Inclusion Criteria:  18-65 years old Being able to read and understand Spanish Being able to use a smartphone Having an Android smartphone with internet connection Suffering from mild to moderate depressive symptoms (from 14 to 28 on the Beck Depression Inventory-II [BDI-II]  Exclusion Criteria:  Suffering a severe mental disorder: bipolar disorder, alcohol and/ or substance dependence disorder, psychotic disorder, or dementia Having a high suicide risk (ideation or plan assessed by the MINI and item 9 of the BDI-II) Receiving another psychological treatment while the study is still ongoing.