diff --git a/dist/index.js b/dist/index.js
index 88b0893..642d565 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -15,17 +15,45 @@ let device_service = new Device.Service();
 var router = express.Router();
 router.post("/signup", (req, res) => {
     let user = { username: req.body.username, password: req.body.password };
-    user_service.signup(user).then(() => res.json(true)).catch(() => res.json(false));
+    user_service.signup(user).then(() => res.json({ success: user.username })).catch((reason) => res.json({ error: reason }));
 });
 router.post('/login', function (req, res) {
-    res.json({ token: 'youmadeit' });
+    return user_service.login(req.body.username, req.body.password).then(user => {
+        let token = session_service.acquire(user.username);
+        res.json({ token: token });
+    })
+        .catch(reason => res.json({ error: reason }));
+});
+router.post("/lost-password", function (req, res) {
+    res.json({ success: "An email will be sent to your address." });
 });
 router.get('/switch', function (req, res) {
-    res.json({ status: switch_status });
+    session_service.retrieve(req.query.token).then(user => res.json({ status: switch_status }))
+        .catch(reason => res.json({ error: reason }));
 });
 router.post('/switch', function (req, res) {
-    switch_status = req.body.status;
-    res.json({ status: switch_status });
+    session_service.retrieve(req.query.token).then(user => {
+        switch_status = req.body.status;
+        res.json({ status: switch_status });
+    })
+        .catch(reason => res.json({ error: reason }));
+});
+router.post("/history", function (req, res) {
+    session_service.retrieve(req.query.token).then(user => {
+        res.json({ user: user,
+            history: [
+                { date: new Date(2016, 8, 1, 10, 10), status: { switch: true, presence: true } },
+                { date: new Date(2016, 8, 1, 10, 16), status: { switch: true, presence: true } },
+                { date: new Date(2016, 8, 1, 10, 30), status: { switch: false, presence: false } },
+                { date: new Date(2016, 8, 1, 11, 10), status: { switch: false, presence: false } },
+                { date: new Date(2016, 8, 1, 11, 16), status: { switch: true, presence: false } },
+                { date: new Date(2016, 8, 1, 15, 22), status: { switch: true, presence: true } },
+                { date: new Date(2016, 8, 1, 15, 30), status: { switch: true, presence: true } },
+                { date: new Date(2016, 8, 1, 15, 35), status: { switch: false, presence: true } },
+                { date: new Date(2016, 8, 1, 15, 55), status: { switch: true, presence: true } },
+            ] });
+    })
+        .catch(reason => res.json({ error: reason }));
 });
 app.use('/', router);
 app.listen(port);
diff --git a/dist/models/user.js b/dist/models/user.js
new file mode 100644
index 0000000..8ecbace
--- /dev/null
+++ b/dist/models/user.js
@@ -0,0 +1,5 @@
+"use strict";
+class Model {
+}
+exports.Model = Model;
+;
diff --git a/dist/services/session.js b/dist/services/session.js
index f15ddf9..d07ad5b 100644
--- a/dist/services/session.js
+++ b/dist/services/session.js
@@ -1,5 +1,33 @@
 "use strict";
+const Datastore = require("nedb");
+const shortid = require("shortid");
+class Token {
+}
+exports.Token = Token;
+;
 class Service {
+    constructor() {
+        this.db = new Datastore({ filename: "./sessions.db", autoload: true });
+    }
+    acquire(username) {
+        let token = new Token();
+        token.__id = shortid.generate();
+        token.username = username;
+        this.db.insert(token);
+        return token.__id;
+    }
+    retrieve(token) {
+        return new Promise((resolve, reject) => {
+            this.db.findOne({ __id: token }, (err, document) => {
+                if (err)
+                    return reject(err.message);
+                if (document) {
+                    return resolve(document.username);
+                }
