +1,8 @@
 import 'package:comunic/helpers/account_credentials_helper.dart';
-import 'package:comunic/ui/login_route.dart';
+import 'package:comunic/models/config.dart';
+import 'package:comunic/ui/routes/home_route.dart';
+import 'package:comunic/ui/routes/login_route.dart';
+import 'package:comunic/utils/ui_utils.dart';
 import 'package:flutter/material.dart';
 
 /// Main file of the application
@@ -7,6 +10,16 @@ import 'package:flutter/material.dart';
 /// @author Pierre HUBERT
 
 void main() {
+  /// Initialize application configuration
+  ///
+  // TODO : Adapt to production
+  Config.set(Config(
+      apiServerName: "devweb.local",
+      apiServerUri: "/comunic/api/",
+      apiServerSecure: false,
+      serviceName: "ComunicFlutter",
+      serviceToken: "G9sZCBmb3IgVWJ1bnR1CkNvbW1lbnRbbmVdPeCkieCkrOCkq"));
+
   runApp(ComunicApplication());
 }
 
@@ -15,20 +28,37 @@ class ComunicApplication extends StatelessWidget {
   Widget build(BuildContext context) {
     return MaterialApp(
       debugShowCheckedModeBanner: false,
-      // We need to know whether the user is signed in or not to continue
-      home: FutureBuilder(
-        future: AccountCredentialsHelper().signedIn(),
-        builder: (b, AsyncSnapshot<bool> c){
-          if(!c.hasData)
-            return CircularProgressIndicator();
-
-          else
-            if(c.data)
-              throw "Not supported yet !";
-            else
-              return LoginRoute();
-        },
-      ),
+      home: ComunicApplicationHome(),
     );
   }
 }
+
+class ComunicApplicationHome extends StatefulWidget {
+  @override
+  State<StatefulWidget> createState() => _ComunicApplicationHomeState();
+}
+
+class _ComunicApplicationHomeState extends State<ComunicApplicationHome> {
+  bool _signedIn;
+
+  @override
+  void initState() {
+    super.initState();
+
+    AccountCredentialsHelper().signedIn().then((v) {
+      setState(() {
+        _signedIn = v;
+      });
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    if (_signedIn == null) return buildLoadingPage();
+
+    if (_signedIn)
+      return HomeRoute();
+    else
+      return LoginRoute();
+  }
+}
diff --git a/lib/models/api_request.dart b/lib/models/api_request.dart
new file mode 100644
index 0000000..9ae2e74
--- /dev/null
+++ b/lib/models/api_request.dart
@@ -0,0 +1,27 @@
+import 'package:meta/meta.dart';
+
+/// API Request model
+///
+/// Contains all the information associated to an API request
+///
+/// @author Pierre HUBERT
+
+class APIRequest {
+  final String uri;
+  final bool needLogin;
+  Map<String, String> args;
+
+  APIRequest({
+    @required this.uri,
+    this.needLogin = false,
+  })  : assert(uri != null),
+        assert(needLogin != null),
+        args = Map();
+
+  void addString(String name, String value) => args[name] = value;
+
+  void addInt(String name, int value) => args[name] = value.toString();
+
+  void addBool(String name, bool value) =>
+      args[name] = value ? "true" : "false";
+}
diff --git a/lib/models/api_response.dart b/lib/models/api_response.dart
new file mode 100644
index 0000000..227f207
--- /dev/null
+++ b/lib/models/api_response.dart
@@ -0,0 +1,16 @@
+import 'dart:convert';
+
+/// API response
+///
+/// @author Pierre HUBERT
+
+class APIResponse {
+  final int code;
+  final String content;
+
+  const APIResponse(this.code, this.content) : assert(code != null);
+
+  List<dynamic> getArray() => jsonDecode(this.content);
+
+  Map<String, dynamic> getObject() => jsonDecode(this.content);
+}
diff --git a/lib/models/authentication_details.dart b/lib/models/authentication_details.dart
new file mode 100644
index 0000000..5d38dc2
--- /dev/null
+++ b/lib/models/authentication_details.dart
@@ -0,0 +1,14 @@
+import 'package:meta/meta.dart';
+
+/// Authentication details
