diff --git a/build.gradle.kts b/build.gradle.kts
index 47774a6..674d0a0 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -16,7 +16,6 @@ version = "1.0"
 
 application {
     mainClass.set("es.wokis.ApplicationKt")
-    mainClassName = "es.wokis.ApplicationKt"
 
     val isDevelopment: Boolean = project.ext.has("development")
     applicationDefaultJvmArgs = listOf("-Dio.ktor.development=$isDevelopment")
@@ -55,6 +54,13 @@ dependencies {
 
     // BCrypt
     implementation("org.mindrot:jbcrypt:0.4")
+
+    // Google auth
+    implementation("com.google.api-client:google-api-client:2.1.1")
+
+    // JavaMail
+    implementation("javax.mail:javax.mail-api:1.6.2")
+    implementation("com.sun.mail:javax.mail:1.6.2")
 }
 
 ktor {
diff --git a/gradle.properties b/gradle.properties
index 6598b14..4b31c03 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,4 +1,4 @@
-ktor_version=2.1.3
+ktor_version=2.2.1
 kotlin_version=1.7.21
 logback_version=1.4.4
 kmongo_version=4.7.2
diff --git a/src/main/kotlin/es/wokis/data/bo/user/UserBO.kt b/src/main/kotlin/es/wokis/data/bo/user/UserBO.kt
index 6e65099..67905f3 100644
--- a/src/main/kotlin/es/wokis/data/bo/user/UserBO.kt
+++ b/src/main/kotlin/es/wokis/data/bo/user/UserBO.kt
@@ -1,5 +1,6 @@
 package es.wokis.data.bo.user
 
+import es.wokis.data.constants.ServerConstants.DEFAULT_LANG
 import es.wokis.data.constants.ServerConstants.EMPTY_TEXT
 import io.ktor.server.auth.*
 
@@ -9,5 +10,6 @@ data class UserBO(
     val email: String,
     val password: String,
     val image: String = EMPTY_TEXT,
+    val lang: String = DEFAULT_LANG,
     val devices: List<String> = emptyList()
 ) : Principal
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/bo/verification/VerificationBO.kt b/src/main/kotlin/es/wokis/data/bo/verification/VerificationBO.kt
new file mode 100644
index 0000000..a521127
--- /dev/null
+++ b/src/main/kotlin/es/wokis/data/bo/verification/VerificationBO.kt
@@ -0,0 +1,10 @@
+package es.wokis.data.bo.verification
+
+import java.util.*
+
+data class VerificationBO(
+    val id: Long? = null,
+    val email: String,
+    val verificationToken: String,
+    val timeStamp: Date = Date()
+)
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/constants/ServerConstants.kt b/src/main/kotlin/es/wokis/data/constants/ServerConstants.kt
index 8d5bd23..8dd4254 100644
--- a/src/main/kotlin/es/wokis/data/constants/ServerConstants.kt
+++ b/src/main/kotlin/es/wokis/data/constants/ServerConstants.kt
@@ -2,4 +2,5 @@ package es.wokis.data.constants
 
 object ServerConstants {
     const val EMPTY_TEXT = ""
+    const val DEFAULT_LANG = "en"
 }
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/datasource/UserLocalDataSource.kt b/src/main/kotlin/es/wokis/data/datasource/UserLocalDataSource.kt
index 12e6e5f..6b44867 100644
--- a/src/main/kotlin/es/wokis/data/datasource/UserLocalDataSource.kt
+++ b/src/main/kotlin/es/wokis/data/datasource/UserLocalDataSource.kt
@@ -20,6 +20,7 @@ interface UserLocalDataSource {
     suspend fun getUserByUsernameOrEmail(username: String, email: String = EMPTY_TEXT): UserBO?
 
