Inclusion Criteria:  Adults with confirmed congestive HF registered at the outpatient heart failure clinic at the Landspitali University Hospital Participants should be on one of these medications for heart failure treatment: angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blocker (ARB) inhibitors, or Angiotensin Receptor-Neprilysin Inhibitor Participants with all stages of HF will be included (NYHA classes I-IV) Started their medical HF treatment at least 1 month prior to study enrollment Participants should be willing and able to comply with study procedures and attend the scheduled visits Capacity to consent to informed consent  Exclusion Criteria:  HF due to reversible causes (e.g., myocarditis) or severe aortic valve stenosis Not owning a smartphone compatible with the Sidekick Health digital solution Not knowing how to operate a smartphone Moderate to severe dementia Unable to understand written and verbal instructions in Icelandic. estimated Glomerular Filtration Rate (eGFR) <15 ml/min Planned dialysis in the next 6 months Planned cardiac transplant surgery Active drug/alcohol abuse Other serious illness (e.g., cancer, endocarditis)