+///
+/// @author Pierre HUBERT
+
+class AuthenticationDetails {
+  final String email;
+  final String password;
+
+  const AuthenticationDetails({@required this.email, @required this.password})
+      : assert(email != null),
+        assert(password != null);
+}
diff --git a/lib/models/config.dart b/lib/models/config.dart
new file mode 100644
index 0000000..249468b
--- /dev/null
+++ b/lib/models/config.dart
@@ -0,0 +1,42 @@
+import 'package:meta/meta.dart';
+
+/// Application configuration model
+///
+/// @author Pierre HUBERT
+
+/// Configuration class
+class Config {
+  final String apiServerName;
+  final String apiServerUri;
+  final bool apiServerSecure;
+  final String serviceName;
+  final String serviceToken;
+
+  const Config(
+      {@required this.apiServerName,
+      @required this.apiServerUri,
+      @required this.apiServerSecure,
+      @required this.serviceName,
+      @required this.serviceToken})
+      : assert(apiServerName != null),
+        assert(apiServerUri != null),
+        assert(apiServerSecure != null),
+        assert(serviceName != null),
+        assert(serviceToken != null);
+
+  /// Get and set static configuration
+  static Config _config;
+
+  static Config get() {
+    return _config;
+  }
+
+  static void set(Config conf) {
+    _config = conf;
+  }
+}
+
+/// Get the current configuration of the application
+Config config() {
+  return Config.get();
+}
diff --git a/lib/models/login_tokens.dart b/lib/models/login_tokens.dart
new file mode 100644
index 0000000..67cc5e0
--- /dev/null
+++ b/lib/models/login_tokens.dart
@@ -0,0 +1,23 @@
+import 'dart:convert';
+
+/// Login tokens model
+///
+/// @author Pierre HUBERT
+
+class LoginTokens {
+  final String tokenOne;
+  final String tokenTwo;
+
+  const LoginTokens(this.tokenOne, this.tokenTwo)
+      : assert(tokenOne != null),
+        assert(tokenTwo != null);
+
+  LoginTokens.fromJSON(Map<String, dynamic> json)
+      : tokenOne = json["token_one"],
+        tokenTwo = json["token_two"];
+
+  @override
+  String toString() {
+    return jsonEncode({"token_one": tokenOne, "token_two": tokenTwo});
+  }
+}
diff --git a/lib/ui/routes/home_route.dart b/lib/ui/routes/home_route.dart
new file mode 100644
index 0000000..0ac6b96
--- /dev/null
+++ b/lib/ui/routes/home_route.dart
@@ -0,0 +1,12 @@
+import 'package:flutter/material.dart';
+
+/// Main route of the application
+///
+/// @author Pierre HUBERT
+
+class HomeRoute extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Text("Home route");
+  }
+}
\ No newline at end of file
diff --git a/lib/ui/login_route.dart b/lib/ui/routes/login_route.dart
similarity index 56%
rename from lib/ui/login_route.dart
rename to lib/ui/routes/login_route.dart
index 30f98e2..7e4bce5 100644
--- a/lib/ui/login_route.dart
+++ b/lib/ui/routes/login_route.dart
@@ -1,5 +1,9 @@
+import 'package:comunic/helpers/account_helper.dart';
+import 'package:comunic/models/authentication_details.dart';
+import 'package:comunic/ui/routes/home_route.dart';
 import 'package:comunic/utils/input_utils.dart';
 import 'package:comunic/utils/intl_utils.dart';
+import 'package:comunic/utils/ui_utils.dart';
 import 'package:flutter/material.dart';
 
 /// Login route
@@ -14,6 +18,7 @@ class LoginRoute extends StatefulWidget {
 class _LoginRouteState extends State<LoginRoute> {
   String _currEmail;
   String _currPassword;
+  AuthResult _authResult;
 
   @override
   void initState() {
@@ -35,26 +40,51 @@ class _LoginRouteState extends State<LoginRoute> {
   }
 
   /// Call this whenever the user request to perform login
-  void _submitForm() {
+  Future<void> _submitForm(BuildContext context) async {
+    final loginResult = await AccountHelper().signIn(
+        AuthenticationDetails(email: _currEmail, password: _currPassword));
 