     suspend fun createUser(user: UserBO): Boolean
+    suspend fun updateUser(user: UserBO): Boolean
 }
 
 class UserLocalDataSourceImpl(private val userCollection: MongoCollection<UserDBO>) : UserLocalDataSource {
@@ -60,4 +61,9 @@ class UserLocalDataSourceImpl(private val userCollection: MongoCollection<UserDB
             false
         }
     }
+
+    override suspend fun updateUser(user: UserBO): Boolean {
+        val bsonId: Id<UserDBO> = ObjectId(user.id).toId()
+        return userCollection.updateOne(UserDBO::id eq bsonId, user.toDBO()).wasAcknowledged()
+    }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/dbo/user/UserDBO.kt b/src/main/kotlin/es/wokis/data/dbo/user/UserDBO.kt
index 8261d35..59dabec 100644
--- a/src/main/kotlin/es/wokis/data/dbo/user/UserDBO.kt
+++ b/src/main/kotlin/es/wokis/data/dbo/user/UserDBO.kt
@@ -1,5 +1,6 @@
 package es.wokis.data.dbo.user
 
+import es.wokis.data.constants.ServerConstants
 import org.bson.codecs.pojo.annotations.BsonId
 import org.litote.kmongo.Id
 
@@ -9,5 +10,7 @@ data class UserDBO(
     val username: String,
     val email: String,
     val password: String,
+    val lang: String,
+    val image: String = ServerConstants.EMPTY_TEXT,
     val devices: List<String> = emptyList()
 )
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/dto/user/UserDTO.kt b/src/main/kotlin/es/wokis/data/dto/user/UserDTO.kt
index 175344d..28bf509 100644
--- a/src/main/kotlin/es/wokis/data/dto/user/UserDTO.kt
+++ b/src/main/kotlin/es/wokis/data/dto/user/UserDTO.kt
@@ -7,5 +7,6 @@ data class UserDTO(
     val username: String,
     val email: String,
     val image: String = ServerConstants.EMPTY_TEXT,
+    val lang: String,
     val devices: List<String> = emptyList()
 )
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/dto/user/auth/Auth.kt b/src/main/kotlin/es/wokis/data/dto/user/auth/Auth.kt
index c3e7aa6..45bb9ae 100644
--- a/src/main/kotlin/es/wokis/data/dto/user/auth/Auth.kt
+++ b/src/main/kotlin/es/wokis/data/dto/user/auth/Auth.kt
@@ -1,12 +1,17 @@
 package es.wokis.data.dto.user.auth
 
+import es.wokis.data.constants.ServerConstants.DEFAULT_LANG
+
 data class LoginDTO(
     val username: String,
-    val password: String
+    val password: String,
+    val isGoogleAuth: Boolean = false
 )
 
 data class RegisterDTO(
     val username: String,
     val email: String,
-    val password: String
+    val password: String,
+    val lang: String = DEFAULT_LANG,
+    val isGoogleAuth: Boolean = false
 )
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/mapper/user/UserMapper.kt b/src/main/kotlin/es/wokis/data/mapper/user/UserMapper.kt
index c49d80e..ff24351 100644
--- a/src/main/kotlin/es/wokis/data/mapper/user/UserMapper.kt
+++ b/src/main/kotlin/es/wokis/data/mapper/user/UserMapper.kt
@@ -13,6 +13,7 @@ import org.mindrot.jbcrypt.BCrypt
 fun RegisterDTO.toBO() = UserBO(
     username = username,
     email = email,
+    lang = lang,
     password = BCrypt.hashpw(password, BCrypt.gensalt()),
 )
 
@@ -27,6 +28,7 @@ fun UserDTO.toBO() = UserBO(
     email = email,
     password = EMPTY_TEXT,
     image = image,
+    lang = lang,
     devices = devices
 )
 
@@ -34,7 +36,9 @@ fun UserBO.toDBO() = UserDBO(
     id = id?.let { ObjectId(it).toId() },
     username = username,
     email = email,
-    password = password.orEmpty(),
+    password = password,
+    lang = lang,
+    image = image,
     devices = devices
 )
 
@@ -43,6 +47,8 @@ fun UserDBO.toBO() = UserBO(
     username = username,
     email = email,
     password = password,
+    image = image,
+    lang = lang,
     devices = devices
 )
 
@@ -53,5 +59,6 @@ fun UserBO.toDTO() = UserDTO(
     username = username,
     email = email,
     image = image,
+    lang = lang,
     devices = devices
 )
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/data/repository/user/UserRepository.kt b/src/main/kotlin/es/wokis/data/repository/user/UserRepository.kt
index 721f59b..26eb4b7 100644
--- a/src/main/kotlin/es/wokis/data/repository/user/UserRepository.kt
+++ b/src/main/kotlin/es/wokis/data/repository/user/UserRepository.kt
@@ -1,22 +1,31 @@
 package es.wokis.data.repository.user
 
