Abstract Background The expansion of digital devices and widespread access to the Internet has opened up opportunities to provide patients with more personal information. It can be hypothesized that eHealth in addition to standard care could enhance clinical outcomes such as increased weight loss, co-morbidity reduction, and commitment to the program. The beneficial value of incorporating eHealth applications as standard postoperative care is yet to be established. In this trial, the value of different levels of eHealth are assessed. Methods/design Two hundred adult patients with a body mass index (BMI) ≥ 40 kg/m2, or ≥ 35 kg/m2 with obesity-related co-morbidity, undergoing sleeve gastrectomy or gastric bypass will be enrolled in this randomized controlled trial. Patients will be randomly assigned to one of the groups: receiving standard care (control group, n = 100); have access to an online eHealth platform in addition to the previous group (online group, n = 50); or receive wireless monitoring devices in addition to previous groups (device group, n = 50). The total follow-up period is two years postoperatively. Primary outcome is weight loss in terms of BMI. Secondary outcomes include: quality of life; return-to-work time; co-morbidity reduction; additional contacts; and ease of use of devices. Discussion In this trial, the value of different levels of eHealth will be assessed. This addresses an important aspect of a changing healthcare environment. Trial registration Trialregister.nl, NTR6827. Retrospectively registered on 19 November 2017. http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=6827.