+    if (loginResult == AuthResult.SUCCESS)
+      Navigator.pushReplacement(
+          context, MaterialPageRoute(builder: (b) => HomeRoute()));
+    else
+      setState(() {
+        _authResult = loginResult;
+      });
+  }
+
+  // Build error card
+  Widget _buildErrorCard() {
+    if (_authResult == null)
+      return null;
+
+    //Determine the right message
+    final message = (_authResult == AuthResult.INVALID_CREDENTIALS ? tr(
+        "Invalid credentials!") : (_authResult == AuthResult.TOO_MANY_ATTEMPTS
+        ? tr("Too many unsuccessfull login attempts! Please try again later...")
+        : tr("A network error occured!")));
+
+    return buildErrorCard(message);
   }
 
   /// Build login form
-  Widget _buildLoginForm(){
+  Widget _buildLoginForm() {
     return SingleChildScrollView(
       child: Padding(
         padding: const EdgeInsets.all(8.0),
         child: Column(
           children: <Widget>[
             Text(tr("Please sign into your Comunic account: ")),
+            Container(
+              child: _buildErrorCard(),
+            ),
             //Email address
             TextField(
               keyboardType: TextInputType.emailAddress,
               decoration: InputDecoration(
                   labelText: tr("Email address"),
                   alignLabelWithHint: true,
-                  errorText:
-                  _currEmail.length > 0 && !validateEmail(_currEmail)
+                  errorText: _currEmail.length > 0 && !validateEmail(_currEmail)
                       ? tr("Invalid email address!")
                       : null),
               onChanged: _emailChanged,
@@ -72,7 +102,9 @@ class _LoginRouteState extends State<LoginRoute> {
 
             RaisedButton(
               child: Text(tr("Sign in")),
-              onPressed: !validateEmail(_currEmail) || _currPassword.length < 3 ? null : _submitForm,
+              onPressed: !validateEmail(_currEmail) || _currPassword.length < 3
+                  ? null
+                  : () => _submitForm(context),
             )
           ],
         ),
@@ -83,10 +115,9 @@ class _LoginRouteState extends State<LoginRoute> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(
-        title: Text("Comunic"),
-      ),
-      body: _buildLoginForm()
-    );
+        appBar: AppBar(
+          title: Text("Comunic"),
+        ),
+        body: _buildLoginForm());
   }
 }
diff --git a/lib/utils/ui_utils.dart b/lib/utils/ui_utils.dart
new file mode 100644
index 0000000..db8b13d
--- /dev/null
+++ b/lib/utils/ui_utils.dart
@@ -0,0 +1,41 @@
+import 'package:flutter/material.dart';
+
+/// User interface utilities
+
+/// Build and return a full loading page
+Widget buildLoadingPage() {
+  return Scaffold(
+    body: Center(
+      child: CircularProgressIndicator(),
+    ),
+  );
+}
+
+/// Build and return an error card
+Widget buildErrorCard(String message) {
+  return Card(
+    elevation: 2.0,
+    color: Colors.red,
+    child: Padding(
+      padding: const EdgeInsets.all(8.0),
+      child: Row(
+        children: <Widget>[
+          Padding(
+            padding: const EdgeInsets.only(right: 8.0),
+            child: Icon(
+              Icons.error,
+              color: Colors.white,
+            ),
+          ),
+          Flexible(
+            child: Text(
+              message,
+              style: TextStyle(color: Colors.white),
+              maxLines: null,
+            ),
+          )
+        ],
+      ),
+    ),
+  );
+}
diff --git a/pubspec.lock b/pubspec.lock
index 795d74c..5cc348c 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -81,6 +81,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.1"
+  shared_preferences:
+    dependency: "direct main"
+    description:
+      name: shared_preferences
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.5.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -144,3 +151,4 @@ packages:
     version: "2.0.8"
 sdks:
   dart: ">=2.1.0 <3.0.0"
+  flutter: ">=0.1.4 <2.0.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index 77fcdbd..76cc0d4 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -24,6 +24,9 @@ dependencies:
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^0.1.2
 
+  # Preferences are useful for a lot of things (ex: login tokens)
+  shared_preferences: ^0.5.2
+
 dev_dependencies:
   flutter_test:
     sdk: flutter