+                return reject("Token not found.");
+            });
+        });
+    }
 }
 exports.Service = Service;
 ;
diff --git a/dist/services/user.js b/dist/services/user.js
index cfa120c..87b3916 100644
--- a/dist/services/user.js
+++ b/dist/services/user.js
@@ -1,31 +1,38 @@
 "use strict";
 const Datastore = require("nedb");
-class Model {
-}
-exports.Model = Model;
-;
 class Service {
     constructor() {
         this.db = new Datastore({ filename: "./users.db", autoload: true });
     }
     signup(user) {
-        return new Promise((resolve, reject) => this.db.insert(user, (err, document) => {
-            if (err) {
-                return reject(err);
-            }
-            return resolve();
-        }));
+        return new Promise((resolve, reject) => {
+            this.db.findOne({ username: user.username }, (err, doc) => {
+                if (err)
+                    return reject(err);
+                if (doc) {
+                    return reject("The user already exists.");
+                }
+                this.db.insert(user, (err, document) => {
+                    if (err) {
+                        return reject(err.message);
+                    }
+                    return resolve(true);
+                });
+            });
+        });
     }
-    ;
     login(username, password) {
         return new Promise((resolve, reject) => this.db.findOne({
             username: username, password: password
         }, (err, document) => {
             if (err) {
-                return reject(err);
+                return reject(err.message);
             }
             else {
-                return resolve(document);
+                if (document) {
+                    return resolve(document);
+                }
+                return reject("Not found.");
             }
         }));
     }
diff --git a/package.json b/package.json
index 3a0f172..fbcc24b 100644
--- a/package.json
+++ b/package.json
@@ -24,7 +24,8 @@
   "dependencies": {
     "body-parser": "^1.15.2",
     "express": "^4.14.0",
-    "nedb": "^1.8.0"
+    "nedb": "^1.8.0",
+    "shortid": "^2.2.6"
   },
   "devDependencies": {
     "gulp": "^3.9.1",
diff --git a/sessions.db b/sessions.db
new file mode 100644
index 0000000..3174968
--- /dev/null
+++ b/sessions.db
@@ -0,0 +1,3 @@
+{"__id":"HkZEj0-j","username":"ignacio","_id":"Iey1FPz1W2a26EJT"}
+{"__id":"SkWp9Cbi","username":"ignacio","_id":"uL5rllhEIEVAIjyn"}
+{"__id":"B1d8GyGj","username":"ignacio","_id":"TprKNb94X88OnZSQ"}
diff --git a/src/index.ts b/src/index.ts
index e4a8563..2945fcb 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,6 +3,8 @@
 import express = require("express");
 import bodyParser = require("body-parser");
 
+import * as UserModel from "./models/user";
+
 import * as Device from "./services/device";
 import * as User from "./services/user";
 import * as Session from "./services/session";
@@ -22,18 +24,47 @@ let device_service = new Device.Service();
 
 var router = express.Router();
 router.post("/signup", (req,res) => {
-    let user: User.Model = { username: req.body.username, password: req.body.password };
-    user_service.signup(user).then(() => res.json(true)).catch(() => res.json(false));
+    let user: UserModel.Model = { username: req.body.username, password: req.body.password };
+    user_service.signup(user).then(() => res.json({success: user.username})).catch((reason) => res.json({error: reason}));
 });
 router.post('/login', function(req, res) {
-    res.json({ token: 'youmadeit' });
+    return user_service.login(req.body.username, req.body.password).then(user => 
+    {
+        let token = session_service.acquire(user.username);
+        res.json({ token: token });
+    })
+    .catch(reason => res.json({ error: reason }));
+});
+router.post("/lost-password", function(req,res) {
+    res.json({success: "An email will be sent to your address."});
 });
 router.get('/switch', function(req, res) {
