Objective We developed a smartphone application for patients with rheumatoid arthritis (RA) that allows them to self‐monitor their disease activity in between clinic visits by answering a weekly Routine Assessment of Patient Index Data 3. This study was undertaken to assess the safety (noninferiority in the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate DAS28‐ESR) and efficacy (reduction in number of visits) of patient‐initiated care assisted using a smartphone app, compared to usual care. Methods A 12‐month, randomized, noninferiority clinical trial was conducted in RA patients with low disease activity and without treatment changes in the past 6 months. Patients were randomized 1:1 to either app‐supported patient‐initiated care with a scheduled follow‐up consultation after a year (app intervention group) or usual care. The coprimary outcome measures were noninferiority in terms of change in DAS28‐ESR score after 12 months and the ratio of the mean number of consultations with rheumatologists between the groups. The noninferiority limit was 0.5 difference in DAS28‐ESR between the groups. Results Of the 103 randomized patients, 102 completed the study. After a year, noninferiority in terms of the DAS28‐ESR score was established, as the 95% confidence interval (95% CI) of the mean ΔDAS28‐ESR between the groups was within the noninferiority limit: −0.04 in favor of the app intervention group (95% CI −0.39, 0.30). The number of rheumatologist consultations was significantly lower in the app intervention group compared to the usual care group (mean ± SD 1.7 ± 1.8 versus 2.8 ± 1.4; visit ratio 0.62 95% CI 0.47, 0.81). Conclusion Patient‐initiated care supported by smartphone self‐monitoring was noninferior to usual care in terms of the ΔDAS28‐ESR and led to a 38% reduction in rheumatologist consultations in RA patients with stable low disease activity.