diff --git a/CHANGELOG b/CHANGELOG
index d625158472..3119c030e2 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,4 @@
+* Add UUID on line for synchronisation
 * Remove support for Python 2.7
 
 Version 4.8.0 - 2018-04-23
diff --git a/doc/user_application.rst b/doc/user_application.rst
index d70f3ea62b..9a3dc9f938 100644
--- a/doc/user_application.rst
+++ b/doc/user_application.rst
@@ -15,11 +15,13 @@ The timesheet module defines some routes for user applications:
     - `GET` `/<database_name>/timesheet/employee/<int:employee>/lines/<date>`:
       return the list of timesheet lines for the employee at the date
       (`%Y-%m-%d'). The lines are dictionary with keys: `id`, `work`,
-      `work.name`, `duration` and `description`. The duration is in seconds.
+      `work.name`, `duration`, `description` and `uuid`. The duration is in
+      seconds.
 
     - `POST` `/<database_name>/timesheet/line`:
       Create a line using the data as dictionary of value. The date must be in
-      the format `%Y-%m-%d` and the `duration` in seconds.
+      the format `%Y-%m-%d` and the `duration` in seconds. If a `uuid` value is
+      provided, it will update the record if found instead of create a new one.
 
     - `PUT` `/<database_name>/timesheet/line/<int:line>`:
       Update the line using the data like for the `POST`.
diff --git a/line.py b/line.py
index a45106e142..0cf5744740 100644
--- a/line.py
+++ b/line.py
@@ -7,7 +7,7 @@ from sql import Literal
 from sql.aggregate import Max, Sum
 from sql.functions import Extract, CharLength
 
-from trytond.model import ModelView, ModelSQL, fields
+from trytond.model import ModelView, ModelSQL, fields, Unique
 from trytond.wizard import Wizard, StateView, StateAction, Button
 from trytond.pyson import Eval, PYSONEncoder, Date
 from trytond.transaction import Transaction
@@ -56,10 +56,16 @@ class Line(ModelSQL, ModelView):
         help="The work on which the time is spent.")
     description = fields.Char('Description',
         help="Additional description of the work done.")
+    uuid = fields.Char("UUID", readonly=True)
 
     @classmethod
     def __setup__(cls):
         super(Line, cls).__setup__()
+        t = cls.__table__()
+        cls._sql_constraints = [
+            ('uuid_unique', Unique(t, t.uuid),
+                "The UUID of timesheet line must be unique."),
+            ]
         cls._order.insert(0, ('date', 'DESC'))
         cls._error_messages.update({
                 'duration_positive': (
@@ -136,6 +142,16 @@ class Line(ModelSQL, ModelView):
     def hours(self):
         return self.duration.total_seconds() / 60 / 60
 
+    def to_json(self):
+        return {
+            'id': self.id,
+            'work': self.work.id,
+            'work.name': self.work.rec_name,
+            'duration': self.duration.total_seconds(),
+            'description': self.description,
+            'uuid': self.uuid,
+            }
+
 
 class EnterLinesStart(ModelView):
     'Enter Lines'
diff --git a/routes.py b/routes.py
index b4ec45bc18..7276eaf187 100644
--- a/routes.py
+++ b/routes.py
@@ -69,13 +69,7 @@ def timesheet_lines(request, pool, employee, date):
                 ('employee', '=', employee.id),
                 ('date', '=', date),
                 ])
-    return [{
-            'id': l.id,
-            'work': l.work.id,
-            'work.name': l.work.rec_name,
-            'duration': l.duration.total_seconds(),
-            'description': l.description,
-            } for l in lines]
+    return [l.to_json() for l in lines]
 
 
 @app.route('/<database_name>/timesheet/line/<int:line>',
@@ -90,6 +84,14 @@ def timesheet(request, pool, line=None):
     Employee = pool.get('company.employee')
     if request.method in {'POST', 'PUT'}:
         data = request.parsed_data.copy()
+
+        if not line and data.get('uuid'):
+            lines = Line.search([
+                    ('uuid', '=', data['uuid']),
+                    ])
+            if lines:
+                line, = lines
+
         if 'employee' in data:
             employee = Employee(data['employee'])
             data['company'] = employee.company.id
@@ -115,13 +117,7 @@ def timesheet(request, pool, line=None):
                     return Response(None, 204)
                 line, = lines
                 Line.write(lines, data)
-        return {
-            'id': line.id,
-            'work': line.work.id,
-            'work.name': line.work.rec_name,
-            'duration': line.duration.total_seconds(),
-            'description': line.description,
-            }
+        return line.to_json()
     else:
         with Transaction().set_user(0):
             lines = Line.search([('id', '=', line)])