-    res.json({ status: switch_status });   
+    session_service.retrieve(req.query.token).then(user => res.json({ status: switch_status }))
+    .catch(reason => res.json({error: reason}));
 });
 router.post('/switch', function(req, res) {
-    switch_status = req.body.status;
-    res.json({ status: switch_status });   
+    session_service.retrieve(req.query.token).then(user => {
+        switch_status = req.body.status;
+        res.json({ status: switch_status });   
+    })
+    .catch(reason => res.json({error: reason}));
+});
+router.post("/history", function(req,res) {
+    session_service.retrieve(req.query.token).then(user => {
+        res.json({user: user,
+            history: [
+            { date: new Date(2016,8,1,10,10), status: {switch: true, presence: true} },
+            { date: new Date(2016,8,1,10,16), status: {switch: true, presence: true} },
+            { date: new Date(2016,8,1,10,30), status: {switch: false, presence: false} },
+            { date: new Date(2016,8,1,11,10), status: {switch: false, presence: false} },
+            { date: new Date(2016,8,1,11,16), status: {switch: true, presence: false} },
+            { date: new Date(2016,8,1,15,22), status: {switch: true, presence: true} },
+            { date: new Date(2016,8,1,15,30), status: {switch: true, presence: true} },
+            { date: new Date(2016,8,1,15,35), status: {switch: false, presence: true} },
+            { date: new Date(2016,8,1,15,55), status: {switch: true, presence: true} },
+            ]});
+    })
+    .catch(reason => res.json({error: reason}));
 });
 
 app.use('/', router);
diff --git a/src/models/user.ts b/src/models/user.ts
new file mode 100644
index 0000000..d10ae00
--- /dev/null
+++ b/src/models/user.ts
@@ -0,0 +1,4 @@
+export class Model {
+    username: string;
+    password: string;
+};
diff --git a/src/services/session.ts b/src/services/session.ts
index 5487723..a4f2e84 100644
--- a/src/services/session.ts
+++ b/src/services/session.ts
@@ -1,3 +1,34 @@
+import Datastore = require("nedb");
+import shortid = require("shortid");
+
+export class Token {
+    __id        : string;
+    username    : string;
+    expiration  : Date;
+};
+
 export class Service {
-    
+    db: Datastore;
+    constructor() {
+        this.db = new Datastore({filename: "./sessions.db", autoload: true});
+    }
+    acquire(username: string): string {
+        let token = new Token();
+        token.__id = shortid.generate();
+        token.username = username;
+        this.db.insert(token);
+        return token.__id;
+    }
+    retrieve(token: string): Promise<string> {
+        return new Promise((resolve,reject) => {
+            this.db.findOne({__id: token}, (err,document: Token) => {
+                if (err)
+                    return reject(err.message);
+                if (document) {
+                    return resolve(document.username);
+                }
+                return reject("Token not found.");
+            });
+        });
+    }
 };
diff --git a/src/services/user.ts b/src/services/user.ts
index f7c54ed..789c4d3 100644
--- a/src/services/user.ts
+++ b/src/services/user.ts
@@ -1,32 +1,40 @@
 import Datastore = require("nedb");
-
-export class Model {
-    username: string;
-    password: string;
-};
+import * as UserModel from "../models/user";
 
 export class Service {
     db: Datastore;
     constructor() {
         this.db = new Datastore({filename: "./users.db", autoload: true});
     }
-    signup(user: Model): Promise<any> {
-        return new Promise((resolve,reject) => this.db.insert(user, (err,document) => {
-            if (err) {
-                return reject(err);
-            }
-            return resolve();
-        }));
-    };
-    login(username: string, password: string): Promise<Model> {
-        return new Promise<Model>((resolve,reject) => this.db.findOne({
+    signup(user: UserModel.Model): Promise<any> {