-import com.google.firebase.auth.hash.Bcrypt
+import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken
+import com.google.api.client.googleapis.auth.oauth2.GoogleIdTokenVerifier
+import com.google.api.client.http.javanet.NetHttpTransport
+import com.google.api.client.json.gson.GsonFactory
 import es.wokis.data.bo.user.UserBO
+import es.wokis.data.constants.ServerConstants.DEFAULT_LANG
+import es.wokis.data.constants.ServerConstants.EMPTY_TEXT
 import es.wokis.data.datasource.UserLocalDataSource
 import es.wokis.data.dto.user.auth.LoginDTO
 import es.wokis.data.dto.user.auth.RegisterDTO
 import es.wokis.data.mapper.user.toBO
+import es.wokis.plugins.config
 import es.wokis.plugins.makeToken
+import es.wokis.utils.HashGenerator
+import es.wokis.utils.generatePassword
 import org.mindrot.jbcrypt.BCrypt
-import kotlin.math.log
 
 interface UserRepository {
     suspend fun login(login: LoginDTO): String?
+    suspend fun loginWithGoogle(googleToken: String): String?
     suspend fun register(register: RegisterDTO): String?
     suspend fun getUsers(): List<UserBO>
     suspend fun getUserById(id: String?): UserBO?
     suspend fun getUserByUsername(name: String?): UserBO?
     suspend fun getUserByEmail(email: String?): UserBO?
+    suspend fun updateUser(user: UserBO): Boolean
 }
 
 class UserRepositoryImpl(private val userLocalDataSource: UserLocalDataSource) : UserRepository {
@@ -33,6 +42,57 @@ class UserRepositoryImpl(private val userLocalDataSource: UserLocalDataSource) :
         }
     }
 
+    override suspend fun loginWithGoogle(googleToken: String): String? {
+        val verifier: GoogleIdTokenVerifier =
+            GoogleIdTokenVerifier.Builder(
+                NetHttpTransport(),
+                GsonFactory()
+            )
+                .setAudience(listOf(config.getString("google.clientId")))
+                .setIssuer("https://accounts.google.com")
+                .build()
+
+        return verifier.verify(googleToken)?.let {
+            val payload: GoogleIdToken.Payload = it.payload
+
+            // Print user identifier
+            val userId: String = payload.subject
+            println("User ID: $userId")
+
+            // Get profile information from payload
+            val email: String = payload.email
+            val imageUrl: String = (payload["picture"] as? String).orEmpty()
+            val locale: String = payload["locale"] as? String ?: DEFAULT_LANG
+            val username = email.split("@").firstOrNull() ?: HashGenerator.generateHash()
+            val user = getUserByEmail(email)
+            val token = if (user == null) {
+                val token = register(
+                    RegisterDTO(
+                        username = username,
+                        email = email,
+                        password = EMPTY_TEXT,
+                        isGoogleAuth = true,
+                        lang = locale
+                    )
+                )
+                getUserByEmail(email)?.let { userNotNull ->
+                    updateUser(
+                        userNotNull.copy(
+                            image = imageUrl
+                        )
+                    )
+                }
+               token
+
+            } else {
+                login(
+                    LoginDTO(username = username, password = EMPTY_TEXT, isGoogleAuth = true)
+                )
+            }
+            token
+        }
+    }
+
     override suspend fun register(register: RegisterDTO): String? {
         val currentUser = userLocalDataSource.getUserByUsernameOrEmail(register.username, register.email)
         val user = register.toBO()
@@ -65,4 +125,5 @@ class UserRepositoryImpl(private val userLocalDataSource: UserLocalDataSource) :
         userLocalDataSource.getUserByEmail(it)
     }
 
