diff --git a/src/main.cr b/src/main.cr
index 572fac0..08e8203 100644
--- a/src/main.cr
+++ b/src/main.cr
@@ -82,14 +82,24 @@ class AuthD::Service
 			user.contact.email = request.email
 			user.contact.phone = request.phone unless request.phone.nil?
 
-			pp! user
-
 			request.profile.try do |profile|
 				user.profile = profile
 			end
 
 			@users << user
 
+			# Once the user is created and stored, we try to contact him
+			# TODO: send a mail
+			unless Process.run("activation-mailer", [
+				"-l", user.login,
+				"-e", user.contact.email.not_nil!,
+				"-t", "Activation email",
+				"-f", "karchnu@localhost",
+				"-a", user.contact.activation_key.not_nil!
+				]).success?
+				return Response::Error.new "cannot contact the user"
+			end
+
 			Response::UserAdded.new user.to_public
 		when Request::ValidateUser
 			if request.shared_key != @jwt_key
@@ -102,6 +112,10 @@ class AuthD::Service
 				return Response::Error.new "user not found"
 			end
 
+			if user.contact.activation_key.nil?
+				return Response::Error.new "user already validated"
+			end
+
 			# remove the user contact activation key: the email is validated
 			if user.contact.activation_key == request.activation_key
 				user.contact.activation_key = nil