+        return new Promise((resolve,reject) => {
+                this.db.findOne({username: user.username}, (err,doc) => {
+                    if (err) return reject(err);
+                    if (doc) {
+                        return reject("The user already exists.");
+                    }
+                    this.db.insert(user, (err,document) => {
+                        if (err) {
+                            return reject(err.message);
+                        }
+                        return resolve(true);
+                    }
+                );
+            });
+        });
+    }
+    login(username: string, password: string): Promise<UserModel.Model> {
+        return new Promise<UserModel.Model>((resolve,reject) => this.db.findOne({
             username: username, password: password
         }, (err,document) => {
             if (err) {
-                return reject(err);
+                return reject(err.message);
             }
             else {
-                return resolve(document as Model);
+                if (document) {
+                    return resolve(document as UserModel.Model);
+                }
+                return reject("Not found.");
             }
         }));
     };
diff --git a/typings.json b/typings.json
index d674ba4..734ffa4 100644
--- a/typings.json
+++ b/typings.json
@@ -4,6 +4,7 @@
     "es6-promise": "registry:npm/es6-promise#3.0.0+20160723033700"
   },
   "globalDependencies": {
-    "nedb": "registry:dt/nedb#0.0.0+20160505185910"
+    "nedb": "registry:dt/nedb#0.0.0+20160505185910",
+    "shortid": "registry:dt/shortid#0.0.0+20160316155526"
   }
 }
diff --git a/typings/globals/shortid/index.d.ts b/typings/globals/shortid/index.d.ts
new file mode 100644
index 0000000..529e95a
--- /dev/null
+++ b/typings/globals/shortid/index.d.ts
@@ -0,0 +1,9 @@
+// Generated by typings
+// Source: https://raw.githubusercontent.com/DefinitelyTyped/DefinitelyTyped/56295f5058cac7ae458540423c50ac2dcf9fc711/shortid/shortid.d.ts
+declare module "shortid" {
+	export function generate(): string;
+	export function characters(string: string): string;
+	export function isValid(id: any): boolean;
+	export function worker(integer: number): void;
+	export function seed(float: number): void;
+}
diff --git a/typings/globals/shortid/typings.json b/typings/globals/shortid/typings.json
new file mode 100644
index 0000000..29c1a66
--- /dev/null
+++ b/typings/globals/shortid/typings.json
@@ -0,0 +1,8 @@
+{
+  "resolution": "main",
+  "tree": {
+    "src": "https://raw.githubusercontent.com/DefinitelyTyped/DefinitelyTyped/56295f5058cac7ae458540423c50ac2dcf9fc711/shortid/shortid.d.ts",
+    "raw": "registry:dt/shortid#0.0.0+20160316155526",
+    "typings": "https://raw.githubusercontent.com/DefinitelyTyped/DefinitelyTyped/56295f5058cac7ae458540423c50ac2dcf9fc711/shortid/shortid.d.ts"
+  }
+}
diff --git a/typings/index.d.ts b/typings/index.d.ts
index 47243db..d977a67 100644
--- a/typings/index.d.ts
+++ b/typings/index.d.ts
@@ -1,5 +1,6 @@
 /// <reference path="globals/nedb/index.d.ts" />
 /// <reference path="globals/node/index.d.ts" />
+/// <reference path="globals/shortid/index.d.ts" />
 /// <reference path="modules/body-parser/index.d.ts" />
 /// <reference path="modules/es6-promise/index.d.ts" />
 /// <reference path="modules/express/index.d.ts" />
diff --git a/users.db b/users.db
new file mode 100644
index 0000000..86bee47
--- /dev/null
+++ b/users.db
@@ -0,0 +1,15 @@
+{"_id":"1c966sQXzKWWPAyf"}
+{"_id":"3u7L6W7f3zPV9yMb"}
+{"username":"nicolas","password":"test123","_id":"A0hn3PZxux1OIyc5"}
+{"_id":"B973eCDaoOyKL1A1"}
+{"_id":"C7zA558rKbDUgXXU"}
+{"_id":"CAPhGDJiwkmwKNl3"}
+{"_id":"G5FNaevxTEcMH2y7"}
+{"_id":"KCbkAzouj49JHIBn"}
+{"_id":"MqWTHG88N6MtHqyg"}
+{"_id":"O1Gv1VYFCVbxhwOk"}
+{"_id":"QR7QVpxnn9vf3wHP"}
+{"username":"ignacio","password":"test123","_id":"XhvPJQWc2w026Xzv"}
+{"password":"test123","_id":"cEcFIaxF4iYlQxc6"}
+{"_id":"d5AjbtdZz3nWvOl0"}
+{"_id":"gWH2ZAKqMkz4vu37"}