+    override suspend fun updateUser(user: UserBO): Boolean = userLocalDataSource.updateUser(user)
 }
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/plugins/Security.kt b/src/main/kotlin/es/wokis/plugins/Security.kt
index a0b9eb9..d1b5221 100644
--- a/src/main/kotlin/es/wokis/plugins/Security.kt
+++ b/src/main/kotlin/es/wokis/plugins/Security.kt
@@ -3,12 +3,15 @@ package es.wokis.plugins
 import com.auth0.jwt.JWT
 import com.auth0.jwt.JWTVerifier
 import com.auth0.jwt.algorithms.Algorithm
+import com.google.firebase.auth.hash.Bcrypt
 import es.wokis.data.bo.user.UserBO
 import es.wokis.data.repository.user.UserRepository
+import es.wokis.utils.orGeneratePassword
 import io.ktor.server.application.*
 import io.ktor.server.auth.*
 import io.ktor.server.auth.jwt.*
 import org.koin.ktor.ext.inject
+import org.mindrot.jbcrypt.BCrypt
 import java.util.*
 
 private lateinit var jwtIssuer: String
@@ -59,6 +62,6 @@ fun makeToken(user: UserBO): String =
         .withIssuer(jwtIssuer)
         .withAudience(jwtAudience)
         .withClaim("username", user.username)
-        .withClaim("password", user.password)
+        .withClaim("password", user.password.takeIf { it.isNotBlank() }.orGeneratePassword() )
         .withClaim("timestamp", Date().time)
         .sign(algorithm)
diff --git a/src/main/kotlin/es/wokis/routing/AuthRouting.kt b/src/main/kotlin/es/wokis/routing/AuthRouting.kt
index c68c415..cc21e4e 100644
--- a/src/main/kotlin/es/wokis/routing/AuthRouting.kt
+++ b/src/main/kotlin/es/wokis/routing/AuthRouting.kt
@@ -35,4 +35,12 @@ fun Routing.setUpAuthRouting() {
             call.respond(HttpStatusCode.Conflict, "That user already exists")
         }
     }
+
+    post("/google-auth") {
+        val googleToken = call.receive<String>()
+        val token: String? = userRepository.loginWithGoogle(googleToken)
+        token?.let {
+            call.respond(HttpStatusCode.OK, it)
+        } ?: call.respond(HttpStatusCode.NotFound, "That user doesn't exists.")
+    }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/services/EmailService.kt b/src/main/kotlin/es/wokis/services/EmailService.kt
new file mode 100644
index 0000000..14e4383
--- /dev/null
+++ b/src/main/kotlin/es/wokis/services/EmailService.kt
@@ -0,0 +1,61 @@
+package es.wokis.services
+
+import es.wokis.data.bo.user.UserBO
+import es.wokis.data.bo.verification.VerificationBO
+import es.wokis.plugins.config
+import es.wokis.utils.HashGenerator
+import java.util.*
+import javax.mail.Message
+import javax.mail.MessagingException
+import javax.mail.Session
+import javax.mail.internet.InternetAddress
+import javax.mail.internet.MimeMessage
+
+class EmailService {
+    private val fromEmail = config.getString("mail.user")
+    private val fromPassword = config.getString("mail.pass")
+
+    private val about = "Invitacion"
+
+    fun sendEmail(user: UserBO): VerificationBO {
+        val emailHtml = this::class.java.getResource("/emails/${user.lang}/email-verify.html") ?: throw IllegalAccessException()
+
+        val properties: Properties = System.getProperties().apply {
+            put("mail.smtp.host", "email.wokis.es")
+            put("mail.smtp.user", fromEmail)
+            put("mail.smtp.clave", fromPassword)
+            put("mail.smtp.auth", "true")
+            put("mail.smtp.starttls.enable", "true")
+            put("mail.smtp.ssl.trust", "email.wokis.es");
+            put("mail.smtp.port", 587)
+        }
+        val hash = HashGenerator.generateHash(20)
+        val cuerpo = emailHtml.readText()
+
+        val session = Session.getDefaultInstance(properties)
+        val message = MimeMessage(session)
+
+        try {
+            with(message) {
+                setFrom(InternetAddress(fromEmail))
+                addRecipients(Message.RecipientType.TO, user.email)
+                subject = about
+                setContent(cuerpo, "text/html")
+            }
+
+            with(session.getTransport("smtp")) {
+                connect("email.wokis.es", fromEmail, fromPassword)
