Abstract Objectives Gout flares are painful and disabling. We developed a smartphone application (app) for patients to tele-monitor gout flares surveyed by clinicians. The aim of this study was to assess patient acceptability and technical and clinical feasibility. Methods Adult patients with either established gout or high suspicion thereof were recruited if they possessed a smartphone and reported a recent arthritis attack. A smartphone application was used to identify gout flares by asking during 90 consecutive days: (1) what is your pain score (0–10); (2) are your joints warm; (3) are your joints swollen; and (4) are you currently experiencing a gout flare? The clinician was alerted via email if a flare occurred. Patient acceptability was assessed using the technology acceptance model. Technical feasibility consisted of reported technical issues and clinical feasibility of actions taken by the clinician regarding gout flare alerts. Results Twenty-nine included patients completed the study. The mean age of participants was 57 years, and all but one were male. The adherence rate was 96% (110 of 2910 queries were missed). Patients had a positive attitude toward app use, found the app very easy to use (mean usability score 81 out of 100) and were neutral to positive on its usefulness. There were four minor technical issues. A total of 100 gout flare alerts were generated that led to 18 proactive contacts with patients. Conclusion A smartphone app to monitor gout flares was developed and tested, showing high adherence, good acceptability and clinical feasibility for established gout patients. Trial registration Netherlands Trial Register, https://www.trialregister.nl, NL6435.