+                sendMessage(message, message.allRecipients)
+                close()
+            }
+
+        } catch (e: MessagingException) {
+            println(e.message)
+        }
+
+        return VerificationBO(
+            email = user.email,
+            verificationToken = hash
+        )
+    }
+}
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/services/NotificationService.kt b/src/main/kotlin/es/wokis/services/NotificationService.kt
new file mode 100644
index 0000000..1431cac
--- /dev/null
+++ b/src/main/kotlin/es/wokis/services/NotificationService.kt
@@ -0,0 +1,24 @@
+package es.wokis.services
+
+import com.google.firebase.messaging.FirebaseMessaging
+import com.google.firebase.messaging.MulticastMessage
+import es.wokis.data.bo.user.UserBO
+
+
+fun sendNotifications(users: List<UserBO>) {
+    val registrationTokens: List<String> = users.flatMap { it.devices }
+
+    val message = MulticastMessage.builder()
+        .putData("score", "850")
+        .putData("time", "2:45")
+        .addAllTokens(registrationTokens)
+        .build()
+    val response = FirebaseMessaging.getInstance().sendMulticast(message)
+    if (response.failureCount > 0) {
+        val responses = response.responses
+        val failedTokens: List<String> = responses.mapIndexedNotNull { index, sendResponse ->
+            if (!sendResponse.isSuccessful) registrationTokens[index] else null
+        }
+        println("List of tokens that caused failures: $failedTokens")
+    }
+}
diff --git a/src/main/kotlin/es/wokis/utils/BooleanUtils.kt b/src/main/kotlin/es/wokis/utils/BooleanUtils.kt
new file mode 100644
index 0000000..562b6ae
--- /dev/null
+++ b/src/main/kotlin/es/wokis/utils/BooleanUtils.kt
@@ -0,0 +1,5 @@
+package es.wokis.utils
+
+fun Boolean?.isTrue() = this == true
+
+fun Boolean?.isFalse() = this == false
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/utils/CredentialsUtils.kt b/src/main/kotlin/es/wokis/utils/CredentialsUtils.kt
new file mode 100644
index 0000000..d78dd8f
--- /dev/null
+++ b/src/main/kotlin/es/wokis/utils/CredentialsUtils.kt
@@ -0,0 +1,12 @@
+package es.wokis.utils
+
+import es.wokis.data.bo.user.UserBO
+import io.ktor.server.application.*
+import io.ktor.server.auth.*
+import org.mindrot.jbcrypt.BCrypt
+
+val ApplicationCall.user: UserBO? get() = authentication.principal()
+
+fun String?.orGeneratePassword(): String = this ?: generatePassword()
+
+fun generatePassword() = BCrypt.hashpw(HashGenerator.generateHash(20), BCrypt.gensalt())
\ No newline at end of file
diff --git a/src/main/kotlin/es/wokis/utils/HashGenerator.kt b/src/main/kotlin/es/wokis/utils/HashGenerator.kt
new file mode 100644
index 0000000..69a09bd
--- /dev/null
+++ b/src/main/kotlin/es/wokis/utils/HashGenerator.kt
@@ -0,0 +1,23 @@
+
+package es.wokis.utils
+
+import es.wokis.data.constants.ServerConstants
+import java.util.*
+import kotlin.streams.asSequence
+
+object HashGenerator {
+        /**
+         * Genera un hash aleatorio con la longitud indicada.
+         *
+         * @param length la longitud del hash. Es opcional, tiene una de serie de 12 caracteres.
+         * @return el hash generado como [String]
+         *
+         */
+        fun generateHash(length: Long = 12L): String {
+            val hashSource = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_"
+            return Random().ints(length, 0, hashSource.length-1)
+                .asSequence()
+                .map(hashSource::get)
+                .joinToString(ServerConstants.EMPTY_TEXT)
+        }
+}
\ No newline at end of file
diff --git a/src/main/resources/app.conf b/src/main/resources/app.conf
index 7805653..e24c1a7 100644
--- a/src/main/resources/app.conf
+++ b/src/main/resources/app.conf
@@ -21,4 +21,9 @@ mail {
     pass = "abc123."
 }
 
-firebaseSdkDir = "config/firebaseSdk.json"
\ No newline at end of file
+firebaseSdkDir = "config/firebaseSdk.json"
+
+google {
+    clientId = "google_client_id"
+    clientSecret = "google_client_secret"
+}
\ No newline at end of file